[am4show have=’p2;’]

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[/am4show]

Question 1

[am4show have=’p2;’]Which statements are true regarding ICMP packets? (Choose two)

A. They acknowledge receipt of TCP segments.
B. They guarantee datagram delivery
C. TRACERT uses ICMP packets.
D. They are encapsulated within IP datagrams.
E. They are encapsulated within UDP datagrams

Answer: C D[/am4show]

Explanation

Tracert (or traceroute) is used to trace the path between the sender and the destination host. Traceroute works by sending packets with gradually increasing Time-to-Live (TTL) value, starting with TTL value = 1. The first router receives the packet, decrements the TTL value and drops the packet because it then has TTL value zero. The router sends an ICMP Time Exceeded message back to the source. The next set of packets are given a TTL value of 2, so the first router forwards the packets, but the second router drops them and replies with ICMP Time Exceeded. Proceeding in this way, traceroute uses the returned ICMP Time Exceeded messages to build a list of routers that packets traverse, until the destination is reached and returns an ICMP Echo Reply message -> C is correct.

ICMP is encapsulated in an IP packet. In particular, the ICMP message is encapsulated in the IP payload part of an IP datagram -> D is correct.

Note: The TRACERT command on Windows Operating System uses ICMP while MAC OS X and Linux TRACEROUTE use UDP.

Question 2

[am4show have=’p2;’]Refer to the exhibit. An administrator cannot connect from R1 to R2. To troubleshoot this problem, the administrator has entered the command shown in the exhibit. Based on the output shown, what could be the problem?

A. The serial interface is configured for half duplex.
B. The serial interface does not have a cable attached.
C. The serial interface has the wrong type of cable attached.
D. The serial interface is configured for the wrong frame size.
E. The serial interface has a full buffer.

Answer: C[/am4show]

Explanation

The output above is unclear. Normally when we use this command we can see the type of serial connection on this interface, for example “V.35 DCE cable. Below is an example of the same command as above:

Or

but in this case we only get “V.35 cable”. So in fact we are not sure about the answer C. But the output above also does not have any information to confirm other answers are correct or not.

Just for your information, the V.35 male and V.35 female cable are shown below:

Question 3

[am4show have=’p2;’]How many simultaneous Telnet sessions does a Cisco router support by default?

A. 1
B. 2
C. 3
D. 4
E. 5
F. 6

Answer: E[/am4show]

Question 4

[am4show have=’p2;’]Which of the following is a characteristic of full-duplex communication?

A. It is a CSMA/CD network.
B. It is a CSMA/CA network.
C. It is point-to-point only.
D. Hub communication is done via full duplex.

Answer: C[/am4show]

Question 5

[am4show have=’p2;’]Which set of conditions comprises a successful ping attempt between two connected routers configured with IP addresses on the same subnet?

A. The destination host receives an echo reply from the source host within one second and the source host receives an echo request from the destination host.
B. The destination host receives an echo request from the source host within one second.
C. The destination host receives an echo reply from the source host within one second and the source host receives an echo reply from the destination host within two seconds.
D. The destination host receives an echo request from the source host and the source host receives an echo request from the destination host within one second.
E. The destination host receives an echo request from the source host and the source host receives an echo reply from the destination host within two seconds.

Answer: E[/am4show]

Explanation

The ping command first sends an echo request packet to an address, then waits for a reply. The ping is successful only if:
+ The echo request gets to the destination, and
+ The destination is able to get an echo reply back to the source within a predetermined time called a timeout. The default value of this timeout is two seconds on Cisco routers.

(Reference: http://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/ios-software-releases-121-mainline/12778-ping-traceroute.html)

[am4show have=’p2;’]

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Question 1

[am4show have=’p2;’]Which device allows users to connect to the network using a single or double radio?

A. access point
B. switch
C. wireless controller
D. firewall

Answer: A[/am4show]

Explanation

Many Cisco access points offer single or double (dual) radio (2.4 and 5.0 GHz).

Note: The wireless controller automates wireless configuration and management functions. It does not connect directly to users.

[am4show have=’p2;’]

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Question 1

[am4show have=’p2;’]Various protocols are listed on the left On the right are applications for the use of those protocols. Drag the protocol on the left to an associated function for that protocol on the right (Not all options are used)

Answer:

[/am4show]+ ARP: A PC sends packets to the default gateway IP address the first time since the PC turned on.
+ ICMP: The network administrator is checking basic IP connectivity from a workstation to a server.
+ DNS: The TCP/IP protocol stack must find an IP address for packets destined for a URL.
+ DHCP: A network device will automatically assign IP addresses to workstations.

Question 2

[am4show have=’p2;’]Move the protocol or service on the left to a situation on the right where it would be used. (Not all options are used)

Answer:

[/am4show]+ NAT: A PC with address 10.1.5.10 must access devices on the Internet.
+ DHCP: Only routers and servers require static IP addresses. Easy IP administration is required.
+ DNS: A PC only knows a server as MediaServer. IP needs to send data to that server.
+ OSPF: A protocol is needed to replace current static routes with automatic route updates.

Question 3

[am4show have=’p2;’]Drag the definition on the left to the correct term on the right. Not all definitions on the left will be used.

Answer:

[/am4show]+ SNMP: a protocol used to monitor and manage network devices
+ FTP: a reliable, connection-oriented service that uses TCP to transfer files between systems
+ TFTP: a connectionless service that uses UDP to transfer files between systems
+ DNS: a protocol that converts human-readable names into machine-readable addresses
+ DHCP: used to assign IP addresses automatically and set parameters such as subnet mask and default gateway

Question 4

[am4show have=’p2;’]Drag the appropriate command on the left to the configuration task it accomplishes (not all options are used)

Answer:

[/am4show]

Question 5

[am4show have=’p2;’]On the left are various network protocols. On the right are the layers of the TCP/IP model. Assuming a reliable connection is required, move the protocols on the left to the TCP/IP layers on the right to show the proper encapsulation for an email message sent by a host on a LAN. (Not all options are used)

Answer:

[/am4show]+ application layer: SMTP
+ transport layer: TCP
+ internet layer: IP
+ network access layer: Ethernet

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[am4show have=’p2;’]

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Question

[am4show have=’p2;’]RouterA and SwitchA have been configured to operate in a private network which will connect to the Internet. you have been asked to review the configuration prior to cabling and implementation.
This task requires the use of various commands to access and check the running configuration of the two devices. No configuration changes are necessary (and the configuration command has been disabled for these two devices).[/am4show]

Read more…

You can try the DHCP Simulator here:
+ DHCP Simulator

[am4show have=’p2;’]

Premium Member: You can practice this sim with our simulator here.[/am4show]

Refer to the topology below and answer the following questions.

Read more…

You can try the ICND2 – GRE Multilink Simulator here:

+ GRE Multilink Simulator

and read the explanation of this sim at https://www.9tut.net/icnd2/icnd2-labsim/gre-multilink-sim.

The new ICND2 200-105 exam has come to replace the old ICND2 200-101 exam. We create the “Share your ICND2 v3.0 Experience” for everyone to share their experience after taking this exam.

Note for ICND2: There are no VRRP, GLBP, NetFlow and NAT questions (and they are not technologies learned in this exam).

Please share with us your experience after taking the ICND2 200-105 exam, your materials, the way you learned, your recommendations… But please DO NOT share any information about the detail of the exam or your personal information, your score, exam date and location, your email…

The ICND1 100-105 exam has come to replace the old ICND1 100-101 exam. We create the “Share your ICND1 v3.0 Experience” for everyone to share their experience after taking this exam.

Please share with us your experience after taking the ICND1 100-105 exam, your materials, the way you learned, your recommendations… But please DO NOT share any information about the detail of the exam or your personal information, your score, exam date and location, your email…

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Note: If you are not sure about HSRP and GLBP, please read our HSRP tutorial and GLBP tutorial.

Question 1

[am4show have=’p2;’]Which one of these is a valid HSRP Virtual Mac Address?

A. 0000.0C07.AC01
B. 0000.5E00.0110
C. 0007.B400.1203
D. 0000.C007.0201

Answer: A[/am4show]

Explanation

With HSRP, two or more devices support a virtual router with a fictitious MAC address and unique IP address. There are two version of HSRP.

+ With HSRP version 1, the virtual router’s MAC address is 0000.0c07.ACxx , in which xx is the HSRP group.
+ With HSRP version 2, the virtual MAC address if 0000.0C9F.Fxxx, in which xxx is the HSRP group.

Note: Another case is HSRP for IPv6, in which the MAC address range from 0005.73A0.0000 through 0005.73A0.0FFF.

-> A is correct.

(Good resource for HSRP: http://www.cisco.com/en/US/docs/switches/datacenter/sw/5_x/nx-os/unicast/configuration/guide/l3_hsrp.html)

Question 2

[am4show have=’p2;’]Which three statements about HSRP operation are true? (Choose three)

A. The virtual IP address and virtual MAC address are active on the HSRP Master router.
B. The HSRP default timers are a 3 second hello interval and a 10 second dead interval.
C. HSRP supports only clear-text authentication.
D. The HSRP virtual IP address must be on a different subnet than the routers’ interfaces on the same LAN.
E. The HSRP virtual IP address must be the same as one of the router’s interface addresses on the LAN.
F. HSRP supports up to 255 groups per interface, enabling an administrative form of load balancing.

Answer: A B F[/am4show]

Explanation

The virtual MAC address of HSRP version 1 is 0000.0C07.ACxx, where xx is the HSRP group number in hexadecimal based on the respective interface. For example, HSRP group 10 uses the HSRP virtual MAC address of 0000.0C07.AC0A. HSRP version 2 uses a virtual MAC address of 0000.0C9F.FXXX (XXX: HSRP group in hexadecimal)

For more information about HSRP operation, please read our HSRP tutorial.

Question 3

[am4show have=’p2;’]Which statement describes VRRP object tracking?

A. It monitors traffic flow and link utilization.
B. It ensures the best VRRP router is the virtual router master for the group.
C. It causes traffic to dynamically move to higher bandwidth links
D. It thwarts man-in-the-middle attacks.

Answer: B[/am4show]

Explanation

Object tracking is the process of tracking the state of a configured object and uses that state to determine the priority of the VRRP router in a VRRP group -> B is correct.

(Reference: http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/unicast/configuration/guide/l3_cli_nxos/l3_vrrp.html#wp1074871)

Note: Unlike HSRP which can track interface status directly, VRRP can only track interface status through a tracked object.

Question 4

[am4show have=’p2;’]In GLBP, which router will respond to client ARP requests?

A. The active virtual gateway will reply with one of four possible virtual MAC addresses.
B. All GLBP member routers will reply in round-robin fashion.
C. The active virtual gateway will reply with its own hardware MAC address.
D. The GLBP member routers will reply with one of four possible burned in hardware addresses.

Answer: A[/am4show]

Explanation

One disadvantage of HSRP and VRRP is that only one router is in use, other routers must wait for the primary to fail because they can be used. However, Gateway Load Balancing Protocol (GLBP) can use of up to four routers simultaneously. In GLBP, there is still only one virtual IP address but each router has a different virtual MAC address. First a GLBP group must elect an Active Virtual Gateway (AVG). The AVG is responsible for replying ARP requests from hosts/clients. It replies with different virtual MAC addresses that correspond to different routers (known as Active Virtual Forwarders – AVFs) so that clients can send traffic to different routers in that GLBP group (load sharing).

Question 5

[am4show have=’p2;’]In a GLBP network, who is responsible for the arp request?

A. AVF
B. AVG
C. Active Router
D. Standby Router

Answer: B[/am4show]

Question 6

[am4show have=’p2;’]What are three benefits of GLBP? (Choose three)

A. GLBP supports up to eight virtual forwarders per GLBP group.
B. GLBP supports clear text and MD5 password authentication between GLBP group members.
C. GLBP is an open source standardized protocol that can be used with multiple vendors.
D. GLBP supports up to 1024 virtual routers.
E. GLBP can load share traffic across a maximum of four routers.
F. GLBP elects two AVGs and two standby AVGs for redundancy.

Answer: B D E[/am4show]

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

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Question 1

[am4show have=’p2;’]What are the benefit of using Netflow? (Choose three)

A. Network, Application & User Monitoring

B. Network Planning

C. Security Analysis

D. Accounting/Billing

Answer: A C D[/am4show]

Explanation

NetFlow traditionally enables several key customer applications including:

+ Network Monitoring – NetFlow data enables extensive near real time network monitoring capabilities. Flow-based analysis techniques may be utilized to visualize traffic patterns associated with individual routers and switches as well as on a network-wide basis (providing aggregate traffic or application based views) to provide proactive problem detection, efficient troubleshooting, and rapid problem resolution.

+ Application Monitoring and Profiling – NetFlow data enables network managers to gain a detailed, time-based, view of application usage over the network. This information is used to plan, understand new services, and allocate network and application resources (e.g. Web server sizing and VoIP deployment) to responsively meet customer demands.

+ User Monitoring and Profiling – NetFlow data enables network engineers to gain detailed understanding of customer/user utilization of network and application resources. This information may then be utilized to efficiently plan and allocate access, backbone and application resources as well as to detect and resolve potential security and policy violations.

+ Network Planning – NetFlow can be used to capture data over a long period of time producing the opportunity to track and anticipate network growth and plan upgrades to increase the number of routing devices, ports, or higher- bandwidth interfaces. NetFlow services data optimizes network planning including peering, backbone upgrade planning, and routing policy planning. NetFlow helps to minimize the total cost of network operations while maximizing network performance, capacity, and reliability. NetFlow detects unwanted WAN traffic, validates bandwidth and Quality of Service (QOS) and allows the analysis of new network applications. NetFlow will give you valuable information to reduce the cost of operating your network.

+ Security Analysis – NetFlow identifies and classifies DDOS attacks, viruses and worms in real-time. Changes in network behavior indicate anomalies that are clearly demonstrated in NetFlow data. The data is also a valuable forensic tool to understand and replay the history of security incidents.

+ Accounting/Billing – NetFlow data provides fine-grained metering (e.g. flow data includes details such as IP addresses, packet and byte counts, timestamps, type-of-service and application ports, etc.) for highly flexible and detailed resource utilization accounting. Service providers may utilize the information for billing based on time-of-day, bandwidth usage, application usage, quality of service, etc. Enterprise customers may utilize the information for departmental charge-back or cost allocation for resource utilization.

(Reference: http://www.cisco.com/en/US/products/sw/netmgtsw/ps1964/products_implementation_design_guide09186a00800d6a11.html#wp1030045)

Question 2

[am4show have=’p2;’]What are the three things that the NetFlow uses to consider the traffic to be in a same flow?

A. IP address

B. Interface name

C. Port numbers

D. L3 protocol type

E. MAC address

Answer: A C D[/am4show]

Explanation

What is an IP Flow?

Each packet that is forwarded within a router or switch is examined for a set of IP packet attributes. These attributes are the IP packet identity or fingerprint of the packet and determine if the packet is unique or similar to other packets.

Traditionally, an IP Flow is based on a set of 5 and up to 7 IP packet attributes.

IP Packet attributes used by NetFlow:

+ IP source address

+ IP destination address

+ Source port

+ Destination port

+ Layer 3 protocol type

+ Class of Service

+ Router or switch interface

(Reference: http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-netflow/prod_white_paper0900aecd80406232.html)

Question 3

[am4show have=’p2;’]What NetFlow component can be applied to an interface to track IPv4 traffic?

A. flow monitor

B. flow record

C. flow sampler

D. flow exporter

Answer: A[/am4show]

Explanation

Flow monitors are the Flexible NetFlow component that is applied to interfaces to perform network traffic monitoring. Flow monitors consist of a record and a cache. You add the record to the flow monitor after you create the flow monitor. The flow monitor cache is automatically created at the time the flow monitor is applied to the first interface. Flow data is collected from the network traffic during the monitoring process based on the key and nonkey fields in the record, which is configured for the flow monitor and stored in the flow monitor cache.

For example, the following example creates a flow monitor named FLOW-MONITOR-1 and enters Flexible NetFlow flow monitor configuration mode:

Router(config)# flow monitor FLOW-MONITOR-1

Router(config-flow-monitor)#

(Reference: http://www.cisco.com/c/en/us/td/docs/ios/fnetflow/command/reference/fnf_book/fnf_01.html#wp1314030)

Question 4

[am4show have=’p2;’]What command visualizes the general NetFlow data on the command line?

A. show ip flow export

B. show ip flow top-talkers

C. show ip cache flow

D. show mls sampling

E. show mls netflow ip

Answer: C[/am4show]

Explanation

The “show ip cache flow” command displays a summary of the NetFlow accounting statistics.

Question 5

[am4show have=’p2;’]What are three reasons to collect NetFlow data on a company network? (Choose three)

A. To identify applications causing congestion.

B. To authorize user network access.

C. To report and alert link up / down instances.

D. To diagnose slow network performance, bandwidth hogs, and bandwidth utilization.

E. To detect suboptimal routing in the network.

F. To confirm the appropriate amount of bandwidth that has been allocated to each Class of Service.

Answer: A D F[/am4show]

Explanation

NetFlow facilitates solutions to many common problems encountered by IT professionals.

+ Analyze new applications and their network impact

Identify new application network loads such as VoIP or remote site additions.

+ Reduction in peak WAN traffic

Use NetFlow statistics to measure WAN traffic improvement from application-policy changes; understand who is utilizing the network and the network top talkers.

+ Troubleshooting and understanding network pain points

Diagnose slow network performance, bandwidth hogs and bandwidth utilization quickly with command line interface or reporting tools. -> D is correct.

+ Detection of unauthorized WAN traffic

Avoid costly upgrades by identifying the applications causing congestion. -> A is correct.

+ Security and anomaly detection

NetFlow can be used for anomaly detection and worm diagnosis along with applications such as Cisco CS-Mars.

+ Validation of QoS parameters

Confirm that appropriate bandwidth has been allocated to each Class of Service (CoS) and that no CoS is over- or under-subscribed.-> F is correct.

(Reference: http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-netflow/prod_white_paper0900aecd80406232.html)

Question 6

[am4show have=’p2;’]What are three factors a network administrator must consider before implementing Netflow in the network? (Choose three)

A. CPU utilization

B. where Netflow data will be sent

C. number of devices exporting Netflow data

D. port availability

E. SNMP version

F. WAN encapsulation

Answer: A B C[/am4show]

Question 7

[am4show have=’p2;’]What Cisco IOS feature can be enabled to pinpoint an application that is causing slow network performance?

A. SNMP

B. Netflow

C. WCCP

D. IP SLA

Answer: B[/am4show]

[am4show have=’p2;’]

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[/am4show]

Question 1

[am4show have=’p2;’]Which two statements about using the CHAP authentication mechanism in a PPP link are true? (Choose two)

A. CHAP uses a two-way handshake.
B. CHAP uses a three-way handshake.
C. CHAP authentication periodically occurs after link establishment.
D. CHAP authentication passwords are sent in plaintext.
E. CHAP authentication is performed only upon link establishment.
F. CHAP has no protection from playback attacks.

Answer: B C[/am4show]

Explanation

Point-to-Point Protocol (PPP) can use either Password Authentication Protocol (PAP) or Challenge Handshake Authentication Protocol (CHAP) for authentication. CHAP is used upon initial link establishment and periodically to make sure that the router is still communicating with the same host. CHAP passwords arc exchanged as message digest algorithm 5 (MD5) hash values.

The three-way handshake steps are as follows:

Challenge: The authenticator generates a frame called a Challenge and sends it to the initiator. This frame contains a simple text message (sometimes called the challenge text). The message has no inherent special meaning so it doesn’t matter if anyone intercepts it. The important thing is that after receipt of the Challenge both devices have the same challenge message.

Response: The initiator uses its password (or some other shared “secret” that the authenticators also knows) to encrypt the challenge text. It then sends the encrypted challenge text as a Response back to the authenticator.

Success or Failure: The authenticator performs the same encryption on the challenge text that the initiator did. If the authenticator gets the same result that the initiator sent it in the Response, the authenticator knows that the initiator had the right password when it did its encryption, so the authenticator sends back a Success message. Otherwise, it sends a Failure message.

(Reference: CCNA Quick Reference Sheets)

Question 2

[am4show have=’p2;’]Refer to the exhibit. Hosts in network 192.168.2.0 are unable to reach hosts in network 192.168.3.0. Based on the output from RouterA, what are two possible reasons for the failure? (Choose two)

A. The cable that is connected to S0/0 on RouterA is faulty.
B. Interface S0/0 on RouterB is administratively down.
C. Interface S0/0 on RouterA is configured with an incorrect subnet mask.
D. The IP address that is configured on S0/0 of RouterB is not in the correct subnet.
E. Interface S0/0 on RouterA is not receiving a clock signal from the CSU/DSU.
F. The encapsulation that is configured on S0/0 of RouterB does not match the encapsulation that is configured on S0/0 of RouterA.

Answer: E F[/am4show]

Explanation

From the output we see the Serial0/0 of RouterA is in “status up/protocol down” state which indicates a Layer 2 problem so the problem can be:

+ Keepalives mismatch
+ Encapsulation mismatch
+ Clocking problem

Question 3

[am4show have=’p2;’]Which command is used to enable CHAP authentication with PAP as the fallback method on a serial interface?

A. (config-if)# authentication ppp chap fallback ppp
B. (config-if)# authentication ppp chap pap
C. (config-if)# ppp authentication chap pap
D. (config-if)# ppp authentication chap fallback ppp

Answer: C[/am4show]

Explanation

The command “ppp authentication chap pap” command indicates the CHAP authentication is used first. If it fails or is rejected by other side then uses PAP instead. If you want to use PAP first (then CHAP) you can use the “ppp authentication pap chap” command.

Question 4

[am4show have=’p2;’]Which Layer 2 protocol encapsulation type supports synchronous and asynchronous circuits and has built-in security mechanisms?

A. HDLC
B. PPP
C. X.25
D. Frame Relay

Answer: B[/am4show]

Explanation

PPP supports both synchronous (like analog phone lines) and asynchronous circuits (such as ISDN or digital links). With synchronous circuits we need to use clock rate.

Note: Serial links can be synchronous or asynchronous. Asynchronous connections used to be only available on low-speed (<2MB) serial interfaces, but now, there are the new HWICs (High-Speed WAN Interface Cards) which also support asynchronous mode. To learn more about them please visit http://www.cisco.com/en/US/prod/collateral/modules/ps5949/ps6182/prod_qas0900aecd80274424.html.

Question 5

[am4show have=’p2;’]At which layer of the OSI model does PPP perform?

A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 5

Answer: A[/am4show]

Explanation

Layer 2 includes the popular WAN standards, such as the Point-to-Point Protocol (PPP), High-Level Data-Link Control (HDLC) and Frame Relay protocols.

Question 6

[am4show have=’p2;’]Which PPP subprotocol negotiates authentication options?

A. NCP
B. ISDN
C. SUP
D. LCP
E. DLCI

Answer: D[/am4show]

Explanation

Link Control Protocol (LCP) is a subprotocol within the Point-to-Point Protocol protocol suite that is responsible for link management. During establishment of a PPP communication session, LCP establishes the link, configures PPP options, and tests the quality of the line connection between the PPP client and PPP server. LCP automatically handles encapsulation format options and varies packet sizes over PPP communication links.

LCP also negotiates the type of authentication protocol used to establish the PPP session. Different authentication protocols are supported for satisfying the security needs of different environments.

Other subprotocol within PPP is Network Control Protocol (NCP), which is used to allow multiple Network layer protocols (routed protocols) to be used on a point-to-point connection.

Question 7

[am4show have=’p2;’]Which two options are valid WAN connectivity methods? (Choose two)

A. PPP
B. WAP
C. DSL
D. L2TPv3
E. Ethernet

Answer: A C[/am4show]

Question 8

[am4show have=’p2;’]Refer to the exhibit. Which WAN protocol is being used?

A. ATM
B. HDLC
C. Frame Relay
D. PPP

Answer: C[/am4show]

Explanation

Local Management Interface (LMI) is a signaling standard protocol used between your router (DTE) and the first Frame Relay switch. From the output we learn this interface is sending and receiving LMI messages -> Frame Relay is being used.

Question 9

[am4show have=’p2;’]Refer to the exhibit. The show interfaces serial 0/1 command was issued on the R10-1 router. Based on the output displayed which statement is correct?

A. The cable connected to the serial 0/1 interface of the R10-1 router is a DTE cable.
B. The R10-1 router can ping the router interface connected to the serial 0/1 interface.
C. The clock rate used for interface serial 0/1 of the R10-1 router is 1,544,000 bits per second.
D. The CSU used with the serial 0/1 interface of the R10-1 router has lost connection to the service provider.
E. The interface of the remote router connected to the serial 0/1 interface of the R10-1 router is using the default serial interface encapsulation.

Answer: E[/am4show]

Explanation

From the output, we see the the line “Serial0/1 is up, line protocol is up”. That means the link is good and the interface is functioning normally. Also the encapsulation used on this interface is HDLC -> The other end must use the same encapsulation. Otherwise the line protocol will go down.

Question 10

[am4show have=’p2;’]A network administrator needs to configure a serial link between the main office and a remote location. The router at the remote office is a non-Cisco router. How should the network administrator configure the serial interface of the main office router to make the connection?

A. Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# no shut

B. Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation ppp
Main(config-if)# no shut

C. Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation frame-relay
Main(config-if)# authentication chap
Main(config-if)# no shut

D. Main(config)# interface serial 0/0
Main(config-if)#ip address 172.16.1.1 255.255.255.252
Main(config-if)#encapsulation ietf
Main(config-if)# no shut

Answer: B[/am4show]

Explanation

“The router at the remote office is a non-Cisco router” so we cannot use HDLC which is a Cisco proprietary protocol -> A is not correct (HDLC is the default protocol on Cisco router for serial connection so we don’t need to type any command).

Frame Relay does not support authentication but if we run PPP over Frame Relay then we can use PAP or CHAP. Answer C does not have enough commands for this type of configuration -> C is not correct.

Cisco routers have two kinds of Frame Relay encapsulation: IETF or Cisco. A non-Cisco device does not understand “Frame Relay Cisco encapsulation” so if two routers use different kind of Frame Relay encapsulation, they cannot operate. So if we have a non-Cisco device we have to configure “encapsulation ietf” on both ends so that they can work. But the correct command should be “encapsulation frame-relay ietf” -> D is not correct.

Note: The “encapsulation frame-relay ietf” command uses to encapsulate outgoing frames with IETF. Incoming frames can still be decapsulated even if the interface is configured with “Cisco encapsulation”.

Question 11

[am4show have=’p2;’]Refer to the exhibit:

Assuming that the entire network topology is shown, what is the operational status of the interfaces of R2 as indicated by the command output shown?

A. One interface has a problem.
B. Two interfaces have problems.
C. The interfaces are functioning correctly.
D. The operational status of the interfaces cannot be determined from the output shown.

Answer: C[/am4show]

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

If you are not sure about Frame Relay, please read my Frame Relay tutorial.

Question 1

[am4show have=’p2;’]What can be done to Frame Relay to resolve split-horizon issues?(Choose two)

A. Disable Inverse ARP.
B. Create a full-mesh topology.
C. Develop multipoint subinterfaces.
D. Configure point-to-point subinterfaces.
E. Remove the broadcast keyword from the frame-relay map command.

Answer: B D[/am4show]

Explanation

SPLIT HORIZON: A router never sends information about a route back in same direction which is original information came, routers keep track of where the information about a route came from. Means when router A sends update to router B about any failure network, router B does not send any update for same network to router A in same direction.

Therefore in order to resolve split-horizon issue, we can create a full-mesh topology (a network topology in which there is a direct link between all pairs of nodes) so that all the routers can learn all the routes advertised by the neighbors -> B is correct.

Configuring Point-to-point subinterfaces is a good way to resolve the split-horizon issue because each subinterface is treated as a separate interface so an interface can send and receive information about a route -> D is correct.

Question 2

[am4show have=’p2;’]Which encapsulation type is a Frame Relay encapsulation type that is supported by Cisco routers?

A. IETF
B. ANSI Annex D
C. Q9333-A Annex A
D. HDLC

Answer: A[/am4show]

Explanation

Cisco supports two Frame Relay encapsulation types: the Cisco encapsulation and the IETF Frame Relay encapsulation, which is in conformance with RFC 1490 and RFC 2427. The former is often used to connect two Cisco routers while the latter is used to connect a Cisco router to a non-Cisco router. You can test with your Cisco router when typing the command Router(config-if)#encapsulation frame-relay ? on a WAN link. Below is the output of this command (notice Cisco is the default encapsulation so it is not listed here, just press Enter to use it).

Note: Three LMI options are supported by Cisco routers are ansi, Cisco, and Q933a. They represent the ANSI Annex D, Cisco, and ITU Q933-A (Annex A) LMI types, respectively.

HDLC is a WAN protocol same as Frame-Relay and PPP so it is not a Frame Relay encapsulation type.

Question 3

[am4show have=’p2;’]What are two characteristics of Frame Relay point-to-point subinterfaces? (Choose two)

A. They create split-horizon issues.
B. They require a unique subnet within a routing domain.
C. They emulate leased lines.
D. They are ideal for full-mesh topologies.
E. They require the use of NBMA options when using OSPF.

Answer: B C[/am4show]

Question 4

[am4show have=’p2;’]What is the result of issuing the frame-relay map ip 192.168.1.2 202 broadcast command?

A. defines the destination IP address that is used in all broadcast packets on DLCI 202
B. defines the source IP address that is used in all broadcast packets on DLCI 202
C. defines the DLCI on which packets from the 192.168.1.2 IP address are received
D. defines the DLCI that is used for all packets that are sent to the 192.168.1.2 IP address

Answer: D[/am4show]

Explanation

This command is described in detail at http://www.9tut.com/frame-relay-tutorial/2. If you don’t get this question please read it.

Question 5

[am4show have=’p2;’]What does the frame-relay interface-dlci command configure?

A. local DLCI on the subinterface
B. remote DLCI on the main interface
C. remote DLCI on the subinterface
D. local DLCI on the main interface

Answer: A[/am4show]

Explanation

When configuring on a point-to-point subinterface, the command frame-relay interface-dlci associates the selected point-to-point subinterface with a DLCI. But remember that the DLCI number in this command is the local DLCI. An example of using this command is shown below:

Question 6

[am4show have=’p2;’]What command is used to verify the DLCI destination address in a Frame Relay static configuration?

A. show frame-relay pvc
B. show frame-relay lmi
C. show frame-relay map
D. show frame relay end-to-end

Answer: C[/am4show]

Explanation

An example of the output of “show frame-relay map” command is shown below:

We can see the IP address 172.16.3.1 is associated with the DLCI 100.

Question 7

[am4show have=’p2;’]What occurs on a Frame Relay network when the CIR is exceeded?

A. All TCP traffic is marked discard eligible.
B. All UDP traffic is marked discard eligible and a BECN is sent.
C. All TCP traffic is marked discard eligible and a BECN is sent.
D. All traffic exceeding the CIR is marked discard eligible.

Answer: D[/am4show]

Explanation

Committed information rate (CIR): The minimum guaranteed data transfer rate agreed to by the Frame Relay switch. Frames that are sent in excess of the CIR are marked as discard eligible (DE) which means they can be dropped if the congestion occurs within the Frame Relay network.

Note: In the Frame Relay frame format, there is a bit called Discard eligible (DE) bit that is used to identify frames that are first to be dropped when the CIR is exceeded.

Question 8

[am4show have=’p2;’]What is the purpose of Inverse ARP?

A. to map a known IP address to a MAC address
B. to map a known DLCI to a MAC address
C. to map a known MAC address to an IP address
D. to map a known DLCI to an IP address
E. to map a known IP address to a SPID
F. to map a known SPID to a MAC address

Answer: D[/am4show]

Question 9

[am4show have=’p2;’]What is the advantage of using a multipoint interface instead of point-to-point subinterfaces when configuring a Frame Relay hub in a hub-and-spoke topology?

A. It avoids split-horizon issues with distance vector routing protocols.
B. IP addresses can be conserved if VLSM is not being used for subnetting.
C. A multipoint interface offers greater security compared to point-to-point subinterface configurations.
D. The multiple IP network addresses required for a multipoint interface provide greater addressing flexibility over point-to-point configurations.

Answer: B[/am4show]

Explanation

A main advantage of configuring Frame Relay multipoint compared to point-to-point subinterfaces is we can assign IP addresses on the same subnets/networks to the interfaces of Frame Relay switch, thus saving the subnets/networks you have.

Question 10

[am4show have=’p2;’]Which command allows you to verify the encapsulation type (CISCO or IETF) for a frame relay link?

A. show frame-relay map
B. show frame-relay lmi
C. show inter serial
D. show frame-relay pvc

Answer: A[/am4show]

Explanation

The “show frame-relay map” command displays the current map entries and information about the connections, including encapsulation type.

You can check Table 33 in the following link: http://www.cisco.com/en/US/docs/ios/12_2/wan/command/reference/wrffr4.html#wp1029343

It clearly states there is a Field which can be Cisco or IETF, which “indicates the encapsulation type for this map”. We quote that Table 33 here for your quick reference (you will see what we want to imply in bold):

The “show frame-relay lmi” gives us information about the LMI encapsulation type used by the Frame Relay interface, which can be ANSI, CISCO or Q933a. Therefore it is not what the question requires (CISCO or IETF).

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

If you are not sure about Frame Relay, please read my Frame Relay tutorial.

Question 1

[am4show have=’p2;’]The command show frame-relay map gives the following output:

Serial 0 (up): ip 192.168.151.4 dlci 122, dynamic, broadcast, status defined, active

Which statements represent what is shown? (Choose three)

A. 192.168.151.4 represents the IP address of the remote router
B. 192.168.151.4 represents the IP address of the local serial interface
C. DLC1122 represents the interface of the remote serial interface
D. DLC1122 represents the local number used to connect to the remote address
E. broadcast indicates that a dynamic routing protocol such as RIP v1 can send packets across this PVC
F. active indicates that the ARP process is working

Answer: A D E[/am4show]

Question 2

[am4show have=’p2;’]The output of the show frame-relay pvc command shows ”PVC STATUS=INACTIVE”. What does this mean?

A. The PVC is configured correctly and is operating normally,but no data packets have been detected for more than five minutes.
B. The PVC is configured correctly, is operating normally and is no longer actively seeking the address the remote route.
C. The PVC is configured correctly, is operating normally and is waiting for interesting to trigger a call to the remote router.
D. The PVC is configured correctly on the local switch, but there is a problem on the remote end of the PVC.
E. The PVC is not configured on the switch.

Answer: D[/am4show]

Explanation

The PVC STATUS displays the status of the PVC. The DCE device creates and sends the report to the DTE devices. There are 4 statuses:

+ ACTIVE: the PVC is operational and can transmit data
+ INACTIVE: the connection from the local router to the switch is working, but the connection to the remote router is not available
+ DELETED: the PVC is not present and no LMI information is being received from the Frame Relay switch
+ STATIC: the Local Management Interface (LMI) mechanism on the interface is disabled (by using the “no keepalive” command). This status is rarely seen so it is ignored in some books.

Question 3

[am4show have=’p2;’]What two statistics appear in show frame-relay map output? (Choose two)

A. The number of FECN packets that are received by the router
B. The number of BECN packets that are received by the router
C. The ip address of the local router
D. The value of the local DLCI
E. The status of the PVC that is configured on the router

Answer: D E[/am4show]

Explanation

An example of the output of this command is shown below:

From the output we can see the local DLCI (102 & 103) and the status of the PVC configured on the router (both are defined, active).

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Question 1

[am4show have=’p2;’]Which three of these statements regarding 802.1Q trunking are correct? (Choose three)

A. 802.1Q native VLAN frames are untagged by default.
B. 802.1Q trunking ports can also be secure ports.
C. 802.1Q trunks can use 10 Mb/s Ethernet interfaces.
D. 802.1Q trunks require full-duplex, point-to-point connectivity.
E. 802.1Q trunks should have native VLANs that are the same at both ends.

Answer: A C E[/am4show]

Explanation

Native VLAN frames are carried over the trunk link untagged -> A is correct.

802.1Q trunking ports carry all the traffic of all VLANs so it cannot be the secure ports. A secure port should be only configured to connect with terminal devices (hosts, printers, servers…) -> B is not correct.

The Inter-Switch Link (ISL) encapsulation requires FastEthernet or greater to operate but 802.1q supports 10Mb/s Ethernet interfaces. -> C is correct.

802.1Q supports point-to-multipoint connectivity. Although in Cisco implementation, a “trunk” is considered a point-to-point link but 802.1q encapsulation can be used on an Ethernet segment shared by more than two devices. Such a configuration is seldom needed but is still possible with the disablement of DTP negotiation. -> D is not correct (Reference: http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a008012ecf3.shtml)

The native VLAN that is configured on each end of an 802.1Q trunk must be the same. This is because when a switch receives an untagged frame, it will assign that frame to the native VLAN. If one end is configured VLAN1 as the native VLAN while the other end is configured VLAN2 as the native VLAN, a frame sent in VLAN1 on one side will be received on VLAN2 on the other side -> E is correct.

Question 2

[am4show have=’p2;’]Refer to the exhibit. A technician has configured the FastEthernet 0/1 interface on Sw11 as an access link in VLAN 1. Based on the output from the show vlan brief command issued on Sw12, what will be the result of making this change on Sw11?

A. Only the hosts in VLAN 1 on the two switches will be able to communicate with each other.
B. The hosts in all VLANs on the two switches will be able to communicate with each other.
C. Only the hosts in VLAN 10 and VLAN 15 on the two switches will be able to communicate with each other.
D. Hosts will not be able to communicate between the two switches.

Answer: D[/am4show]

Explanation

Fa0/1 of Switch11 is configured as an access link of VLAN1 so only frames in VLAN1 can communicate through the two switches. But from the output above we see there is no interface belongs to VLAN1 on Switch12 -> no hosts can communicate between the two switches.

Question 3

[am4show have=’p2;’]Refer to the exhibit:

What can be determined about the interfaces of the Main_Campus router from the output shown?

A. The LAN interfaces are configured on different subnets.
B. Interface FastEthernet 0/0 is configured as a trunk.
C. The Layer 2 protocol of interface Serial 0/1 is NOT operational.
D. The router is a modular router with five FastEthernet interfaces.
E. Interface FastEthernet 0/0 is administratively deactivated.

Answer: B[/am4show]

Explanation

We can’t confirm answer B is totally correct but all other answers are wrong so B is the best choice.

+ We only have 1 LAN interface on Main_Campus router with 4 subinterfaces -> answer A is not correct (although it is a bit unclear).
+ The “protocol” column of interface Serial0/1 is up so its Layer 2 is operating correctly -> answer C is not correct.
+ This router has only 1 FastEthernet interface -> answer D is not correct.
+ The “status” column of Fa0/0 is currently “up” so it is operating -> answer E is not correct.

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

If you are not sure about InterVLAN routing, please read my InterVLAN Routing Tutorial (Premium Tutorial)

Question 1

[am4show have=’p2;’]Refer to the exhibit:

Which two statements are true about interVLAN routing in the topology that is shown in the exhibit? (Choose two)

A. Host E and host F use the same IP gateway address.
B. Routed and Switch2 should be connected via a crossover cable.
C. Router1 will not play a role in communications between host A and host D.
D. The FastEthernet 0/0 interface on Router1 must be configured with subinterfaces.
E. Router1 needs more LAN interfaces to accommodate the VLANs that are shown in the exhibit.
F. The FastEthernet 0/0 interface on Router1 and Switch2 trunk ports must be configured using the same encapsulation type.

Answer: D F[/am4show]

Question 2

[am4show have=’p2;’]Refer to the exhibit:

What commands must be configured on the 2950 switch and the router to allow communication between host 1 and host 2? (Choose two)

A. Router(config)#interface fastethernet 0/0
Router(config-if)#ip address 192.168.1.1 255.255.255.0
Router(config-if)#no shut down

B. Router(config)#interface fastethernet 0/0
Router(config-if)#no shutdown
Router(config)#interface fastethernet 0/0.1
Router(config-subif)#encapsulation dot1q 10
Router(config-subif)#ip address 192.168.10.1 255.255.255.0
Router(config-subif)#interface fastethernet 0/0.2
Router(config-subif)#encapsulation dot1q 20
Router(config-subif)#ip address 192.168.20.1 255.255.255.0

C. Router (config)#router eigrp 100
Router(config-router)#network 192.168.10.0
Router(config-router)#network 192.168.20.0

D. Switch1(config)# vlan database
Switch1(config-vlan)# vtp domain XYZ
Switch1(config-vlan)# vtp server

E. Switch1(config)# interface fastEthernet 0/1
Switch1(config-if)# switchport mode trunk

F. Switch1(config)# interface vlan 1
Switch1(config-if)# ip default-gateway 192.168.1.1

Answer: B E[/am4show]

Explanation

The two answers B and E list all the commands needed to configure interVLAN routing. Please notice that Cisco switch 2950, 2960 only support dot1Q trunking so we don’t need to specify which trunking encapsulation to use in this case. For Cisco switches 3550 or above we have to use these commands instead:

Switch3550(config-if)#switchport trunk encapsulation dot1q
Switch3550(config-if)#switchport mode trunk

Question 3

[am4show have=’p2;’]Which three statements are typical characteristics of VLAN arrangements? (Choose three)

A. A new switch has no VLANs configured.
B. Connectivity between VLANs requires a Layer 3 device.
C. VLANs typically decrease the number of collision domains.
D. Each VLAN uses a separate address space.
E. A switch maintains a separate bridging table for each VLAN.
F. VLANs cannot span multiple switches.

Answer: B D E[/am4show]

Explanation

By default, all ports on a new switch belong to VLAN 1 (default & native VLAN). There are also some well-known VLANs (for example: VLAN 1002 for fddi-default; VLAN 1003 for token-ring…) configured by default -> A is not correct.

To communicate between two different VLANs we need to use a Layer 3 device like router or Layer 3 switch -> B is correct.

VLANs don’t affect the number of collision domains, they are the same -> C is not correct. Typically, VLANs increase the number of broadcast domains.
We must use a different network (or sub-network) for each VLAN. For example we can use 192.168.1.0/24 for VLAN 1, 192.168.2.0/24 for VLAN 2 -> D is correct.

A switch maintains a separate bridging table for each VLAN so that it can send frame to ports on the same VLAN only. For example, if a PC in VLAN 2 sends a frame then the switch look-ups its bridging table and only sends frame out of its ports which belong to VLAN 2 (it also sends this frame on trunk ports) -> E is correct.

We can use multiple switches to expand VLAN -> F is not correct.

Question 4

[am4show have=’p2;’]Refer to the exhibit:

C-router is to be used as a “router-on-a-stick” to route between the VLANs. All the interfaces have been properly configured and IP routing is operational. The hosts in the VLANs have been configured with the appropriate default gateway. What can be said about this configuration?

A. These commands need to be added to the configuration:
C-router(config)# router eigrp 123
C-router(config-router)# network 172.19.0.0

B. No further routing configuration is required.

C. These commands need to be added to the configuration:
C-router(config)# router ospf 1
C-router(config-router)# network 172.19.0.0 0.0.3.255 area 0

D. These commands need to be added to the configuration:
C-router(config)# router rip
C-router(config-router)# network 172.19.0.0

Answer: B[/am4show]

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Note: If you are not sure about Spanning Tree Protocol, please read my Spanning Tree Protocol STP tutorial (Premium tutorial).

Question 1

[am4show have=’p2;’]Which term describes a spanning-tree network that has all switch ports in either the blocking or forwarding state?

A. converged
B. redundant
C. provisioned
D. spanned

Answer: A[/am4show]

Explanation

Spanning Tree Protocol convergence (Layer 2 convergence) happens when bridges and switches have transitioned to either the forwarding or blocking state. When layer 2 is converged, root bridge is elected and all port roles (Root, Designated and Non-Designated) in all switches are selected.

Question 2

[am4show have=’p2;’]Refer to the exhibit. Given the output shown from this Cisco Catalyst 2950, what is the reasons that interface FastEthernet 0/10 is not the root port for VLAN 2?

A. This switch has more than one interface connected to the root network segment in VLAN 2.
B. This switch is running RSTP while the elected designated switch is running 802.1d Spanning Tree.
C. This switch interface has a higher path cost to the root bridge than another in the topology.
D. This switch has a lower bridge ID for VLAN 2 than the elected designated switch.

Answer: C[/am4show]

Question 3

[am4show have=’p2;’]Refer to the exhibit. Which switch provides the spanning-tree designated port role for the network segment that services the printers?

A. Switch1
B. Switch2
C. Switch3
D. Switch4

Answer: C[/am4show]

Explanation

First, the question asks what switch services the printers, so it can be Switch 3 or Switch 4 which is connected directly to the Printers.

Next, by comparing the MAC address of Switch 3 and Switch 4 we found that the MAC of Switch 3 is smaller. Therefore the interface connected to the Printers of Switch 3 will become designated interface and the interface of Switch 4 will be blocked.
(Please notice that Switch 1 will become the root bridge because of its lowest priority, not Switch 3)

Question 4

[am4show have=’p2;’]What is one benefit of PVST+?

A. PVST+ supports Layer 3 load balancing without loops.
B. PVST+ reduces the CPU cycles for all the switches in the network.
C. PVST+ allows the root switch location to be optimized per VLAN.
D. PVST+ automatically selects the root bridge location, to provide optimized bandwidth usage.

Answer: C[/am4show]

Explanation

Per VLAN Spanning Tree (PVST) maintains a spanning tree instance for each VLAN configured in the network. It means a switch can be the root bridge of a VLAN while another switch can be the root bridge of other VLANs in a common topology. For example, Switch 1 can be the root bridge for Voice data while Switch 2 can be the root bridge for Video data. If designed correctly, it can optimize the network traffic.

Question 5

[am4show have=’p2;’]Which port state is introduced by Rapid-PVST?

A. learning
B. listening
C. discarding
D. forwarding

Answer: C[/am4show]

Explanation

PVST+ is based on IEEE802.1D Spanning Tree Protocol (STP). But PVST+ has only 3 port states (discarding, learning and forwarding) while STP has 5 port states (blocking, listening, learning, forwarding and disabled). So discarding is a new port state in PVST+.

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Note: If you are not sure about Rapid Spanning Tree Protocol, please read our Rapid Spanning Tree Protocol RSTP Tutorial.

Question 1

[am4show have=’p2;’]Which three statements about RSTP are true? (Choose three)

A. RSTP significantly reduces topology reconvening time after a link failure.
B. RSTP expands the STP port roles by adding the alternate and backup roles.
C. RSTP port states are blocking, discarding, learning, or forwarding.
D. RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.
E. RSTP also uses the STP proposal-agreement sequence.
F. RSTP uses the same timer-based process as STP on point-to-point links.

Answer: A B D[/am4show]

Question 2

[am4show have=’p2;’]Refer to the exhibit:

Why has this switch not been elected the root bridge for VLAN1?

A. It has more than one internee that is connected to the root network segment.
B. It is running RSTP while the elected root bridge is running 802.1d spanning tree.
C. It has a higher MAC address than the elected root bridge.
D. It has a higher bridge ID than the elected root bridge.

Answer: D[/am4show]

Explanation

As we can see from the output above, the priority of the root bridge is 20481 while that of the local bridge is 32769.

Question 3

[am4show have=’p2;’]Which command enables RSTP on a switch?

A. spanning-tree mode rapid-pvst
B. spanning-tree uplinkfast
C. spanning-tree backbonefast
D. spanning-tree mode mst

Answer: A[/am4show]

Question 4

[am4show have=’p2;’]Refer to the exhibit. Which statement is true?

A. The Fa0/11 role confirms that SwitchA is the root bridge for VLAN 20.
B. VLAN 20 is running the Per VLAN Spanning Tree Protocol.
C. The MAC address of the root bridge is 0017.596d.1580.
D. SwitchA is not the root bridge, because not all of the interface roles are designated.

Answer: D[/am4show]

Explanation

Only non-root bridge can have root port. Fa0/11 is the root port so we can confirm this switch is not the root bridge -> A is not correct.

From the output we learn this switch is running Rapid STP, not PVST -> B is not correct.

0017.596d.1580 is the MAC address of this switch, not of the root bridge. The MAC address of the root bridge is 0017.596d.2a00 -> C is not correct.

All of the interface roles of the root bridge are designated. SwitchA has one Root port and 1 Alternative port so it is not the root bridge -> D is correct.

Question 5

[am4show have=’p2;’]Refer to the exhibit. The output that is shown is generated at a switch. Which three of these statements are true? (Choose three)

A. All ports will be in a state of discarding, learning or forwarding.
B. Thirty VLANs have been configured on this switch.
C. The bridge priority is lower than the default value for spanning tree.
D. All interfaces that are shown are on shared media.
E. All designated ports are in a forwarding state.
F. The switch must be the root bridge for all VLANs on this switch.

Answer: A C E[/am4show]

Explanation

From the output, we see that all ports are in Designated role (forwarding state) -> A and E are correct.

The command “show spanning-tree vlan 30″ only shows us information about VLAN 30. We don’t know how many VLAN exists in this switch -> B is not correct.

The bridge priority of this switch is 24606 which is lower than the default value bridge priority 32768 -> C is correct.

All three interfaces on this switch have the connection type “p2p”, which means Point-to-point environment – not a shared media -> D is not correct.

The only thing we can specify is this switch is the root bridge for VLAN 3o but we can not guarantee it is also the root bridge for other VLANs -> F is not correct.

Question 6

[am4show have=’p2;’]Which two states are the port states when RSTP has converged? (choose two)

A. blocking
B. learning
C. disabled
D. forwarding
E. listening

Answer: A D[/am4show]

Explanation

RSTP only has 3 port states that are discarding, learning and forwarding. When RSTP has converged there are only 2 port states left: discarding and forwarding but the answers don’t mention about discarding state so blocking state (answer A) may be considered the best alternative answer.

Question 7

[am4show have=’p2;’]Which two of these statements regarding RSTP are correct? (Choose two)

A. RSTP cannot operate with PVST+.
B. RSTP defines new port roles.
C. RSTP defines no new port states.
D. RSTP is a proprietary implementation of IEEE 802.1D STP.
E. RSTP is compatible with the original IEEE 802.1D STP.

Answer: B E[/am4show]

Question 8

[am4show have=’p2;’]Refer to the exhibit. Each of these four switches has been configured with a hostname, as well as being configured to run RSTP. No other configuration changes have been made. Which three of these show the correct RSTP port roles for the indicated switches and interfaces? (Choose three)

A. SwitchA, Fa0/2, designated
B. SwitchA, Fa0/1, root
C. SwitchB, Gi0/2, root
D. SwitchB, Gi0/1, designated
E. SwitchC, Fa0/2, root
F. SwitchD, Gi0/2, root

Answer: A B F[/am4show]

Explanation

The question says “no other configuration changes have been made” so we can understand these switches have the same bridge priority. Switch C has lowest MAC address so it will become root bridge and 2 of its ports (Fa0/1 & Fa0/2) will be designated ports -> E is incorrect.

Because SwitchC is the root bridge so the 2 ports nearest SwitchC on SwitchA (Fa0/1) and SwitchD (Gi0/2) will be root ports -> B and F are correct.

Now we come to the most difficult part of this question: SwitchB must have a root port so which port will it choose? To answer this question we need to know about STP cost and port cost.

In general, “cost” is calculated based on bandwidth of the link. The higher the bandwidth on a link, the lower the value of its cost. Below are the cost values you should memorize:

SwitchB will choose the interface with lower cost to the root bridge as the root port so we must calculate the cost on interface Gi0/1 & Gi0/2 of SwitchB to the root bridge. This can be calculated from the “cost to the root bridge” of each switch because a switch always advertises its cost to the root bridge in its BPDU. The receiving switch will add its local port cost value to the cost in the BPDU.

In the exhibit you also see FastEthernet port is connecting to GigabitEthernet port. In this case GigabitEthernet port will operate as a FastEthernet port so the link can be considered as FastEthernet to FastEthernet connection.

One more thing to notice is that a root bridge always advertises the cost to the root bridge (itself) with an initial value of 0.

Now let’s have a look at the topology again

SwitchC advertises its cost to the root bridge with a value of 0. Switch D adds 19 (the cost value of 100Mbps link although the port on Switch D is GigabitEthernet port) and advertises this value (19) to SwitchB. SwitchB adds 4 (the cost value of 1Gbps link) and learns that it can reach SwitchC via Gi0/1 port with a total cost of 23. The same process happens for SwitchA and SwitchB learns that it can reach SwitchC via Gi0/2 with a total cost of 38 -> Switch B chooses Gi0/1 as its root port -> D is not correct.

Now our last task is to identify the port roles of the ports between SwitchA & SwitchB. It is rather easy as the MAC address of SwitchA is lower than that of SwitchB so Fa0/2 of SwitchA will be designated port while Gi0/2 of SwitchB will be alternative port -> A is correct but C is not correct.

Below summaries all the port roles of these switches:

+ DP: Designated Port (forwarding state)
+ RP: Root Port (forwarding state)
+ AP: Alternative Port (blocking state)

Question 9

[am4show have=’p2;’]Refer to the exhibit. At the end of an RSTP election process, which access layer switch port will assume the discarding role?

A. Switch3, port fa0/1
B. Switch3, port fa0/12
C. Switch4, port fa0/11
D. Switch4, port fa0/2
E. Switch3, port Gi0/1

Answer: C[/am4show]

Explanation

In this question, we only care about the Access Layer switches (Switch3 & 4). Switch 3 has a lower bridge ID than Switch 4 (because the MAC of Switch3 is smaller than that of Switch4) so both ports of Switch3 will be in forwarding state. The alternative port will surely belong to Switch4.

Switch4 will need to block one of its ports to avoid a bridging loop between the two switches. But how does Switch4 select its blocked port? Well, the answer is based on the BPDUs it receives from Switch3. A BPDU is superior than another if it has:

1. A lower Root Bridge ID
2. A lower path cost to the Root
3. A lower Sending Bridge ID
4. A lower Sending Port ID

These four parameters are examined in order. In this specific case, all the BPDUs sent by Sswitch3 have the same Root Bridge ID, the same path cost to the Root and the same Sending Bridge ID. The only parameter left to select the best one is the Sending Port ID (Port ID = port priority + port index). In this case the port priorities are equal because they use the default value, so Switch4 will compare port index values, which are unique to each port on the switch, and because Fa0/12 is inferior to Fa0/1, Switch4 will select the port connected with Fa0/1 (of Switch3) as its root port and block the other port -> Port fa0/11 of Switch4 will be blocked (discarding role).

If you are still not sure about this question, please read my RSTP tutorial.

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Question 1

[am4show have=’p2;’]Which two are advantages of static routing when compared to dynamic routing? (choose two)

A. Security increases because only the network administrator may change the routing tables.
B. Configuration complexity decreases as network size increases.
C. Routing updates are automatically sent to neighbors.
D. Route summarization is computed automatically by the router.
E. Routing traffic load is reduced when used in stub network links.
F. An efficient algorithm is used to build routing tables using automatic updates.
G. Routing tables adapt automatically to topology changes.

Answer: A E[/am4show]

Explanation

Static routing can only be configured for each route manually so it is more secure than dynamic routing which only needs to declare which networks to run -> A is correct.

Also static route does not use any complex algorithm to find out the best path so no routing updates need to be sent out -> reduce routing traffic load. Static routing is useful especially in stub network links.

Note: Stub network (or stub router) is used to describe a network (or router) that does not have any information about other networks except a default route. This type of network (or router) usually has only one connection to the outside.

Question 2

[am4show have=’p2;’]Which parameter would you tune to affect the selection of a static route as a backup, when a dynamic protocol is also being used?

A. hop count
B. administrative distance
C. link bandwidth
D. link delay
E. link cost

Answer: B[/am4show]

Explanation

By default a static route has the Administrative Distance (AD) of 1, which is always preferred to dynamic routing protocols. In some cases we may want to use dynamic routing protocols and set static routes as a backup route when the “dynamic” routes fail -> we can increase the AD of that static route to a higher value than the AD of the dynamic routing protocols.

Question 3

[am4show have=’p2;’]Which statement is true, as relates to classful or classless routing?

A. RIPV1 and OSPF are classless routing protocols.
B. Classful routing protocols send the subnet mask in routing updates.
C. Automatic summarization at classful boundaries can cause problems on discontigous networks.
D. EIGRP and OSPF are classful routing protocols and summarize routes by default.

Answer: C[/am4show]

Explanation

Discontiguous networks are networks that have subnets of a major network separated by a different major network. Below is an example of discontiguous networks where subnets 10.10.1.0/24 and 10.10.2.0/24 are separated by a 2.0.0.0/8 network.

If we configure automatic summarization at classful boundaries, users on network 10.10.1.0/24 cannot communicate with users on network 10.10.2.0/24.

If you are not clear about automatic summarization please read the last part of this tutorial: http://www.9tut.com/eigrp-routing-protocol-tutorial.

Question 4

[am4show have=’p2;’]A technician pastes the configurations in the exhibit into the two new routers shown. Otherwise, the routers are configured with their default configurations. A ping from Host1 to Host2 fails, but the technician is able to ping the S0/0 interface of R2 from Host1. The configurations of the hosts have been verified as correct. What is the cause of the problem?

A. The serial cable on R1 needs to be replaced.
B. The interfaces on R2 are not configured properly.
C. R1 has no route to the 192.168.1.128 network.
D. The IP addressing scheme has overlapping subnetworks.
E. The ip subnet-zero command must be configured on both routers.

Answer: C[/am4show]

Explanation

Host1 can ping the Serial interface of R2 because R1 has the network of 192.168.1.4/30 as directly connected route. But R1 does not know how to route to the network of Host2 (192.168.1.128/26) so R1 will drop that ping without trying to send it out S0/0 interface. To make the ping work, we have to configure a route pointing to that network (for example: ip route 192.168.1.128 255.255.255.192 s0/0 on R1).

Question 5

[am4show have=’p2;’]Refer to the exhibit. The Lakeside Company has the internetwork in the exhibit. The Administrator would like to reduce the size of the routing table to the Central Router. Which partial routing table entry in the Central router represents a route summary that represents the LANs in Phoenix but no additional subnets?

A – 10.0.0.0 /22 is subnetted, 1 subnet
D 10.0.0.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

B – 10.0.0.0 /28 is subnetted, 1 subnet
D 10.2.0.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

C – 10.0.0.0 /30 is subnetted, 1 subnet
D 10.2.2.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

D – 10.0.0.0 /22 is subnetted, 1 subnet
D 10.4.0.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

E – 10.0.0.0 /28 is subnetted, 1 subnet
D 10.4.4.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

F – 10.0.0.0 /30 is subnetted, 1 subnet
D 10.4.4.4 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

Answer: D[/am4show]

Explanation

All the above networks can be summarized to 10.0.0.0 network but the question requires to “represent the LANs in Phoenix but no additional subnets” so we must summarized to 10.4.0.0 network. The Phoenix router has 4 subnets so we need to “move left” 2 bits of “/24”-> /22 is the best choice -> D is correct.

Question 6

[am4show have=’p2;’]Refer to the exhibit. How will the router handle a packet destined for 192.0.2.156?

A. The router will drop the packet.
B. The router will return the packet to its source.
C. The router will forward the packet via Serial2.
D. The router will forward the packet via either Serial0 or Serial1.

Answer: C[/am4show]

Explanation

From the output we see a line “Gateway of last resort is 192.168.4.1 to network 0.0.0.0”. Gateway of last resort refers to the next-hop router of a router’s current default route. Therefore all the traffic through this router to destination networks not matching any other networks or subnets in the routing table will be sent to 192.168.4.1 (which is on Serial2) -> packet destined for 192.0.2.156 (or an unknown destination) will be forwarded via Serial2.

An weird thing in the output above is the missing of the asterisk mask (*) which represents for the candidate default route. To set the “Gateway of last resort is 192.168.4.1 to network 0.0.0.0” as the output above we can use these commands:

ip route 0.0.0.0 0.0.0.0 192.168.4.1
ip default-network 192.168.4.0

But these commands will create an static routing in the routing table with an asterisk mask. Maybe the output shown above is missing that route.

For more information about the command ip default-network please visit: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094374.shtml.

Question 7

[am4show have=’p2;’]Refer to the exhibit. RTA is configured with a basic configuration. The link between the two routers is operational and no routing protocols are configured on either router. The line shown in the exhibit is then added to router RTA. Should interface Fa0/0 on router RTB shut down, what effect will the shutdown have on router RTA?

A. A route to 172.16.14.0/24 will remain in the RTA routing table.
B. A packet to host 172.16.14.225 will be dropped by router RTA
C. Router RTA will send an ICMP packet to attempt to verify the route.
D. Because router RTB will send a poison reverse packet to router RTA, RTA will remove the route.

Answer: A[/am4show]

Explanation

Static routes remain in the routing table even if the specified gateway becomes unavailable. If the specified gateway becomes unavailable, you need to remove the static route from the routing table manually. However, static routes are removed from the routing table if the specified interface goes down, and are reinstated when the interface comes back up.

Therefore the static route will only be removed from the routing table if the S0/0 interface on RTA is shutdown.

(Reference: http://www.cisco.com/en/US/docs/security/asa/asa84/configuration/guide/route_static.html)

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Note: If you are not sure about OSPF, please read my OSPF tutorial first.

Question 1

[am4show have=’p2;’]

R1 routing commands:
ip route 0.0.0.0 0.0.0.0 serial0/0
router ospf 1
network 172.16.100.0 0.0.0.3 area 0
network 172.16.100.64 0.0.0.63 area 0
network 172.16.100.128 0.0.0.31 area 0
default-information originate

Assuming that all router interfaces are operational and correctly configured, that OSPF has been correctly configured on router R2, how will the default route configured on R1 affect the operation of R2?

A. Any packet destined for a network that is not directly connected to router R1 will be dropped.
B. Any packet destined for a network that is not referenced in the routing table of router R2 will be directed to R1. R1 will then send that packet back to R2 and a routing loop will occur.
C. Any packet destined for a network that is not directly connected to router R2 will be dropped immediately.
D. Any packet destined for a network that is not directly connected to router R2 will be dropped immediately because of the lack of a gateway on R1.

Answer: B[/am4show]

Explanation

First, notice that the more-specific routes will always be favored over less-specific routes regardless of the administrative distance set for a protocol. In this case, because we use OSPF for three networks (172.16.100.0 0.0.0.3, 172.16.100.64 0.0.0.63, 172.16.100.128 0.0.0.31) so the packets destined for these networks will not be affected by the default route.

The default route configured on R1 “ip route 0.0.0.0 0.0.0.0 serial0/0″ will send any packet whose destination network is not referenced in the routing table of router R1 to R2, it doesn’t drop anything so answers A, B and C are not correct. D is not correct too because these routes are declared in R1 and the question says that “OSPF has been correctly configured on router R2″, so network directly connected to router R2 can communicate with those three subnetworks.

As said above, the default route configured on R1 will send any packet destined for a network that is not referenced in its routing table to R2; R2 in turn sends it to R1 because it is the only way and a routing loop will occur.

Question 2

[am4show have=’p2;’]What information does a router running a link-state protocol use to build and maintain its topological database? (Choose two)

A. hello packets
B. SAP messages sent by other routers
C. LSAs from other routers
D. beacons received on point-to-point links
E. routing tables received from other link-state routers
F. TTL packets from designated routers

Answer: A C[/am4show]

Explanation

Link-state protocol uses hello packets to discover neighbors and establish adjacencies. After that, the routers begin sending out LSAs to every neighbor (each received LSA is copied and forwarded to every neighbor except the one that sent the LSA)

Question 3

[am4show have=’p2;’]Which two statements describe the process identifier that is used in the command to configure OSPF on a router? (Choose two)

Router(config)# router ospf 1

A. All OSPF routers in an area must have the same process ID.
B. Only one process number can be used on the same router.
C. Different process identifiers can be used to run multiple OSPF processes
D. The process number can be any number from 1 to 65,535.
E. Hello packets are sent to each neighbor to determine the processor identifier.

Answer: C D[/am4show]

Question 4

[am4show have=’p2;’]What is the default administrative distance of OSPF?

A. 90
B. 100
C. 110
D. 120

Answer: C[/am4show]

Explanation

The Administrative Distances (AD) of popular routing protocols are listed below:

Question 5

[am4show have=’p2;’]Refer to the exhibit. The network is converged. After link-state advertisements are received from Router_A, what information will Router_E contain in its routing table for the subnets 208.149.23.64 and 208.149.23.96?

A. 208.149.23.64[110/13] via 190.173.23.10, 00:00:00:07, FastEthernet0/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, FastEthernet0/0

B. 208.149.23.64[110/1] via 190.173.23.10, 00:00:00:07, Serial1/0
208.149.23.96[110/3] via 190.173.23.10, 00:00:00:16, FastEthernet0/0

C. 208.149.23.64[110/13] via 190.173.23.10, 00:00:00:07, Serial1/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, Serial1/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, FastEthernet0/0

D. 208.149.23.64[110/13] via 190.173.23.10, 00:00:00:07, Serial1/0
208.149.23.96[110/13] via 190.173.23.10, 00:00:00:16, Serial1/0

Answer: A[/am4show]

Explanation

Router_E learns two subnets subnets 208.149.23.64 and 208.149.23.96 via Router_A through FastEthernet interface. The interface cost is calculated with the formula 10⁸ / Bandwidth. For FastEthernet it is 10⁸ / 100 Mbps = 10⁸ / 100,000,000 = 1. Therefore the cost is 12 (learned from Router_A) + 1 = 13 for both subnets -> B is not correct.

The cost through T1 link is much higher than through T3 link (T1 cost = 10⁸ / 1.544 Mbps = 64; T3 cost = 10⁸ / 45 Mbps = 2) so surely OSPF will choose the path through T3 link -> Router_E will choose the path from Router_A through FastEthernet0/0, not Serial1/0 -> C & D are not correct.

In fact, we can quickly eliminate answers B, C and D because they contain at least one subnet learned from Serial1/0 -> they are surely incorrect.

Question 6

[am4show have=’p2;’]What are three characteristics of the OSPF routing protocol? (Choose three)

A. It converges quickly.
B. OSPF is a classful routing protocol.
C. It uses cost to determine the best route.
D. It uses the DUAL algorithm to determine the best route.
E. OSPF routers send the complete routing table to all directly attached routers.
F. OSPF routers discover neighbors before exchanging routing information.

Answer: A C F[/am4show]

Explanation

OSPF is a link-state routing protocol so it converges more quickly than distance-vector protocol. OSPF uses cost to determine the best route. The popular formula to calculate OSPF cost is: cost = 10⁸ / Bandwidth [ in kbps] (in fact the formal formula is: cost = reference bandwidth / configured bandwidth of interface in kbps. On Cisco routers, the reference bandwidth defaults to 100000 kbps)

Question 7

[am4show have=’p2;’]

The internetwork infrastructure of company XYZ consists of a single OSPF area as shown in the graphic. There is concern that a lack of router resources is impeding internetwork performance.

As part of examining the router resources the OSPF DRs need to be known.

All the router OSPF priorities are at the default and the router IDs are shown with each router.

Which routers are likely to have been elected as DR? (Choose two)

A. Corp-1
B. Corp-2
C. Corp-3
D. Corp4
E. Branch-1
F. Branch-2

Answer: D F[/am4show]

Explanation

There are 2 segments on the topology above which are separated by Corp-3 router. Each segment will have a DR so we have 2 DRs.

To select which router will become DR they will compare their router-IDs. The router with highest (best) router-ID will become DR. The router-ID is chosen in the order below:

+ The highest IP address assigned to a loopback (logical) interface.

+ If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen.

In this question, the IP addresses of loopback interfaces are not mentioned so we will consider IP addresses of all active router’s physical interfaces. Router Corp-4 (10.1.40.40) & Branch-2 (10.2.20.20) have highest “active” IP addresses so they will become DRs.

Question 8

[am4show have=’p2;’]Which parameter or parameters are used to calculate OSPF cost in Cisco routers?

A. Bandwidth, Delay and MTU
B. Bandwidth
C. Bandwidth and MTU
D. Bandwidth, MTU, Reliability, Delay and Load

Answer: B[/am4show]

Explanation

The well-known formula to calculate OSPF cost is

Cost = 10⁸ / Bandwidth

so B is the correct answer.

Question 9

[am4show have=’p2;’]Refer to the exhibit:

Assume that all of the router interfaces are operational and configured correctly. How will router R2 be affected by the configuration of R1 that is shown in the exhibit?

A. Router R2 will not form a neighbor relationship with R1.
B. Router R2 will obtain a full routing table, including a default route, from R1.
C. R2 will obtain OSPF updates from R1, but will not obtain a default route from R1.
D. R2 will not have a route for the directly connected serial network, but all other directly connected networks will be present, as well as the two networks connected to R1.

Answer: B[/am4show]

Explanation

The default-information originate command advertises a default route to other routers, telling something like “please send me your unknown traffic”. So in this case, besides a full routing table, R2 will also receive a default route from R1 -> B is correct.

Note: But in this question, the static route should be “ip route 0.0.0.0 0.0.0.0 serial0/1″ (not serial0/0), that may cause a routing loop.

Question 10

[am4show have=’p2;’]Which commands are required to properly configure a router to run OSPF and to add network 192.168.16.0/24 to OSPF area 0? (Choose two)

A. Router(config)# router ospf 0
B. Router(config)# router ospf 1
C. Router(config)# router ospf area 0
D. Router(config-router)# network 192.168.16.0 0.0.0.255 0
E. Router(config-router)# network 192.168.16.0 0.0.0.255 area 0
F. Router(config-router)# network 192.168.16.0 255.255.255.0 area 0

Answer: B E[/am4show]

Explanation

In the router ospf command, the ranges from 1 to 65535 so o is an invalid number -> B is correct but A is not correct.

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Note: If you are not sure about OSPF, please read my OSPF tutorial first.

Question 1

[am4show have=’p2;’]Which command is used to display the collection of OSPF link states?

A. show ip ospf link-state
B. show ip ospf Isa database
C. show ip ospf neighbors
D. show ip ospf database

Answer: D[/am4show]

Explanation

The output of the “show ip ospf database” is shown below:

From the output above we can see LSA Type 1 (Router Link State) and LSA Type 3 (Summary Net Link State).

Question 2

[am4show have=’p2;’]What are two drawbacks of implementing a link-state routing protocol? (Choose two)

A. the sequencing and acknowledgment of link-state packets
B. the requirement for a hierarchical IP addressing scheme for optimal functionality
C. the high volume of link-state advertisements in a converged network
D. the high demand on router resources to run the link-state routing algorithm
E. the large size of the topology table listing all advertised routes in the converged network

Answer: B D[/am4show]

Question 3

[am4show have=’p2;’]

The internetwork infrastructure of company XYZ consists of a single OSPF area as shown in the graphic.

There is concern that a lack of router resources is impeding internetwork performance.

As part of examining the router resources the OSPF DRs need to be known.

All the router OSPF priorities are at the default and the router IDs are shown with each router.

Which routers are likely to have been elected as DR? (Choose two)

A. Corp-1
B. Corp-2
C. Corp-3
D. Corp4
E. Branch-1
F. Branch-2

Answer: D F[/am4show]

Explanation

There are 2 segments on the topology above which are separated by Corp-3 router. Each segment will have a DR so we have 2 DRs.

To select which router will become DR they will compare their router-IDs. The router with highest (best) router-ID will become DR. The router-ID is chosen in the order below:

+ The highest IP address assigned to a loopback (logical) interface.

+ If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen.

In this question, the IP addresses of loopback interfaces are not mentioned so we will consider IP addresses of all active router’s physical interfaces. Router Corp-4 (10.1.40.40) & Branch-2 (10.2.20.20) have highest “active” IP addresses so they will become DRs.

Question 4

[am4show have=’p2;’]What is the default maximum number of equal-cost paths that can be placed into the routing of a Cisco OSPF router?

A. 16
B. 2
C. unlimited
D. 4

Answer: D[/am4show]

Explanation

The default number of equal-cost paths that can be placed into the routing of a Cisco OSPF router is 4. We can change this default value by using “maximum-paths” command:

Router(config-router)#maximum-paths 2

Note: Cisco routers support up to 16 equal-cost paths

Question 5

[am4show have=’p2;’]RouterD# show ip interface brief

Given the output for this command, if the router ID has not been manually set, what router ID will OSPF use for this router?

A. 10.1.1.2
B. 10.154.154.1
C. 172.16.5.1
D. 192.168.5.3

Answer: C[/am4show]

Explanation

The highest IP address of all loopback interfaces will be chosen -> Loopback 0 will be chosen as the router ID.

Question 6

[am4show have=’p2;’]Refer to the exhibit. Which two statements are true about the loopback address that is configured on RouterB? (Choose two)

A. It ensures that data will be forwarded by RouterB.
B. It provides stability for the OSPF process on RouterB.
C. It specifies that the router ID for RouterB should be 10.0.0.1.
D. It decreases the metric for routes that are advertised from RouterB.
E. It indicates that RouterB should be elected the DR for the LAN.

Answer: B C[/am4show]

Explanation

A loopback interface never comes down even if the link is broken so it provides stability for the OSPF process (for example we use that loopback interface as the router-id) -> B is correct.

The router-ID is chosen in the order below:

+ The highest IP address assigned to a loopback (logical) interface.
+ If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen.

-> The loopback interface will be chosen as the router ID of RouterB -> C is correct.

Question 7

[am4show have=’p2;’]Refer to the exhibit. The network associate is configuring OSPF on the Core router. All the connections to the branches should be participating in OSPF. The link to the ISP should NOT participate in OSPF and should only be advertised as the default route. What set of commands will properly configure the Core router?

A. Core(config-router)#default-information originate
Core(config-router)#network 10.0.0.0 0.255.255.255 area 0
Core(config-router)#exit
Core(config)#ip route 0.0.0.0 0.0.0.0 10.10.2.14

B. Core(config-router)#default-information originate
Core(config-router)#network 10.10.2.13 0.0.0.242 area 0
Core(config-router)#exit
Core(config)#ip route 0.0.0.0 0.0.0.0 10.10.2.14

C. Core(config-router)#default-information originate
Core(config-router)#network 10.10.2.16 0.0.0.15 area 0
Core(config-router)#exit
Core(config)#ip route 0.0.0.0 0.0.0.0 10.10.2.14

D. Core(config-router)#default-information originate
Core(config-router)#network 10.10.2.32 0.0.0.31 area 0
Core(config-router)#exit
Core(config)#ip route 0.0.0.0 0.0.0.0 10.10.2.14

Answer: C[/am4show]

Explanation

The question states that the link to ISP should not participate in OSPF -> answers A, B are not correct.

In answer D, the “network 10.10.2.32 0.0.0.31 area 0” does not cover the IP address of S0/0.103 (10.10.2.21) -> D is not correct.

The default-information originate command advertises a default route to other routers, telling something like “please send me your unknown traffic”. So in this case, besides a full routing table, other routers will also receive a default route from Core router.
But please notice that Core router needs to have a default route in its routing table. That is why the command “ip route 0.0.0.0 0.0.0.0 10.10.2.14” is added to Core router. By adding the “always” (after “default-information originate” command) the default route will be advertised even if there is no default route in the routing table of router Core.

Question 8

[am4show have=’p2;’]

A network associate has configured OSPF with the command:
City(config-router)# network 192.168.12.64 0.0.0.63 area 0

After completing the configuration, the associate discovers that not all the interfaces are participating in OSPF.
Which three of the interfaces shown in the exhibit will participate in OSPF according to this configuration statement? (Choose three)

A. FastEthernet0/0
B. FastEthernet0/1
C. Serial0/0
D. Serial0/1.102
E. Serial0/1.103
F. Serial0/1.104

Answer: B C D[/am4show]

Explanation

The “network 192.168.12.64 0.0.0.63″ equals to network 192.168.12.64/26. This network has:
+ Increment: 64 (/26= 1111 1111.1111 1111.1111 1111.1100 0000)
+ Network address: 192.168.12.64
+ Broadcast address: 192.168.12.127
Therefore all interface in the range of this network will join OSPF -> B C D are correct.

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Note: If you are not sure about EIGRP, please read my EIGRP tutorial.

Question 1

[am4show have=’p2;’]What does a router do if it has no EIGRP feasible successor route to a destination network and the successor route to that destination network is in active status?

A. It routes all traffic that is addressed to the destination network to the interface indicated in the routing table.
B. It sends a copy of its neighbor table to all adjacent routers.
C. It sends a multicast query packet to all adjacent neighbors requesting available routing paths to the destination network.
D. It broadcasts Hello packets to all routers in the network to re-establish neighbor adjacencies.

Answer: C[/am4show]

Explanation

When a router has no EIGRP feasible successor and the successor route to that destination network is in active status (the successor route is down, for example) a route recomputation occurs. A route recomputation commences with a router sending a query packet to all neighbors. Neighboring routers can either reply if they have feasible successors for the destination or optionally return a query indicating that they are performing a route recomputation. While in Active state, a router cannot change the next-hop neighbor it is using to forward packets. Once all replies are received for a given query, the destination can transition to Passive state and a new successor can be selected.

(Reference: http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f07.shtml#rout_states)

Question 2

[am4show have=’p2;’]Which statements are true about EIGRP successor routes? (Choose two)

A. A successor route is used by EIGRP to forward traffic to a destination.
B. Successor routes are saved in the topology table to be used if the primary route fails.
C. Successor routes are flagged as ‘active* in the routing table.
D. A successor route may be backed up by a feasible successor route.
E. Successor routes are stored in the neighbor table following the discovery process.

Answer: A D[/am4show]

Question 3

[am4show have=’p2;’]Which type of EIGRP route entry describes a feasible successor?

A. a backup route, stored in the routing table
B. a primary route, stored in the routing table
C. a backup route, stored in the topology table
D. a primary route, stored in the topology table

Answer: C[/am4show]

Explanation

Feasible successor is a route whose Advertised Distance is less than the Feasible Distance of the current best path. A feasible successor is a backup route, which is not stored in the routing table but stored in the topology table.

Question 4

[am4show have=’p2;’]Refer to the exhibit. Based on the exhibited routing table, how will packets from a host within the 192.168.10.192/26 LAN be forwarded to 192.168.10.1?

A. The router will forward packets from R3 to R2 to R1
B. The router will forward packets from R3 to R1
C. The router will forward packets from R3 to R1 to R2
D. The router will forward packets from R3 to R2 to R1 AND from R3 to R1

Answer: D[/am4show]

Explanation

From the routing table we learn that network 192.168.10.0/30 is learned via 2 equal-cost paths (192.168.10.9 &192.168.10.5) -> traffic to this network will be load-balancing.

Question 5

[am4show have=’p2;’]Refer to the exhibit. Given the output from the show ip eigrp topology command, which router is the feasible successor?

A.

10.1.0.3 (Serial0), from 10.1.0.3, Send flag is 0x0
   Composite metric is (46866176/46354176), Route is Internal 
   Vector metric:
     Minimum bandwidth is 56 Kbit
     Total delay is 45000 microseconds
     Reliability is 255/255
     Load is 1/255
     Minimum MTU is 1500
     Hop count is 2 

B.

10.0.0.2 (Serial0.1), from 10.0.0.2, Send flag is 0x0
   Composite metric is (53973248/128256), Route is Internal 
   Vector metric:
     Minimum bandwidth is 48 Kbit
     Total delay is 25000 microseconds
     Reliability is 255/255
     Load is 1/255
     Minimum MTU is 1500
     Hop count is 1

C.

10.1.0.1 (Serial0), from 10.1.0.1, Send flag is 0x0
   Composite metric is (46152000/41640000), Route is Internal Vector metric:
     Minimum bandwidth is 64 Kbit 
     Total delay is 45000 microseconds 
     Reliability is 255/255 
     Load is 1/255 
     Minimum MTU is 1500
     Hop count is 2

D.

10.1.1.1 (SerialO.1), from 10.1.1.1, Send flag is 0x0
   Composite metric is (46763776/46251776), Route is External 
   Vector metric:
     Minimum bandwidth is 56 Kbit
     Total delay is 41000 microseconds
     Reliability is 255/255
     Load is 1/255
     Minimum MTU is 1500
     Hop count is 2

Answer: B[/am4show]

Explanation

First we must notice that all the 4 answers are parts of the “show ip eigrp topology” output. As you can see, there are 2 parameters in the form of [FD/AD] in each answer. For example answer C has [46152000/41640000], it means that the FD of that route is 46152000 while the AD is 41640000.

To become a feasible successor, a router must meet the feasibility condition:

“To qualify as a feasible successor, a router must have an AD less than the FD of the current successor route“

In four answer above, only answer B has an AD of 128256 and it is smaller than the FD of the current successor route (41152000) so it is the feasible successor -> B is correct.

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Question 1

[am4show have=’p2;’]Refer to the exhibit. What three actions will the switch take when a frame with an unknown source MAC address arrives at the interface? (Select three)

A. Send an SNMP trap.
B. Send a syslog message.
C. Increment the Security Violation counter.
D. Forward the traffic.
E. Write the MAC address to the startup-config.
F. Shut down the port.

Answer: A B C[/am4show]

Explanation

Notice that the Violation Mode is Restrict. In this mod, when the number of port secure MAC addresses reaches the maximum limit allowed on the port, packets with unknown source addresses are dropped. You have to remove the secure mac-addresses below the maximum allowed number in order to learn a new MAC or allowing a host on the port. Also a SNMP trap is sent, a syslog message is logged in the syslog server and the violation counter increases.

(Reference: http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/port_sec.html)

Question 2

[am4show have=’p2;’]Which protocol is an open standard protocol framework that is commonly used in VPNs, to provide secure end-to-end communications?

A. RSA
B. L2TP
C. IPsec
D. PPTP

Answer: C[/am4show]

Explanation

One of the most widely deployed network security technologies today is IPsec over VPNs. It provides high levels of security through encryption and authentication, protecting data from unauthorized access.

Question 3

[am4show have=’p2;’]Refer to the exhibit. Which of these correctly describes the results of port security violation of an unknown packet?

A. port enabled; unknown packets dropped; no SNMP or syslog messages
B. port enabled; unknown packets dropped; SNMP or syslog messages
C. port disabled; no SNMP or syslog messages
D. port disabled; SNMP or syslog messages

Answer: D[/am4show]

Explanation

The default violation mode is shutdown, which will shutdown the port when the maximum number of secure MAC addresses is exceeded. It also sends an SNMP trap, logs a syslog message, and increments the violation counter.

The three violation modes are listed below:

+protect – When the number of secure MAC addresses reaches the limit allowed on the port, packets with unknown source addresses are dropped until you remove a sufficient number of secure MAC addresses or increase the number of maximum allowable addresses. You are not notified that a security violation has occurred.

+restrict – When the number of secure MAC addresses reaches the limit allowed on the port, packets with unknown source addresses are dropped until you remove a sufficient number of secure MAC addresses or increase the number of maximum allowable addresses. In this mode, you are notified that a security violation has occurred. Specifically, an SNMP trap is sent, a syslog message is logged, and the violation counter increments.

+shutdown – In this mode, a port security violation causes the interface to immediately become error-disabled, and turns off the port LED. It also sends an SNMP trap, logs a syslog message, and increments the violation counter. When a secure port is in the error-disabled state, you can bring it out of this state by entering the errdisable recovery cause psecure-violation global configuration command, or you can manually re-enable it by entering the shutdown and no shutdown interface configuration commands. This is the default mode.

(Reference: http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/port_sec.html)

Question 4

[am4show have=’p2;’]The following configuration is applied to a Layer 2 Switch:

interface fastethernet 0/4
switchport mode access
switchport port-security
switchport port-security mac-address 0000.1111.1111
switchport port-security maximum 2

What is the result of the above configuration being applied to the switch?

A. A host with a mac address of 0000.1111.1111 and up to two other hosts can connect to FastEthernet 0/4 simultaneously
B. A host with a mac address of 0000.1111.1111 and one other host can connect to FastEthernet 0/4 simultaneously
C. Violating addresses are dropped and no record of the violation is kept
D. The switch can send an SNMP message to the network management station
E. The port is effectively shutdown

Answer: B[/am4show]

Question 5

[am4show have=’p2;’]What can be done to secure the virtual terminal interfaces on a router? (Choose two)

A. Administratively shut down the interface.
B. Physically secure the interface.
C. Create an access list and apply it to the virtual terminal interfaces with the access-group command.
D. Configure a virtual terminal password and login process.
E. Enter an access list and apply it to the virtual terminal interfaces using the access-class command.

Answer: D E[/am4show]

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Note: If you are not sure about IPv6, please read my IPv6 tutorial.

Question 1

[am4show have=’p2;’]Which command enables IPv6 forwarding on a Cisco router?

A. ipv6 local
B. ipv6 host
C. ipv6 unicast-routing
D. ipv6 neighbor

Answer: C[/am4show]

Explanation

An example of configuring RIPng (similar to RIPv2 but is used for IPv6) is shown below:

Router(config)#ipv6 unicast-routing (Enables the forwarding of IPv6 unicast datagrams globally on the router)
Router(config)#interface fa0/0
Router(config-if)#ipv6 rip 9tut enable (9tut is the process name of this RIPng)

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Here you will find answers to ICND 2 – Drag And Drop Questions

Question 1

[am4show have=’p2;’]Two offices are displayed below

You work as a network technician at 9tut. Study the exhibit carefully. The company has a main office in Los Angeles and a satellite office in Boston. The offices are connected through two Cisco routers. The Boston satellite office is connected through the R2 router s0 interface to the Los Angeles office R1 router s1 interface. R1 has two local area networks. Boston users receive Internet access through the R1 router. Drag the boxes on the top to complete the goal on the left.

Answer:

[/am4show]1) Prevent all users from outside the enterprise network from accessing the server: permit ip 192.168.35.0 0.0 0.255 host 192.168.35.66
2) Block a user from R1 e0 network from accessing the server: deny ip 192.168.35.55 0.0.0.0 host 192.168.35.66
3) Block only the users attached to the e0 interface of the R2 router from accessing the server: deny ip 192.168.35.16 0.0.0.15 host 192.168.35.66

Question 2

[am4show have=’p2;’]You are configuring the localhost/nitunetwp office. In particular the host C, with the IP address 192.168.125.34/27, needs to be configured so that it cannot access hosts outside its own subnet. You decide to use the following command:
access-list 100 deny protocol address mask any

You are required to fill in the protocol, address, and mask in this command using the choices below:

Answer:

[/am4show]1) protocol: ip
2) address: 192.168.125.34
3) mask: 0.0.0.0

Explanation

The syntax of extended access-list:

access-list 100-199 {permit|deny} {ip|tcp|udp|icmp} source source-mask [lt|gt|eq|neq] [source-port] destination dest-mask [lt|gt|eq|neq] [dest-port]

By telling the router to drop traffic originated from host C (source), we can guarantee that host C can just communicate with hosts inside its own subnet (because this kind of traffic does not need to pass the router and will not be prevented).

Question 3

[am4show have=’p2;’]Exhibit:

Study the exhibit carefully. You need to match output lines in the exhibit with the proper OSI layer. One line will not be used.

Answer:

[/am4show]Data Link Layer:

+ Encapsulation PPP
+ Line protocol is up

Physical Layer:

+ Serial 1/0 is up
+ Hardware is CD2430 in sync mode

Question 4

[am4show have=’p2;’]You work as a network administrator for your corporation, your boss is interested in switch ports. Match the options to the appropriate switch ports

Answer:

[/am4show]Access Port:

+ carries traffic for a single VLAN
+ uses a straight-through cable to connect a device
+ connects an end-user workstation to a switch

Trunk Port:

+ carries traffic for a multiple VLAN
+ Facilitates interVLAN communications when connected to a Layer 3 device
+ uses 802.1q to identify traffic from different VLANs

Question 5

[am4show have=’p2;’]Below is the configuration of the R1 router:

R1(config)# ip route 0.0.0.0 0.0.0.0 192.168.1.1
R1(config)# ip route 10.1.0.0 255.255.255.0 192.168.2.2
R1(config)# ip route 10.1.0.0 255.255.0.0 192.168.3.3

Drag each destination IP address on the top to its correct next hop address at the bottom.

Answer:

[/am4show]Next hop 192.168.1.1:
+ 10.2.1.3
+ 10.6.8.4

Next hop 192.168.2.2:
+ 10.1.0.14
+ 10.1.0.123

Next hop 192.168.3.3:
+ 10.1.1.10
+ 10.1.4.6

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Here you will find answers to ICND 2 – Drag and Drop Questions Part 2

Question 1

[am4show have=’p2;’]Match the categories with the appropriate router output lines.

Answer:

[/am4show]1) Port operational: Serial0/1 is up, line protocol is up
2) Layer 2 problem: Serial0/1 is up, line protocol is down
3) Layer 1 problem: Serial0/1 is down, line protocol is down
4) Port disabled: Serial0/1 is administratively down, line protocol is down

Explanation:

A simple way to find out which layer is having problem is to remember this rule: “the first statement is for Layer 1, the last statement is for Layer 2 and if Layer 1 is down then surely Layer 2 will be down too”, so you have to check Layer 1 before checking Layer 2. For example, from the output “Serial0/1 is up, line protocol is down” we know that it is a layer 2 problem because the first statement (Serial0/1 is up) is good while the last statement (line protocol is down) is bad. For the statement “Serial0/1 is down, line protocol is down”, both layers are down so the problem belongs to Layer 1.

There is only one special case with the statement “…. is administratively down, line protocol is down”. In this case, we know that the port is currently disabled and shut down by the administrators.

Question 2

[am4show have=’p2;’]The above provides some descriptions, while the below provides some routing protocols. Drag the above items to the proper locations.

Answer:

[/am4show]EIGRP:

+ has a default administrative distance of 90
+ is vendor-specific

OSPF:

+ uses cost as its metric
+ elects a DR on each multiaccess network

Question 3

[am4show have=’p2;’]Drag the term on the left to its definition on the right (not all options are used)

Answer:

[/am4show]+ poison reverse: A router learns from its neighbor that a route is down and the router sends an update back to the neighbor with an infinite metric to that route
+ LSA: The packets flooded when a topology change occurs, causing network routers to update their topological databases and recalculate routes
+ split horizon: This prevents sending information about a routeback out the same interface that originally learned about the route
+ holddown timer: For a given period, this causes the router to ignore any updates with poorer metrics to a lost network

Question 4

[am4show have=’p2;’]

Answer:

[/am4show]+ holddown timer: prevents a router from improperly reinstating a route from a regular routing update
+ split horizon: prevents information about a route from being sent in the direction from which the route was learned
+ defining a maximum: prevents invalid updates from looping the internetwork indefinitely
+ route poisoning: causes a routing protocol to advertise an infinite metric for a failed route
+ triggered update: decreases convergence time by immediately sending route information in response to a topology change

[am4show have=’p2;’]

Premium Member: You can test your knowledge with these questions first via this link.

[/am4show]

Here you will find answers to Drag and Drop Questions – Part 3

Question 1

[am4show have=’p2;’]Drag item on left to match item on right

Answer:
[/am4show]+ Point to Point Advantage: Quality
+ Point to Point Disadvantage: Limited Flexibility
+ Circuit Switched Advantage: Cost
+ Circuit Switched Disadvantage: Low speed
+ Packet Switch Advantage: Efficient
+ Packet Switch Disadvantage: More Complex

Question 2

[am4show have=’p2;’]Place the Spanning-Tree Protocol port state on its functions (not all options on the left are used)

Answer:

[/am4show]+ Populating the MAC address table but not forwarding data frames: LEARNING
+ Sending and receiving data frames: FORWARDING
+ Preparing to forward data frames without populating the MAC address table: LISTENING
+ Preventing the use of looped paths: BLOCKING

Question 3

[am4show have=’p2;’]As a CCNA candidate, you need to know EIGRP very well.
Which tables of EIGRP route information are held in RAM and maintained through the use of hello and update packets?

Please choose two appropriate tables and drag the items to the proper locations.

Answer:

[/am4show]Neighbor Table
Topology Table

You can try the EIGRP Troubleshooting Simulator here:

+ EIGRP Troubleshooting Simulator

and read the explanation here.

To provide for fault tolerance, many networks implement redundant paths between devices using multiple switches. However, providing redundant paths between segments causes packets to be passed between the redundant paths endlessly. This condition is known as a bridging loop.

(Note: the terms bridge, switch are used interchangeably when discussing STP)

To prevent bridging loops, the IEEE 802.1d committee defined a standard called the spanning tree algorithm (STA), or spanning tree protocol (STP). Spanning-Tree Protocol is a link management protocol that provides path redundancy while preventing undesirable loops in the network. For an Ethernet network to function properly, only one active path can exist between two stations.

Let’s see a situation when there is no loop-avoidance process in operation. Suppose you have two switches connected with redundant links. One switch connected to PC A and the other switch connected to PC B.

Now PC A wants to talk to PC B. It then sends a broadcast, say an Address Resolution Protocol (ARP) to find out where the location of PC B, the green arrow shows a broadcast frame sent by PC A.

When the switch A receives a broadcast frame, it forwards that frame to all ports except the port where it receives the request -> SwA forwards that ARP frame out of fa0/0 and fa0/1 ports.

Read more…

In the previous VLAN tutorial we learned how to use VLAN to segment the network and create “logical” broadcast domains. In this tutorial we will learn about InterVLAN Routing.

What is InterVLAN routing?

As we learned, devices within a VLAN can communicate with each other without the need of Layer 3 routing. But devices in separate VLANs require a Layer 3 routing device to communicate with one another. For example, in the topology below host A and B can communicate with each other without a router in the same VLAN 10; host C and D can communicate in the same VLAN 20. But host A can’t communicate with host C or D because they are in different VLANs.

To allow hosts in different VLANs communicate with each other, we need a Layer 3 device (like a router) for routing:

The routing traffic from one VLAN to another VLAN is called InterVLAN routing.

Read more…

You can try the OSPF Neighbor Simulator here:

+ OSPF Neighbor Simulator

Supported command:

You can try the Show Configuration Simulator here:
+ Show Configuration Simulator

Note: This sim is for the ICND1 100-105 exam. The “show running-config” and “show startup-config” commands are disabled because of the requirement of this sim.

You can try the Security Testlet Simulator here:

+ Security Testlet Simulator

Dear our readers,

First we really want to say thanks to all who are reading 9tut.net. Thank for the time you spent with us, your comments and opinions.

Our team had a conversation about 9tut.net. We all love to write tutorials, explanations and answer questions for our readers. We love to support you to achieve your targets but our time is limited. So recently new questions, tutorials have not been added to 9tut. It is sad to say but if we keep this situation, 9tut cannot develop anymore. After that talk, we decided that 9tut should have a premium membership part to fully support you.

We really hope to continue bringing you amazing stuffs in the networking field. But without the fund, 9tut and other sites cannot operate. With your support, we can continue offering ICND1 & 2 tutorials and questions more frequently. We also try our best to keep the fee as small as possible (currently $19 per 30 days or $35 per 60 days) while bringing you our best support.

Become a premium member allows you to access:

+ Flash-based questions to check your knowledge with each topic of ICND1 & 2.
+ Flash-based questions on all topics of ICND1 & 2 to help you fully prepare for the ICND1 & 2 exams. See example.
+ Practice popular ICND1 & 2 sims with our simulators.

We wish you to understand our situation now.

Thanks and regards,

9tut team.

Note:
+ There is only one type of Premium Membership on 9tut.net which is used for both ICND1 & 2 exams.
+ The Premium Membership lasts 30 days from the date you make the payment.
+ The Premium Membership on 9tut.net is only dedicated for the ICND1 & 2 exams, not the CCNA 200-125 exam.
+ The Premium Membership fee is non-recurring so you will not be charged automatically when your Premium Membership expires. If you want to extend your account, you have to do manually.

If you have any questions or problems, please send an email to support@9tut.net. We will help you solve the problem!

The ICND1&2 exams have been retired so we temporarily close the Premium Membership on this site!

The new ICND2 200-101 exam is coming to replace the old ICND2 640-816 exam. This exam is new so it will need some time to put up materials for this exam. In the meantime, we create the “Share your (new) ICND2 Experience” for everyone to share their experience after taking this exam.

Note: The last date to take the ICND2 exam is Sep-30-2013.

Please share with us your experience after taking the new ICND2 200-101 exam, your materials, the way you learned, your recommendations…

The new ICND1 100-101 exam is coming to replace the old ICND1 640-822 exam. This exam is new so it will need some time to put up materials for this exam. In the meantime, we create the “Share your (new) ICND1 Experience” for everyone to share their experience after taking this exam.

Note: The last date to take the ICND1 exam is Sep-30-2013.

Please share with us your experience after taking the new ICND1 100-101 exam, your materials, the way you learned, your recommendations…

Here you will find answers to WAN Questions

Question 1

As a network technician, you must know the various layers of the OSI model. At which layers of the OSI Model do Wide Area Networks operate in? (Choose two)

A. Physical Layer
B. Datalink Layer
C. Network Layer
D. Session Layer
E. Transport Layer
F. Presentation Layer
G. Application Layer

Answer: A B

Explanation

Frame Relay is a high-performance WAN protocol that operates at the physical and data link layers of the OSI reference model.

Question 2

Network equipment supporting the use of flow control mechanisms has been recently installed in the network. What is the purpose of flow control in a data network?

A. It ensures that data is retransmitted if an acknowledgment is not received.
B. It reassembles segments in the correct order on the destination device.
C. It provides a mechanism for the receiver to control the transmission speed.
D. It regulates the size of each datagram segment.
E. All of the above are functions of flow control

Answer: C

Explanation

Flow control is the process that control the rates at which data is transferred between two endpoints, enabling a receiving device to signal congestion to a sending device, which allows for the sending device to temporarily halt transmission, alleviating congestion at the receiving device.

Question 3

You are a network administrator working in the communication company. One day, you find that the encapsulation has been altered by someone on a synchronous serial line and this new configuration is not the optimal one. So you attempt to return the encapsulation to the default. Which measure will you take to reach this goal?

A. Issue the shutdown then no shutdown commands to reset the encapsulation on the interface.
B. Reboot the router and allow it to reload the configuration.
C. Configure the interface for HDLC encapsulation.
D. Change the encapsulation to ARPA.

Answer: C

Explanation

We can’t use the “shutdown” & “no shutdown” commands to reset the encapsulation because it doesn’t affect the encapsulation type -> A is not correct.

Reboot the router and reload the configuration can solve this problem but other configuration will be erased too -> not a good choice.

The question asks “attempt to return the encapsulation to the default” and the default encapsulation on a Cisco router is HDLC so we can configure the interface for HDLC encapsulation -> C is the correct.

D is not correct as ARPA is not the default WAN encapsulation of a Cisco router. ARPA is the standard Ethernet version 2.0 encapsulation.

Question 4

During your interview for a network administrator job, your interviewer gives you some statements to judge. The following options are all related to the configuration of a serial link on a Cisco router. You should point out which one is the correct. What is your answer?

A. The clock rate command is a requirement for DCE interfaces.
B. If the clock rate command is configured, then the bandwidth command is required.
C. If the bandwidth command is configured, then the clock rate command is required.
D. Cisco routers are DCE devices.

Answer: A

Explanation

The purpose of DCE equipment is to provide clocking and switching services in a network. Clock rate doesn’t have a default value so we have to configure it manually (while bandwidth does have a default value). Cisco routers can be configured as DTE or DCE devices.

Question 5

As a network technician, you should know how to gain information from the exhibit. According to the command output displayed in the following exhibit, please point out the correct description about interface Serial 0/0/0.

Exhibit

A. The configuration is incomplete, which will cause the interface status to be “Serial0/0/0 is down, line protocol is down”
B. The interface is using Cisco HDLC for layer 2 encapsulation.
C. The configuration is incomplete, which will cause the interface status to be “Serial0/0/0 is up, line protocol is down”.
D. A ping to the remote address 209.165.200.226 will be successful.

Answer: B

Explanation

The configuration is correct and the “no shutdown” command was used (because we don’t see a “shutdown” line in the output) so we can see at least “Serial0/0/0 is up” -> A is not correct.

Although the configuration is correct but we don’t know if this interface is connected with another router or not. If it is connected with another interface (on another router) and that interface is up, we will see the “Serial0/0/0 is up, line protocol is up”. Otherwise we will see “Serial0/0/0 is up, line protocol is down” -> we can’t guarantee answer C is correct.

Answer D is the same with C because we don’t know if the remote interface 209.165.200.226 exists (and turned up) or not.

For WAN interface (serial interface), the default layer 2 encapsulation is HDLC -> B is correct.

Question 6

You work as a network administrator. You study the exhibits carefully. The corporate office and branch office have been attached through two non-Cisco routers over a highly reliable WAN connection over a year. A new Cisco router has been installed to replace the hardware at the branch location. Since the installation, IP communication cannot be verified across the link.

Given the output on router R1, what could be a logical first step to take to resolve this problem?

A. Ensure an exact match between the bandwidth setting on Router1 and Router2
B. Change the encapsulation on Router1 to PPP.
C. Change the bandwidth setting on Router1 to match the actual line speed
D. Verify successful DCE communication between the two sites.
E. Verify Layer1 communication on the Router1 Serial0/0 interface

Answer: B

Explanation

HDLC is a Cisco proprietary protocol so we can’t use it when connecting to a non-Cisco router. PPP is the standard protocol that is widely supported and used by many ISPs.

Question 7

From the choices shown above, which port can be used for a WAN T1 connection?

A. Console
B. Serial 0
C. AUI
D. BRI
E. None of the other alternatives apply

Answer: B

Explanation

The console port is intended for local administrative access from an ASCII terminal or a computer using a terminal emulator.

Serial ports support WAN T1 connection.

Attachment Unit Interface (AUI) ports are designed to connect to an external transceiver for conversion to a specific media type (such as twisted pair, coax, or fiber). AUI can transfer only 1 bit at a time.

BRI ports are used for ISDN services (mostly voice).

Question 8

A WAN connection is shown below:

Based on this diagram, which two devices can be used to complete the connection between the WAN router at the customer site and the service provider? (Choose two)

A. CSU/DSU
B. modem
C. WAN switch
D. ATM switch
E. Frame Relay switch
F. ISDN TA

Answer: A B

Explanation

A modem or CSU/DSU can provide clock rate so it can be used for the topology above.

The Channel Service Unit (CSU) can echo loopback signals from the phone company for testing purposes.

The Data Service Unit (DSU) manages line control, and converts input and output between RS-232C, RS-449, or V.35 frames from the LAN and the time-division multiplexed (TDM) DSX frames on the T-1 line. The DSU provides a modem-like interface between the computer as Data Terminal Equipment (DTE) and the CSU.

Here you will find answers to STP Questions

If you are not sure about STP, please read my Spanning Tree Protocol tutorial first.

Question 1

Which switch will be chosen as root bridge and why?

A. Sw-B, because it has the highest MAC address
B. Sw-A, because it has the lowest MAC address
C. Sw-C, because it has the lowest priority
D. Sw-D, because it has the highest priority

Answer: C

Explanation

The bridge with the lowest bridge ID will become the root bridge. The bridge ID = Priority + MAC so the lowest priority will be chosen first. If all switches’ priorities all equal then their MAC will be compared (the lowest is the best).

Question 2

Spanning Tree Protocol has created a loop-free logical topology in the network that is pictured. How many ports have been placed in the blocking mode?

A. two
B. none
C. three
D. one
E. four

Answer: A

Explanation

The best way to solve this question is to suppose that one of these switches is the root switch (bridge). For example, if we choose S2 the root bridge and all of its ports will be in forwarding state (so that they are not blocked).

Also suppose that S1 has higher priority than S3 -> the port on S3 connected to S1 will be blocked.

The most difficult problem is that how can we know which port on S4 will be in blocking state. Well, it depends on the Sending Port ID on S4 (Port ID = port priority + port index). If using default values, the default port priority’s value is the same, so S4 will compare port index values, which are unique to each port on the switch. One more time, we suppose S4 connects to S1 via Fa0/1 and S4 connects to S3 via Fa0/2. Because Fa0/2 is inferior to Fa0/1, S4 will select the port connected with Fa0/1 as its root port and block the other port.

Question 3

What is the way that Spanning Tree Protocol prevents switching loops based on the exhibit provided?

A. STP shuts down S3 to eliminate the switching loops.
B. STP identifies cables that must be disconnected to eliminate the redundant paths.
C. STP load balances traffic evenly across the redundant links.
D. STP places ports into the blocking state to disable the redundant paths.
E. STP allows the switches to communicate with a router that makes the traffic forwarding decisions.

Answer: D

Question 4

The following network was designed to provide reliability through redundancy.

Both of the IDF switches, S3 and S4, are in connection with both of the MDF switches, S1 and S2. A loop-free switching environment is nedded, which configuration scenario will achieve this?

A. Spanning Tree Protocol should be running on all switches.
B. Spanning Tree Protocol should be running only on the root bridge.
C. Spanning Tree Protocol is not needed in this network.
D. Spanning Tree Protocol should be running on only the MDF switches S1 and S2.

Answer: A

Question 5

Which two values are used by Spanning Tree Protocol to elect a root bridge? (Choose two)

A. Amount of RAM
B. Bridge priority
C. IOS version
D. IP address
E. MAC address
F. Speed of the links

Answer: B E

Question 6

Which two of these statements regarding RSTP are correct? (Choose two)

A. RSTP cannot operate with PVST+.
B. RSTP defines new port roles.
C. RSTP defines no new port states.
D. RSTP is a proprietary implementation of IEEE 802.1 D STP.
E. RSTP is compatible with the original IEEE 802.1 D STP.

Answer: B E

Question 7

Which switch would STP choose to become the root bridge in the selection process?

A. 32768: 11-22-33-44-55-66
B. 32768: 22-33-44-55-66-77
C. 32769:11-22-33-44-55-65
D. 32769: 22-33-44-55-66-78

Answer: A

Here you will find answers to VTP & VLAN Questions

If you are not sure about VTP, please read my VTP tutorial and VLAN tutorial

Question 1

A network administrator is explaining VTP configuration to a new technician.
What should the network administrator tell the new technician about VTP configuration? (Choose three)

A. A switch in the VTP client mode cannot update its local VLAN database.
B. A trunk link must be configured between the switches to forward VTP updates.
C. A switch in the VTP server mode can update a switch in the VTP transparent mode.
D. A switch in the VTP transparent mode will forward updates that it receives to other switches.
E. A switch in the VTP server mode only updates switches in the VTP client mode that have a higher VTP revision number.
F. A switch in the VTP server mode will update switches in the VTP client mode regardless of the configured VTP domain membership.

Answer: A B D

Question 2

ALSwitch1# show running-config
«output omitted»
interface FastEthernet0/24 no ip address
«output omitted»
ALSwitch1# show interfaces FastEthernet0/24 switchport
Name: Fa0/24
Switchport: Enable
Administrative Mode: static access
Operation Mode: static access
Administrative Trunking Encapsulation: dot1q
Operation Trunking Encapsulation: native
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Operation private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL

Protected: false

Voice VLAN: none (Inactive)
Aplliance trust: none

Switch port FastEthernet 0/24 on ALSwitch1 will be used to create an IEEE 802.1 Q-compliant trunk to another switch.

What is the reason the trunk does not form, even though the proper cabling has been attached?

A. VLANs have not been created yet.
B. An IP address must be configured for the port.
C. The port is currently configured for access mode.
D. The correct encapsulation type has not been configured.
E. The no shutdown command has not been entered for the port.

Answer: C

Question 3

Which statements describe two of the benefits of VLAN Trunking Protocol? (Choose two)

A. VTP allows routing between VLANs.
B. VTP allows a single switch port to carry information to more than one VLAN.
C. VTP allows physically redundant links while preventing switching loops.
D. VTP simplifies switch administration by allowing switches to automatically share VLAN configuration information.
E. VTP helps to limit configuration errors by keeping VLAN naming consistent across the VTP domain.
F. VTP enhances security by preventing unauthorized hosts from connecting to the VTP domain.

Answer: D E

Explanation

VLAN Trunking Protocol (VTP) is used to ensure that all switches in a given group, or VTP domain, have the same information about the VLANs that are present in that domain. When VTP is turned on, switches will automatically share its VLANs information to other switches (which are in the same domain) by VTP updates.

Question 4

Which two link protocols are used to carry multiple VLANs over a single link? (Choose two)

A. VTP
B. 802.1q
C. IGP
D. ISL
E. 802.3u

Answer: B D

Explanation

The Inter-Switch Link (ISL) and 802.1Q protocols are used to establish trunk links carrying traffic for multiple VLANs.

Question 5

Which three of these statements regarding 802.1Q trunking are correct? (Choose three)

A. 802.1Q native VLAN frames are untagged by default.
B. 802.1Q trunking ports can also be secure ports.
C. 802.1Q trunks can use 10 Mb/s Ethernet interfaces.
D. 802.1Q trunks require full-duplex, point-to-point connectivity.
E. 802.1Q trunks should have native VLANs that are the same at both ends.

Answer: A C E

Explanation

Native VLAN frames are carried over the trunk link untagged -> A is correct.

802.1Q trunking ports carry all the traffic of all VLANs so it cannot be the secure ports. A secure port should be only configured to connect with terminal devices (hosts, printers, servers…) -> B is not correct.

The Inter-Switch Link (ISL) encapsulation requires FastEthernet or greater to operate but 802.1q supports 10Mb/s Ethernet interfaces. -> C is correct.

802.1Q supports point-to-multipoint connectivity. Although in Cisco implementation, a “trunk” is considered a point-to-point link but 802.1q encapsulation can be used on an Ethernet segment shared by more than two devices. Such a configuration is seldom needed but is still possible with the disablement of DTP negotiation. -> D is not correct (Reference: http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a008012ecf3.shtml)

The native VLAN that is configured on each end of an 802.1Q trunk must be the same. This is because when a switch receives an untagged frame, it will assign that frame to the native VLAN. If one end is configured VLAN1 as the native VLAN while the other end is configured VLAN2 as the native VLAN, a frame sent in VLAN1 on one side will be received on VLAN2 on the other side -> E is correct.

Here you will find answers to RIP Questions

Note: If you are not sure about RIP, please read my RIP tutorial

Question 1

What are two characteristics of RIPv2? (Choose two)

A.classful routing protocol
B. variable-length subnet masks
C. broadcast addressing
D. manual route summarization
E. uses SPF algorithm to compute path

Answer: B D

Question 2

Router_1# show ip protocols
Routing Protocol is “rip”
Sending updates every 30 seconds, next due in 8 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set

After a RIP route is marked invalid on Router_1, how much time will elapse before that route is removed from the routing table?

A. 30 seconds
B. 60 seconds
C. 90 seconds
D. 180 seconds
E. 240 seconds

Answer: B

Explanation

The invalid and flush timers start at the same time and run concurrently. So after a RIP route is marked invalid, it will take 240 – 180 = 60 seconds for that route to be removed from the routing table.

Question 3

Which three statements are correct about RIP version 2? (Choose three)

A. It has the same maximum hop count as version 1.
B. It uses broadcasts for its routing updates.
C. It is a classless routing protocol.
D. It has a lower default administrative distance than RIP version 1.
E. It supports authentication.
F. It does not send the subnet mask in updates.

Answer: A C E

Question 4

HQ(config)# router rip
HQ(config-router)# network 172.16.0.0
HQ(config-router)# exit
HQ(con£ig)# ip route 172.16.15.0 255.255.255.0 172.16.18.2 150

Assuming that the routing protocol for the entire network is RIP, and the RIP is configured with its default settings. You properly configure all links and all these links are functioning normally.

Regarding the network described which of the following statements are true? (Choose two)

A. The HQ router will prefer to use its S0 interface to reach E1 of the Branch router.
B. The HQ will prefer to use its BRIO interface to reach E1 on the Branch router.
C. The HQ BRI0 interface will be used to reach the Branch E1 network in the event the S0 link fails.
D. The HQ S0 interface will be used to reach the Branch E1 network in the event the BRI0 link fails.

Answer: A C

Explanation

The HQ router is configured with both static and RIP to reach 172.16.15.0/24 network so it has to use the Administrative Distance of each route to decide which route should it forward the packet to. The static route “ip route 172.16.15.0 255.255.255.0 172.16.18.2 150” is configured with an AD of 150 but the default AD of RIP route is 120 so the RIP path will be favored over static route.

Question 5

Which statement about RIPng is true?

A. RIPng allows for routes with up to 30 hops.
B. RIPng is enabled on each interface separately.
C. RIPng uses broadcasts to exchange routes.
D. There can be only one RIPng process per router.

Answer: B

Explanation

The Routing Information Protocol next generation (RIPng) is an interior gateway protocol (IGP) that uses a distance-vector algorithm to determine the best route to a destination, using the hop count as the metric. RIPng is a routing protocol that exchanges routing information used to compute routes and is intended for Internet Protocol version 6 (IPv6)-based networks.

RIPng is enabled on each interface separately. Below is an example:

R1(config)#ipv6 router rip 9tut //name the process RIPng 9tut
R1(config-rtr)#exit
R1(config)#interface E0/0
R1(config-if)#ipv6 rip 9tut enable //run RIPng 9tut process on E0/0

Question 6

A medium-sized company has a Class C IP address. It has two Cisco routers and one non-Cisco router.
All three routers are using RIP version 1.
The company network is using the block of 198.133.219.0/24.
The company has decided it would be a good idea to split the network into three smaller subnets and create the option of conserving addresses with VLSM.

What is the best course of action if the company wants to have 40 hosts in each of the three subnets?

A. Convert all the routers to EIGRP and use 198.133.219.32/27,198.133.219.64/27, and 198.133.219.92/27 as the new subnetworks.
B. Maintain the use of RIP version 1 and use 198.133.219.32/27,198.133.219.64/27, and 198.133.219.92/27 as the new subnetworks.
C. Convert all the routers to EIGRP and use 198.133.219.64/26,198.133.219.128/26, and 198.133.219.192/26 as the new subnetworks.
D. Convert all the routers to RIP version 2 and use 198.133.219.64/26,198.133.219.128/26, and 198.133.219.192/26 as the new subnetworks.
E. Convert all the routers to OSPF and use 198.133.219.16/28,198.133.219.32/28, and 198.133.219.48/28 as the new subnetworks.
F. Convert all the routers to static routes and use 198.133.219.16/28,198.133.219.32/28, and 198.133.219.48/28 as the new subnetworks.

Answer: D

Question 7

The network shown in the exhibit is running the RIPv2 routing protocol. The network has converged, and the routers in this network are functioning properly.

The FastEthernet0/0 interface on R1 goes down. In which two ways will the routers in this network respond to this change? (Choose two)

A. All routers will reference their topology database to determine if any backup routes to the 192.168.1.0 network are known.
B. Routers R2 and R3 mark the route as inaccessible and will not accept any further routing updates from R1 until their hold-down timers expire.
C. Because of the split-horizon rule, router R2 will be prevented from sending erroneous information to R1 about connectivity to the 192 168.1.0 network.
D. When router R2 learns from R1 that the link to the 192.168.1.0 network has been lost, R2 will respond by sending a route back to R1 with an infinite metric to the 192.168.1.0 network.
E. R1 will send LSAs to R2 and R3 informing them of this change, and then all routers will send periodic updates at an increased rate until the network again converges.

Answer: C D

Question 8

What is the default routing update period for RIPv2?

A. 15 seconds
B. 30 Seconds
C. 180 Seconds
D. 240 Seconds

Answer: B

Question 9

What two things will a router do when running a distance vector routing protocol? (Choose two)

A. Send periodic updates regardless of topology changes.
B. Send entire routing table to all routers in the routing domain.
C. Use the shortest-path algorithm to the determine best path.
D. Update the routing table based on updates from their neighbors.
E. Maintain the topology of the entire network in its database.

Answer: A D

Here you will find answers to EIGRP Questions

Note: If you are not sure about EIGRP, please read my EIGRP tutorial

Question 1

A router has learned three possible routes that could be used to reach a destination network.
One route is from EIGRP and has a composite metric of 20514560. Another route is from OSPF with a metric of 782. The last is from RIPv2 and has a metric of 4.

Which route or routes will the router install in the routing table?

A. the OSPF route
B. the EIGRP route
C. the RIPv2 route
D. all three routes
E. the OSPF and RIPv2 routes

Answer: B

Explanation

Regardless of the metric value, EIGRP has the lowest Administrative Distance (AD) so it will be used and routes learned from EIGRP will be installed in the routing table. Some popular ADs are listed below:

+ Static route: 1
+ RIPv1 & RIPv2: 120
+ IGRP & EIGRP: 90
+ OSPF: 110

Question 2

HQ_Router# show ip protocols

Routing Protocol is “eigrp 109”
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
EIGRP maximum hopcount 100
EIGRP maximum metric variance 1
Redistributing: eigrp 109
Automatic network summarization is in effect
Automatic address summarization: 20.0.0.0/0 for FastEthernet0/1
Summarizing with metric 28160 172.30.0.0/16 for FastEthernet0/0
Summarizing with metric 28160
Maximum path: 4
Routing for Networks:
20.0.0.0
172.30.0.0
192.160.1.0
Routing Information Sources:
Gateway Distance Last Update
20.10.10.2 90 260796
172.30.10.2 90 454765
Distance: internal 90 external 170

How many paths can the EIGRP routing process use to forward packets from HQ_Router to a neighbor router?

A. two equal-cost paths
B. two unequal-cost paths
C. three equal-cost paths
D. three unequal-cost paths
E. four equal-cost paths
F. four unequal-cost paths

Answer: E

Explanation

Because the “EIGRP maximum metric variance” is 1 so only equal-cost paths are used.
The “Maximum path” is 4 so EIGRP can use up to 4 paths to forward packets.

Therefore EIGRP can only use four equal-cost paths -> E is correct.

Notice: This question has another version with “EIGRP maximum metric variance” is set to a value greater than 1 than the answer should be “four unequal-cost paths” can be used.

Question 3

Fabrikant Incorporated is a worldwide finance provider. The network uses EIGRP as its routing protocol throughout the corporation. The network administrator does not understand the convergence of EIGRP. Using the output of the show ip eigrp topology all-links command, answer the administrators questions:

Switch1# show ip eigrp topology all-links

Which three EIGRP routes will be installed for the 172.20.3.128 /25 and 172.20.2.0/24 networks? (choose three)

A. 172.20.3.128 /25 [90/28160] via 172.20.1.2 01:26:35. FastEthernet0/2
B. 172.20.3.128 /25 [90/30720] via 172.20.3.2 01:26:35. FastEthernet0/3
C. 172.20.3.128 /25 [90/30720] via 172.20.10.2 01:26:35. FastEthernet0/1
D. 172.20.2.0 /24 [90/30720] via 172.20.10.2 02:10:11. FastEthernet0/1
E. 172.20.2.0 /24 [90/28160] via 172.20.10.2 02:10:11. FastEthernet0/1
F. 172.20.2.0 /24 [90/33280] via 172.20.3.2 02:10:11. FastEthernet0/1

Answer: B C D

Explanation

There is a similar question posted at http://www.digitaltut.com/route-eigrp-simlet. Please read the explanation there and try to answer this question.

Question 4 (same question as question 3)

Switch1# show ip eigrp topology all-links

Which three networks does the Switch1 device have feasible successors for? (Choose three)

A. 172.20.10.0 /30
B. 172.20.1.0 /24
C. 172.20.2.0 /24
D. 172.20.3.0 /25
E. 172.20.3.128/25
F. 10.69.0.0/24

Answer: A C F

Question 5

A network administrator is troubleshooting an EIGRP problem on a router and needs to confirm the IP addresses of the devices with which the router has established adjacency. The retransmit interval and the queue counts for the adjacent routers also need to be checked.

What command will display the required information?

A. Router# show ip eigrp topology
B. Router# show ip eigrp interfaces
C. Router# show ip eigrp adjacency
D. Router# show ip eigrp neighbors

Answer: D

Explanation

Below is an example of the “show ip eigrp neighbors” command (from 9tut.com)

Question 6

As a Cisco technician, you need to know EIGRP protocol very well. Which of the following is true about EIGRP successor routes? (Choose two)

A. A successor route is used by EIGRP to forward traffic to a destination.
B. Successor routes are saved in the topology table to be used if the primary route fails.
C. Successor routes are flagged as “active” in the routing table.
D. A successor route may be backed up by a feasible successor route.
E. Successor routes are stored in the neighbor table following the discovery process.

Answer: A D

Question 7

Problems may occur when a routing protocol tries to identify the next hop in discontinuous networks in the IP addressing scheme. But some routing protocols may minimize the effects of the problems.

Which are these routing protocols? (Choose three)

A. EIGRP
B. VLSM
C. OSPF
D. RIP v2

Answer: A C D

Explanation

Classless routing protocols can be used in discontinuous networks as they do send the subnet mask in their updates so Variable Length Subnet Masks (VLSMs) are supported.

Question 8

Glencoe#show ip protocol
Routing Protocol is “eigrp 478”
— output omitted —
Redistributing: eigrp 478
Automatic network summarization is not in effect
Maximum path: 4
Routing for Networks:
172.26.168.128/26
172.26.169.0/26
Routing Information Sources:
Gateway Distance Last Update
172.26.168.129 90 01:01:59
Distance: internal 90 external 170

The EIGRP configuration in the Glencoe router uses a single network statement.
From the output shown in the graphic, which network statement would advertise these networks in EIGRP?

A. network 172.26.168.128 area 478
B. network 172.26.0.0
C. network 172.26.168.0 area 478
D. network 172.26.168.128 0.0.0.127

Answer: B

Question 9

What will a router do if it does not have EIGRP feasible successor route to a destination network and the successor route to that destination network is in active status?

A. It broadcasts Hello packets to all routers in the network to re-establish neighbor adjacencies.
B. It routes all traffic that is addressed to the destination network to the interface indicated in the routing table.
C. It sends a multicast query packet to all adjacent neighbors requesting available routing paths to the destination network.
D. It sends a copy of its neighbor table to all adjacent routers.

Answer: C

Question 10

The company uses EIGRP as the routing protocol.

R3# show ip route
Gateway of last resort is not set
192 168.10.0/24 is variably subnetted, 6 subnets, 2 masks
D 192.168. 10.64/26 [90/2195456] via 192.168.10.9, 00:03:31, Serial0/0
D 192.168.10.0/30 [90/2681856] via 192.168.10.9, 00:03:31, Serial0/0
C 192.168.10.4/30 is directly connected, Serial 0/1
C 192.168.10.8/30 is directly connected, Serial 0/0
C 192.168.10.192/26 is directly connected, FastEthernet0/0
D 192.168.10.128/26 [90/2195456] via 192.168.10.5,00:03 31, Serial 0/1

What path will packets take from a host on 192.168.10.192/26 network to a host on the LAN attached to router R1?

A. The path of the packets will be R3 to R2 to R1.
B. The path of the packets will be R3 to R1 to R2.
C. The path of the packets will be both R3 to R2 to R1 and R3 to R1.
D. The path of the packets will be R3 to R1.

Answer: D

Explanation

From the line “D 192.168. 10.64/26 [90/2195456] via 192.168.10.9, 00:03:31, Serial0/0″ we can see the IP address 192.168.10.9 belongs to network 192.168.10.8/30 and this network is between R1 and R3 -> Packet from 192.168.10.192/26 network destined to a host on the LAN attached to router R1 will go directly from R3 to R1.

Here you will find answers to EIGRP Questions – Part 2

Note: If you are not sure about EIGRP, please read my EIGRP tutorial

Question 1

Which two statements are true regarding EIGRP? (Choose two)

A. Passive routes are in the process of being calculated by DUAL
B. EIGRP supports VLSM, route summarization, and routing update authentication.
C. EIGRP exchanges full routing table information with neighboring routers with every update.
D. If the feasible successor has a higher advertised distance than the successor route, it becomes the primary route.
E. A query process is used to discover a replacement for a failed route if a feasible successor is not identified from the current routing information.

Answer: B E

Question 2

The following are four types of EIGRP route entries. Which of them describes a feasible successor?

A. a backup route, stored in the routing table
B. a primary route, stored in the topology table
C. a primary route, stored in the routing table
D. a backup route, stored in the topology table

Answer: D

Explanation

EIGRP builds and maintains three tables:
+ Neighbor table: lists directly connected routers running EIGRP with which this router has an adjacency
+ Topology table: lists all routes learned from each EIGRP neighbor -> the feasible successors are stored here!
+ Routing table: lists all best routes from the EIGRP topology table and other routing processes -> only successors are stored here.

Question 3

Below is the output of a router.

Gateway of last resort is not set

192.168.25.0 /30 is subnetted, 4 subnets
D 192.168.25.20 [90/2681856] via 192.168.15.5, 00:00:10, Serial0/1
D 192.168.25.16 [90/1823638] via 192.168.15.5, 00:00:50, Serial0/1
D 192.168.25.24 [90/3837233] via 192.168.15.5, 00:05:23, Serial0/1
D 192.168.25.28 [90/8127323] via 192.168.15.5, 00:06:45, Serial0/1
C 192.168.15.4/30 is directly connected, Serial0/1
C 192.168.2.0/24 is directly connected, FastEthernet0/0

Which address and mask combination represents a summary of the routes learned by EIGRP?

A. 192.168.25.0 255.255.255.240
B. 192.168.25.28 255.255.255.240
C. 192.168.25.16 255.255.255.252
D. 192.168.25.16 255.255.255.240
E. 192.168.25.28 255.255.255.252
F. 192.168.25.0 255.255.255.252

Answer: D

Explanation

From the output above, EIGRP learned 4 routes and we need to find out the summary of them:
+ 192.168.25.16
+ 192.168.25.20
+ 192.168.25.24
+ 192.168.25.28

-> The increment should be: 28 – 16 = 12 but 12 is not an exponentiation of 2 so we must choose 16 (2⁴). Therefore the subnet mask is /28 (=1111 1111.1111 1111.1111 1111.1111 0000) = 255.255.255.240

So the best answer should be 192.168.25.16 255.255.255.240

Question 4

Enhanced Interior Gateway Routing Protocol – (EIGRP) is a Cisco proprietary routing protocol loosely based on their original IGRP. A router has EIGRP configured as the only routing protocol.

How does EIGRP respond if there is no feasible successor route to a destination network and the successor route fails?

A. It immediately sends its entire routing table to its neighbors.
B. EIGRP sends a Hello packet to the DR to inform it of the route failure.
C. It automatically forwards traffic to a fallback default route until a new successor route is found.
D. It sends queries out to neighbors until a new successor route is found.
E. It places the route in holddown until LSA updates inform it of a new route to the network.

Answer: D

Explanation

EIGRP sends a query when a route is lost and the feasible route (for that path) does not exist in the topology table

Question 5

Router# show ip eigrp topology 10.0.0.5 255.255.255.255

IP-EIGRP topology entry for 10.0.0.5/32 State is Passive, Query origin flag is 1, 1 Successor(s), FD is 41152000

Given the output from the show ip eigrp topology command, which router is the feasible successor?

A. Router A.
10.1.0.1 (serial0), from 10.1.0.1 composite
metric is 46152000/41640000
B. Router B.
10.0.0.2 (serial0.1), from 10.0.0.2
composite metric is 53973240/120256
C. Router C.
10.1.0.3 (serial0), from 10.1.0.3
composite metric is 46866176/46354176
D. Router D.
10.1.1.1 (serial0.1), from 10.1.1.1
composite metric is 46670776/46251776

Answer: B

Explanation

First we must notice that all the 4 answers are parts of the “show ip eigrp topology” output. As you can see, there are 2 parameters in the form of [FD/AD] in each answer. For example answer A has [46152000/41640000], it means that the FD of that route is 46152000 while the AD is 41640000.

To become a feasible successor, a router must meet the feasibility condition:

“To qualify as a feasible successor, a router must have an AD less than the FD of the current successor route“

In four answer above, only answer B has an AD of 120256 and it is smaller than the FD of the current successor route (41152000) so it is the feasible successor -> B is correct.

Question 6

When running EIGRP what is required for RouterA to exchange routing updates with RouterC?

A. AS numbers must be changed to match on all the routers.
B. Loopback interface must be configured so a DR is elected.
C. The no auto-summary command is needed on Router A and Router C.
D. Router B needs to have two network statements, one for each connected network.

Answer: A

Explanation

We notice that 3 routers are using different AS numbers so they do not become neighbors and cannot exchange their routing updates. We need to choose only one AS number and use it on all 3 routers to make them exchange routing updates.

In this case we don’t need to use the “no auto-summary” command because network 10.0.0.0 is not separated by another major network.

Question 7

For the following routing protocols, which one uses bandwidth and delay as metrics by default?

A. EIGRP
B. RIP
C. BGP
D. OSPF

Answer: A

Question 8

A router is running three routing processes: RIP, OSPF, and EIGRP, each configured with default characteristics. Each process learns a route to the same remote network.
If there are no static routes to the destination and none of the routes were redistributed, which route will be placed in the IP routing table?

A. the route learned through EIGRP
B. the route learned through OSPF
C. the route learned through RIP
D. the route with the lowest metric
E. all three routes with the router load balancing

Answer: A

Question 9

To support the following IP addressing scheme, which routing protocols will be used? (Choose three)

Network 1 -192.168.10.0/26
Network 2 -192.168.10.64/27
Network 3- 192.168.10.96/27
Network 4-192.168.10.128/30
Network 5-192.168.10.132 /30

A. EIGRP
B. IGRP
C. OSPF
D. RIP version 2
E. RIP version 1
F. VTP
G. CDP

Answer: A C D

Explanation

All 5 networks above are subnetted -> all the classless routing protocols can be used as they do send the subnet mask in their updates so Variable Length Subnet Masks (VLSMs) are supported.

Question 10

Which routing protocols can be used within the enterprise network shown in the diagram? (Choose three)

A. RIP v1
B. RIPv2
C. IGRP
D. OSPF
E. BGP
F. EIGRP

Answer: B D F

Here you will find answers to OSPF Questions

Note: If you are not sure about OSPF, please read my OSPF tutorial

Question 1

After the network has converged, what type of messaging, if any, occurs between R3 and R4?

A. No messages are exchanged.

B. Hellos are sent every 10 seconds.

C. The full database from each router is sent every 30 seconds.

D. The routing table from each router is sent every 60 seconds.

Answer: B

Explanation

HELLO messages are used to maintain adjacent neighbors so even when the network is converged, hellos are still exchanged. On broadcast and point-to-point links, the default is 10 seconds, on NBMA the default is 30 seconds.

Although OSPF is a link-state protocol but the full database from each router is sent every 30 minutes (not seconds) -> C and D are not correct.

Question 2

R1 is configured with the default configuration of OSPF.

From the following list of IP addresses configured on R1, which address will the OSPF process select as the router ID?

A. 192.168.0.1

B. 172.16.1.1

C. 172.16.2.1

D. 172.16.2.225

Answer: A

Explanation

The Router ID (RID) is an IP address used to identify the router and is chosen using the following sequence:

+ The highest IP address assigned to a loopback (logical) interface.

+ If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen.

+ The router ID can be manually assigned

In this case, because a loopback interface is not configured so the highest active IP address 192.168.0.1 is chosen as the router ID.

Question 3

What information does a router running a link-state protocol use to build and maintain its topological database? (Choose two)

A. hello packets

B. SAP messages sent by other routers

C. LSAs from other routers

D. beacons received on point-to-point links

E. routing tables received from other link-state routers

F. TTL packets from designated routers

Answer: A C

Question 4

R1 is unable to establish an OSPF neighbor relationship with R3. What are possible reasons for this problem? (Choose two)

A. All of the routers need to be configured for backbone Area 1.

B. R1 and R2 are the DR and BDR, so OSPF will not establish neighbor adjacency with R3.

C. A static route has been configured from R1 to R3 and prevents the neighbor adjacency from being established.

D. The hello and dead interval timers are not set to the same values on R1 and R3.

E. EIGRP is also configured on these routers with a lower administrative distance.

F. R1 and R3 are configured in different areas.

Answer: D F

Explanation

To become OSPF neighbors, routers must meet these requirements: Hello interval, Dead interval and AREA number -> D and F are correct.

Question 5

ROUTER# show ip route

192.168.12.0/24 is variably subnetted, 9 subnets, 3 masks

C 192.168.12.64 /28 is directly connected, Loopback1

C 192.168.12.32 /28 is directly connected, Ethernet0

C 192.168.12.48 /28 is directly connected, Loopback0

O 192.168.12.236 /30 [110/128] via 192.168.12.233, 00:35:36, Serial0

C 192.168.12.232 /30 is directly connected, Serial0

O 192.168.12.245 /30 [110/782] via 192.168.12.233, 00:35:36, Serial0

O 192.168.12.240 /30 [110/128] via 192.168.12.233, 00:35:36, Serial0

O 192.168.12.253 /30 [110/782] via 192.168.12.233, 00:35:37, Serial0

O 192.168.12.249 /30 [110/782] via 192.168.12.233, 00:35:37, Serial0

O 192.168.12.240/30 [110/128] via 192.168.12.233, 00:35:36, Serial 0

To what does the 128 refer to in the router output above?

A. OSPF cost

B. OSPF priority

C. OSPF hop count

D. OSPF ID number

E. OSPF administrative distance

Answer: A

Explanation

The first parameter is the Administrative Distance of OSPF (110) while the second parameter is the cost of OSPF.

Question 6

Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two)

A. It is locally significant.

B. It is globally significant.

C. It is needed to identify a unique instance of an OSPF database.

D. It is an optional parameter required only if multiple OSPF processes are running on the router.

E. All routers in the same OSPF area must have the same process ID if they are to exchange routing information.

Answer: A C

Question 7

Open Shortest Path First (OSPF) is a routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working group of the Internet Engineering Task Force (IETF). What is the default administrative distance of the OSPF routing protocol?

A. 90

B. 100

C. 110

D. 20

E. 130

F. 170

Answer: C

Question 8

The internetwork infrastructure of company XYZ consists of a single OSPF area as shown in the graphic.

There is concern that a lack of router resources is impeding internetwork performance.

As part of examining the router resources the OSPF DRs need to be known.

All the router OSPF priorities are at the default and the router IDs are shown with each router.

Which routers are likely to have been elected as DR? (Choose two)

A. Corp-1

B. Corp-2

C. Corp-3

D. Corp4

E. Branch-1

F. Branch-2

Answer: D F

Explanation

There are 2 segments on the topology above which are separated by Corp-3 router. Each segment will have a DR so we have 2 DRs.

To select which router will become DR they will compare their router-IDs. The router with highest (best) router-ID will become DR. The router-ID is chosen in the order below:

+ The highest IP address assigned to a loopback (logical) interface.

+ If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen.

In this question, the IP addresses of loopback interfaces are not mentioned so we will consider IP addresses of all active router’s physical interfaces. Router Corp-4 (10.1.40.40) & Branch-2 (10.2.20.20) have highest “active” IP addresses so they will become DRs.

Question 9

Which address are OSPF hello packets addressed to on point-to-point networks?

A. 224.0.0.5

B. 172.16.0.1

C. 192.168.0.5

D. 223.0.0.1

E. 254.255.255.255

Answer: A

Question 10

Which statements describe the routing protocol OSPF? (Choose three)

A. It supports VLSM.

B. It is used to route between autonomous systems.

C. It confines network instability to one area of the network.

D. It increases routing overhead on the network.

E. It allows extensive control of routing updates.

F. It is simpler to configure than RIP v2.

Answer: A C E

Question 11

R1 is unable to establish an OSPF neighbor relationship with R3

What are possible reasons for this problem? (Choose two)

A. All of the routers need to be configured for backbone Area 1
B. R1 and R2 are the DR and BDR, so OSPF will not establish neighbor adjacency with R3
C. A static route has been configured from R1 to R3 and prevents the neighbor adjacency from being established.
D. The hello and dead interval timers are not set to the same values on R1 and R3
E. EIGRP is also configured on these routers with a lower administrative distance
F. R1 and R3 are configured in different areas

Answer: D F

Question 12

RouterD# show ip interface brief

Given the output for this command, if the router ID has not been manually set, what router ID will OSPF use for this router?

A. 10.1.1.2
B. 10.154.154.1
C. 172.16.5.1
D. 192.168.5.3

Answer: C

Here you will find answers to OSPF Questions – Part 2

Note: If you are not sure about OSPF, please read my OSPF tutorial

Question 1

OSPF routing uses the concept of areas. What are the characteristics of OSPF areas? (Choose three)

A. Each OSPF area requires a loopback interface to be configured.
B. Areas may be assigned any number from 0 to 65535.
C. Area 0 is called the backbone area.
D. Hierarchical OSPF networks do not require multiple areas.
E. Multiple OSPF areas must connect to area 0.
F. Single area OSPF networks must be configured in area 1.

Answer: C D E

Explanation

C and E are correct according to the theory of OSPF. For answer E, it is a bit unclear but we can understand “Hierarchical OSPF networks do not require multiple areas” is correct because there are networks that are small enough to use only area 0 for the whole network.

Question 2

Open Shortest Path First (OSPF) is a dynamic routing protocol for use in Internet Protocol (IP) networks.
If configuring all OSPF routers in a single area with the same priority value, what value does a router use for the OSPF router ID in the absence of a loopback interface?

A. the IP address of the first Fast Ethernet interface
B. the IP address of the console management interface
C. the highest IP address among its active interfaces
D. the lowest IP address among its active interfaces
E. the priority value until a loopback interface is configured

Answer: C

Question 3

R1 routing commands:
ip route 0.0.0.0 0.0.0.0 serial0/0
router ospf 1
network 172.16.100.0 0.0.0.3 area 0
network 172.16.100.64 0.0.0.63 area 0
network 172.16.100.128 0.0.0.31 area 0
default-information originate

Assuming that all router interfaces are operational and correctly configured, that OSPF has been correctly configured on router R2, how will the default route configured on R1 affect the operation of R2?

A. Any packet destined for a network that is not directly connected to router R1 will be dropped.
B. Any packet destined for a network that is not referenced in the routing table of router R2 will be directed to R1. R1 will then send that packet back to R2 and a routing loop will occur.
C. Any packet destined for a network that is not directly connected to router R2 will be dropped immediately.
D. Any packet destined for a network that is not directly connected to router R2 will be dropped immediately because of the lack of a gateway on R1.

Answer: B

Explanation

Please read the explanation of this question at http://www.9tut.com/ccna-ospf-questions (question 6)

Question 4

Border# debug ip ospf events
OSPF events debugging is on
Border#
*Nov 4 03:49:37477: OSPF: Rev hello from 10.10.3.3 area 0 from Serial0/3 192.168.255.18
*Nov 4 03:49:37.481: OSPF: End of hello processing
*Nov 4 03:49:37.641: OSPF: Rev hello from 10.10.1.1 area 0 from Serial0/1 192.168.255.22
“Nov 4 03:49:37.645: OSPF: Mismatched hello parameters from 192.168.255.22
*Nov 4 03:49:37.645: OSPF: Dead R 40 C 56, Hello R 10 C 14

What conclusion can be drawn from the output of the debug command presented in the exhibit?

A. The output represents normal OSPF operation.
B. A router is connected to interface Serial0/3 of the Border router.
The OSPF router ID of the connected router is the IP address of the connected interface.
C. The interfaces of two OSPF routers connected to the Border router are in the same subnet.
D. The OSPF router connected to interface Serial0/1 has NOT formed a neighbor relationship with the Border router.

Answer: D

Explanation

From the debug line “Mismatched hello parameters from 192.168.255.22” we learn that there is a mismatched parameter in the hello packet (Hello interval, Dead interval or AREA number).

Question 5

Which characteristics are representative of a link-state routing protocol? (Choose three)

A. provides common view of entire topology
B. exchanges routing tables with neighbors
C. calculates shortest path
D. utilizes event-triggered updates
E. utilizes frequent periodic updates

Answer: A C D

Question 6

When running OSPF, what would cause router A not to form an adjacency with router B?

A. The loopback addresses are on different subnets.
B. The values of the dead timers on the routers are different.
C. Route summarization is enabled on both routers.
D. The process identifier on router A is different than the process identifier on router

Answer: B

Question 7

What is the OSPF router ID in a DR/BDR election used for?

A. It is used with the OSPF priority values to determine which interface will be used to form a neighbor relationship with another OSPF router.
B. It is used with the OSPF priority values to determine which OSPF router will become the DR or BDR in a point-to-point network.
C. It is used with the OSPF priority values to determine which router will become the DR or BDR in a multiaccess network.
D. It is used to determine which interfaces will send Hello packets to neighboring OSPF routers.

Answer: C

Question 8

A network associate has configured OSPF with the command:
City(config-router)# network 192.168.12.64 0.0.0.63 area 0

After completing the configuration, the associate discovers that not all the interfaces are participating in OSPF.
Which three of the interfaces shown in the exhibit will participate in OSPF according to this configuration statement? (Choose three)

A. FastEthernet0/0
B. FastEthernet0/1
C. Serial0/0
D. Serial0/1.102
E. Serial0/1.103
F. Serial0/1.104

Answer: B C D

Explanation

The “network 192.168.12.64 0.0.0.63” equals to network 192.168.12.64/26. This network has:
+ Increment: 64 (/26= 1111 1111.1111 1111.1111 1111.1100 0000)
+ Network address: 192.168.12.64
+ Broadcast address: 192.168.12.127
Therefore all interface in the range of this network will join OSPF -> B C D are correct.

Question 9

To maintain connectivity with neighboring routers, routers running OSPF will send some type of packets. What is the type of packets?

A. OSP packets
B. hello packets
C. LSU packets
D. dead interval packets

Answer: B

Question 10

A network administrator is configuring the routers in the graphic for OSPF.
The OSPF process has been started and the networks have been configured for Area 0 as shown in the diagram.
The network administrator has several options for configuring RouterB to ensure that it will be preferred as the designated router (DR) for the 172.16.1.0/24 LAN segment.

What configuration tasks could be used to establish this preference? (Choose three)

A. Change the priority value of the Fa0/0 interface of RouterB to zero.
B. Configure the priority value of the Fa0/0 interface of RouterB to a higher value than any other interface on the Ethernet network.
C. Change the priority values of the Fa0/0 interfaces of RouterA and RouterC to zero.
D. Configure a loop back interface on RouterB with an IP address higher than any IP address on the other routers.
E. No further configuration is necessary.

Answer: B C D

Question 11

Open Shortest Path First (OSPF) is a dynamic routing protocol for use in Internet Protocol (IP) networks, while EIGRP is short for Enhanced Interior Gateway Routing Protocol. A large corporate which often integrates networks from newly acquired businesses has just decided to use OSPF to replace EIGRP as the corporate routing protocol.

Which two benefits will the corporation obtain by changing from EIGRP to OSPF? (Choose two)

A. the ability to automatically summarize networks
B. the ability to create a hierarchical design using areas
C. the ability to support multi-vendor routers
D. the ability to redistribute default and static routes
E. the ability to use VLSM

Answer: B C

Question 12

What are three characteristics of the OSPF routing protocol? (Choose three)

A. It converges quickly
B. OSPF is a classful routing protocol
C. It uses cost to determine the best route
D. It uses the DUAL algorithm to determine the best route
E. OSPF routers send the complete routing table to all directly attached routers
F. OSPF routers discover neighbors before exchanging routing information

Answer: A C F

Here you will find answers to ICND 2 – Operation Questions

Question 1

Refer to the exhibit. The following commands are executed on interface fa0/1 of 2950Switch.
2950Switch(config-if)#switchport port-security
2950Switch(config-if)#switchport port-security mac-address sticky
2950Switch(config-if)#switchport port-security maximum 1

The Ethernet frame that is shown arrives on interface fa0/1. What two functions will occur when this frame is received by 2950Switch? (Choose two)

A – The MAC address table will now have an additional entry of fa0/1 FFFF.FFFF.FFFF.
B – Only host A will be allowed to transmit frames on fa0/1.
C – This frame will be discarded when it is received by 2950Switch.
D – All frames arriving on 2950Switch with a destination of 0000.00aa.aaaa will be forwarded out fa0/1.
E – Hosts B and C may forward frames out fa0/1 but frames arriving from other switches will not be forwarded out fa0/1.
F – Only frames from source 0000.00bb.bbbb, the first learned MAC address of 2950Switch, will be forwarded out fa0/1.

Answer: B D

Explanation:

The first command 2950Switch(config-if)#switchport port-security is to enable the port-security in a switch port.

In the second command 2950Switch(config-if)#switchport port-security mac-address sticky, we need to know the full syntax of this command is switchport port-security mac-address sticky [MAC]. The STICKY keyword is used to make the MAC address appear in the running configuration and you can save it for later use. If you do not specify any MAC addresses after the STICKY keyword, the switch will dynamically learn the attached MAC Address and place it into your running-configuration. In this case, the switch will dynamically learn the MAC address 0000.00aa.aaaa of host A and add this MAC address to the running configuration.

In the last command 2950Switch(config-if)#switchport port-security maximum 1 you limited the number of secure MAC addresses to one and dynamically assigned it (because no MAC address is mentioned, the switch will get the MAC address of the attached MAC address to interface fa0/1), the workstation attached to that port is assured the full bandwidth of the port.Therefore only host A will be allowed to transmit frames on fa0/1 -> B is correct.

After you have set the maximum number of secure MAC addresses for interface fa0/1, the secure addresses are included in the “Secure MAC Address” table (this table is similar to the Mac Address Table but you can only view it with the show port-security address command). So in this question, although you don’t see the MAC address of host A listed in the MAC Address Table but frames with a destination of 0000.00aa.aaaa will be forwarded out of fa0/1 interface -> D is correct.

Question 2

A network administrator must configure 200 switch ports to accept traffic from only the currently attached host devices. What would be the most efficient way to configure MAC-level security on all these ports?

A – Visually verify the MAC addresses and then telnet to the switches to enter the switchport-port security mac-address command.
B – Have end users e-mail their MAC addresses. Telnet to the switch to enter the switchport-port security mac-address command.
C – Use the switchport port-security MAC address sticky command on all the switch ports that have end devices connected to them.
D – Use show mac-address-table to determine the addresses that are associated with each port and then enter the commands on each switch for MAC address port-security.

Answer: C

Explanation:

(Please read the explanation of question 1 to understand the use of the “switchport port-security MAC address sticky”)

A and C can be used, but instead of writing all the MAC addresses of the devices associated with each port, we can ask the switch to learn all the MAC addresses of the associated devices automatically by the “switchport port-security mac-address sticky” command which will save much work for the administrator.

Question 3

Refer to the exhibit. What can he concluded from the output of the debug command?

A – The output represents normal OSPF operation.
B – The interfaces of two OSPF routers connected to the Border router are in the same subnet.
C – The OSPF router connected to interface Serial0/1 has NOT formed a neighbor relationship with the Border router.
D – A router is connected to interface Serial0/3 of the Border router. The OSPF router ID of the connected router is the IP address of the connected interface.

Answer: C

Question 4

Refer to the exhibit. What does STATUS=ACTIVE refer to in the output of the show frame-relay pvc command?

A – The PVC is experiencing congestion.
B – The Frame Relay switch is correctly programmed with the DLCI and is operational.
C – The router is actively broadcasting to establish a link to the Frame Relay switch.
D – The router is connected to the local Frame Relay switch, but not to the far end device.

Answer: B

Question 5

Refer to the graphic. Users on the Holyoke router are unable to access the intranet server attached to interface E0 of the Chicopee router. Inspection of the routing table of the Holyoke router shows that an entry for the Chicopee E0 network is missing. Which command will configure the Holyoke router with a path to the intranet server network?

A – Holyoke(config)# ip host Chicopee 201.73.127.2
B – Holyoke(config)# ip host Chicopee 201.73.127.0 255.255.255.0
C – Holyoke(config)# ip network 202.18.38.0
D – Holyoke(config)# ip network 202.18.18.0 255.255.255.0
E – Holyoke(config)# ip route 202.18.18.0 255.255.255.0 201.73.127.2
F – Holyoke(config)# ip route 201.73.127.2 255.255.255.0 202.18.18.0

Answer: E

Question 6

Users have been complaining that their Frame Relay connection to the corporate site is very slow. The network administrator suspects that the link is overloaded. Based on the partial output of the Router#show frame relay pvc command shown in the graphic, which output value indicates to the local router that traffic sent to the corporate site is experiencing congestion?

A.DLCI = 100
B.last time PVC status changed 00:25:40
C.in BECN packets 192
D.in FECN packets 147
E.in DE packets 0

Answer: C

Explanation

If one of the intermediate Frame Relay switches encounters congestion, it will set the BECN (Backward Error Congestion Notification) bit on packets being returned to the sending device and the FECN (Forward Error Congestion Notification) bit on the packets being sent to the receiving device.

A FECN tells the receiving device that the path is congested so that the upper layer protocols should expect some delay. The BECN tells the transmitting device that the Frame Relay network is congested and that it should “back off” to allow better throughput.

The DE (Discard Eligibility) bit is used to identify less important traffic that can be dropped during periods of congestion. DCE devices will discard frames with the DE bit set before discarding those that do not.

Question 7

Refer to the exhibit. Which of these statements correctly describes the state of the switch once the boot process has been completed?

A. As FastEthernet0/12 will be the last to come up, it will be blocked by STP.
B. Remote access management of this switch will not be possible without configuration change.
C. More VLANs will need to be created for this switch.
D.The switch will need a different IOS code in order to support VLANs and STP.

Answer: B

Explanation

We don’t know the network topology so A is not correct.

A switch can operate without VLANs -> C is not correct.

This switch IOS supports VLAN because we can see VLAN 1 in the exhibit -> D is not correct.

In this case, VLAN 1 has been shutdown so we can’t remote access to this switch -> B is correct.

Here you will find answers to ICND 2 – Hotspot Questions

Question:

Refer to the topology. Using the information shown, answer the five questions shown on the Questions tab

Question 1:

If most of the communication is between hosts and the servers, which switch is best as the root switch for VLAN 20?

A – Sw-A
B – Sw-B
C – Sw-C
D – Sw-D
E – Sw-E

Answer: E

Explanation:

Server 3 and Server 4 belong to VLAN 20 and are connected to Switch-E. If the question asks which switch is best for the whole network then the answer should be Switch-B because it is the most centralized switch on the network.

Question 2:

If Sw-E is the root for all VLANs, which of the following is a valid path from host A to Server 1?

A – Sw-A, Sw-D
B – Sw-A, Sw-E, Sw-D
C – Sw-A, Sw-B, Sw-C, Sw-D
D – Sw-A, Sw-E, Sw-C, Sw-D
E – Sw-A, Sw-E, Sw-A, Svv-D

Answer: D

Explanation:

All the traffic must go through root switch so the shortest path should be Sw-A -> Sw-E -> Sw-C -> Sw-D (notice that traffic can not go through Sw-A -> Sw-E and back to Sw-A again)

Question 3:

What technology helps prevent frames from looping continuously through this switched network?

A – ARP
B – VTP
C – STP
D – EIGRP
E – CSMA/CD

Answer: C

Question 4:

What, if anything, is required for communication to occur between the host C and Server 3?

A – DHCP
B – a router
C – nothing is required
D – trunk link between Sw-B and Sw-E

Answer: B

Explanation:

Since host C (VLAN 10) and Server 3 (VLAN 20) belong to different VLANs so we need a Layer 3 device (like a router) for inter-VLAN communication.

Question 5:

What type of link is needed between Sw-A and Sw-B so host C and host D can communicate through Sw-A to the servers?

A – trunk
B – access
C – multi-access
D – straight-through

Answer: A

Explanation:

Communication between different VLANs requires a trunk link to forward traffic normally.

Question:

Drag the options on the left under the type of switch port that they describe on the right.

Answer:

Here you will find answers to ICND 2 – Subnetting Questions

Note: If you are not sure about subnetting, please read my Subnetting tutorial.

Question 1:

Refer to the exhibit. The lakeside Company has the internetwork in the exhibit. The Administrator would like to reduce the size of the routing table to the Central Router. Which partial routing table entry in the Central router represents a route summary that represents the LANS in Phoenix but no additional subnets?

A – 10.0.0.0 /22 is subnetted, 1 subnet
D 10.0.0.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

B – 10.0.0.0 /28 is subnetted, 1 subnet
D 10.2.0.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

C – 10.0.0.0 /30 is subnetted, 1 subnet
D 10.2.2.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

D – 10.0.0.0 /22 is subnetted, 1 subnet
D 10.4.0.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

E – 10.0.0.0 /28 is subnetted, 1 subnet
D 10.4.4.0 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

F – 10.0.0.0 /30 is subnetted, 1 subnet
D 10.4.4.4 [90/20514560] via 10.2.0.2 6w0d, serial 0/1

Answer: D

Question 2:

Refer to the exhibit. HostA cannot ping HostB. Assuming routing is properly configured. what could be the cause of this problem?

A – HostA is not on the same subnet as its default gateway.
B – The address of SwitchA is a subnet address.
C – The Fa0/0 interface on RouterA is on a subnet that can’t be used.
D – The serial interfaces of the routers are not on the same subnet.
E – The Fa0/0 interface on Routers is using a broadcast address.

Answer: D

Question 3:

Refer to the exhibit. The routers are running RIPv2. Which addressing scheme would satisfy the needs of this network yet waste fewest addresses?

A – Network 1: 1 92.168.10.0/26
Network 2: 1 92.168.10.64/26
Network 3: 1 92.168.10.128/26
Serial link 1: 192.168.20.0/24
Serial link 2: 192.168.30.0/24

B – Network 1: 1 92.168.10.0/26
Network 2: 1 92.168.10.64/28
Network 3: 1 92.168.10.80/29
Serial link 1: 192.168.10.88/30
Serial link 2: 192.168.10.96/30

C – Network 1: 1 92.168.10.0/26
Network 2: 1 92.168.10.64/27
Network 3: 1 92.168.10.96/28
Serial link 1: 192.168.10.112/30
Serial link 2: 192.168.10.116/30

D – Network 1: 1 92.168.10.0/27
Network 2: 1 92.168.10.64/28
Network 3: 1 92.168.10.96/29
Serial link 1: 192.168.10.112/30
Serial link 2: 192.168.10.116/30

Answer: C

Here you will find answers to ICND 2 – Drag And Drop Questions

Question 1

Two offices are displayed below

You work as a network technician at 9tut.net. Study the exhibit carefully. The company has a main office in Los Angeles and a satellite office in Boston. The offices are connected through two Cisco routers. The Boston satellite office is connected through the R2 router s0 interface to the Los Angeles office R1 router s1 interface. R1 has two local area networks. Boston users receive Internet access through the R1 router. Drag the boxes on the top to complete the goal on the left.

Answer:

1) Prevent all users from outside the enterprise network from accessing the server: permit ip 192.168.35.0 0.0 0.255 host 192.168.35.66
2) Block a user from R1 e0 network from accessing the server: deny ip 192.168.35.55 0.0.0.0 host 192.168.35.66
3) Block only the users attached to the e0 interface of the R2 router from accessing the server: deny ip 192.168.35.16 0.0.0.15 host 192.168.35.66

Question 2

You are configuring the 9tut.net office. In particular the host C, with the IP address 192.168.125.34/27, needs to be configured so that it cannot access hosts outside its own subnet. You decide to use the following command:
access-list 100 deny protocol address mask any

You are required to fill in the protocol, address, and mask in this command using the choices below:

Answer:

1) protocol: ip
2) address: 192.168.125.34
3) mask: 0.0.0.0

Explanation

The syntax of extended access-list:

access-list 100-199 {permit|deny} {ip|tcp|udp|icmp} source source-mask [lt|gt|eq|neq] [source-port] destination dest-mask [lt|gt|eq|neq] [dest-port]

By telling the router to drop traffic originated from host C (source), we can guarantee that host C can just communicate with hosts inside its own subnet (because this kind of traffic does not need to pass the router and will not be prevented).

Question 3

Exhibit:

Study the exhibit carefully. You need to match output lines in the exhibit with the proper OSI layer. One line will not be used.

Answer:

Data Link Layer:

+ Encapsulation PPP
+ Line protocol is up

Physical Layer:

+ Serial 1/0 is up
+ Hardware is CD2430 in sync mode

Question 4

You work as a network administrator for your corporation, your boss is interested in switch ports. Match the options to the appropriate switch ports

Answer:

Access Port:

+ carries traffic for a single VLAN
+ uses a straight-through cable to connect a device
+ connects an end-user workstation to a switch

Trunk Port:

+ carries traffic for a multiple VLAN
+ Facilitates interVLAN communications when connected to a Layer 3 device
+ uses 802.1q to identify traffic from different VLANs

Question 5

Below is the configuration of the R1 router:

R1(config)# ip route 0.0.0.0 0.0.0.0 192.168.1.1
R1(config)# ip route 10.1.0.0 255.255.255.0 192.168.2.2
R1(config)# ip route 10.1.0.0 255.255.0.0 192.168.3.3

Drag each destination IP address on the top to its correct next hop address at the bottom.

Answer:

Next hop 192.168.1.1:
+ 10.2.1.3
+ 10.6.8.4

Next hop 192.168.2.2:
+ 10.1.0.14
+ 10.1.0.123

Next hop 192.168.3.3:
+ 10.1.1.10
+ 10.1.4.6

Here you will find answers to ICND 2 – Drag and Drop Questions Part 2

Question 1

Match the categories with the appropriate router output lines.

Answer:

1) Port operational: Serial0/1 is up, line protocol is up
2) Layer 2 problem: Serial0/1 is up, line protocol is down
3) Layer 1 problem: Serial0/1 is down, line protocol is down
4) Port disabled: Serial0/1 is administratively down, line protocol is down

Explanation:

A simple way to find out which layer is having problem is to remember this rule: “the first statement is for Layer 1, the last statement is for Layer 2 and if Layer 1 is down then surely Layer 2 will be down too”, so you have to check Layer 1 before checking Layer 2. For example, from the output “Serial0/1 is up, line protocol is down” we know that it is a layer 2 problem because the first statement (Serial0/1 is up) is good while the last statement (line protocol is down) is bad. For the statement “Serial0/1 is down, line protocol is down”, both layers are down so the problem belongs to Layer 1.

There is only one special case with the statement “…. is administratively down, line protocol is down”. In this case, we know that the port is currently disabled and shut down by the administrators.

Question 2

The above provides some descriptions, while the below provides some routing protocols. Drag the above items to the proper locations.

Answer:

EIGRP:

+ has a default administrative distance of 90
+ is vendor-specific

OSPF:

+ uses cost as its metric
+ elects a DR on each multiaccess network

Question 3

Drag the term on the left to its definition on the right (not all options are used)

Answer:

+ poison reverse: A router learns from its neighbor that a route is down and the router sends an update back to the neighbor with an infinite metric to that route
+ LSA: The packets flooded when a topology change occurs, causing network routers to update their topological databases and recalculate routes
+ split horizon: This prevents sending information about a routeback out the same interface that originally learned about the route
+ holddown timer: For a given period, this causes the router to ignore any updates with poorer metrics to a lost network

Question 4

Drag the appropriate description to the correct locations

Answer:

RIP Version 1

+ sends frequent updates
+ less complex configuration
+ susceptible to routing loops
+ exchanges full routing table in updates

OSPF
+ faster convergence
+ uses only event-triggered updates
+ same topology information on all routers
+ uses more RAM and processor power

Question 5

Answer:

+ holddown timer: prevents a router from improperly reinstating a route from a regular routing update
+ split horizon: prevents information about a route from being sent in the direction from which the route was learned
+ defining a maximum: prevents invalid updates from looping the internetwork indefinitely
+ route poisoning: causes a routing protocol to advertise an infinite metric for a failed route
+ triggered update: decreases convergence time by immediately sending route information in response to a topology change

Here you will find answers to Drag and Drop Questions – Part 3

Question 1

Drag item on left to match item on right

Answer:
+ Point to Point Advantage: Quality
+ Point to Point Disadvantage: Limited Flexibility
+ Circuit Switched Advantage: Cost
+ Circuit Switched Disadvantage: Low speed
+ Packet Switch Advantage: Efficient
+ Packet Switch Disadvantage: More Complex

Question 2

Place the Spanning-Tree Protocol port state on its functions (not all options on the left are used)

Answer:

+ Populating the MAC address table but not forwarding data frames: LEARNING
+ Sending and receiving data frames: FORWARDING
+ Preparing to forward data frames without populating the MAC address table: LISTENING
+ Preventing the use of looped paths: BLOCKING

Question 3

As a CCNA candidate, you need to know EIGRP very well.
Which tables of EIGRP route information are held in RAM and maintained through the use of hello and update packets?

Please choose two appropriate tables and drag the items to the proper locations.

Answer:

Neighbor Table
Topology Table

Here you will find answers to Miscellaneous Questions

Question 1

For what two purposes does the Ethernet protocol use physical addresses? (Choose two)

A. to uniquely identify devices at Layer 2
B. to allow communication with devices on a different network
C. to differentiate a Layer 2 frame from a Layer 3 packet
D. to establish a priority system to determine which device gets to transmit first
E. to allow communication between different devices on the same network
F. to allow detection of a remote device when its physical address is unknown

Answer: A E

Question 2

In the communication between host 1 and host 2 over the point-to-point WAN, which protocol or technology is represented by dashed line A?

A. IP
B. T1
C. ppp
D. IEEE 802.3

Answer: A

Question 3

What three pieces of information can be used in an extended access list to filter traffic? (Choose three)

A. protocol
B. VLAN number
C. TCP or UDP port numbers
D. source switch port number
E. source IP address and destination IP address
F. source MAC address and destination MAC address

Answer: A C E

Question 4

For security reasons, the network administrator needs to prevent pings into the corporate networks from hosts outside the internetwork. Which protocol should be blocked with access control lists?

A. IP
B. ICMP
C. TCP
D. UDP

Answer: B

Question 5

An administrator attempts a traceroute but receives a “Destination Unreachable” message. Which protocol is responsible for that message?

A. RARP
B. RUDP
C. ICMP
D. SNMP

Answer: C

Question 6

What are two characteristics of Frame Relay point-to-point subinterfaces? (Choose two)

A. They create split-horizon issues.
B. They require a unique subnet within a routing domain.
C. They emulate leased lines.
D. They are ideal for full-mesh topologies.
E. They require the use of NBMA options when using OSPF.

Answer: B C

Question 7

From EIGRP, OSPF, and a static route, a router learns about a remote network.
Assuming that default administrative distance is used by all routing protocols, to forward data to the remote network, which route will the router use?

A. The router will use the OSPF route.
B. The router will use the EIGRP route.
C. The router will use the static route.
D. The router will load balance and use all three routes.

Answer: C

Question 8

To connect the autonomous systems, which routing protocol should be used?

A. RIP
B. OSPF
C. BGP
D. EIGRP

Answer: C

This is a testlet. The testlet consists of 4 questions that relate to the scenario below:

Directions: Refer to the exhibit. This testlet consists of four questions that address steps in the process of data communication between host F and the server named WWW” on another LAN. You are free to move back and forth between the questions to review your answers.

Question 1:

In order to begin communicating with the server, host F sends out an ARP request. How will the devices exhibited in the topology respond to this request?

A – Switch West _1 will reply with the MAC address of the server.
B – Hosts D and E will respond that the destination is not on the local LAN.
C – Router SFX will forward the ARP request to the ILM router .
D – Switch West _1 will block the request since the server is not on the LAN.
E – The ILM router will respond with the IP address of the WWW server.
F – Router SFX will respond with the MAC address of its Fa0/0 interface.

Answer: F

Explanation:

Because the server WWW is on another LAN of host F, host F knows that it has to send its packets to the default gateway. Therefore, for the first time, it will send out an ARP broadcast message asking for the MAC address of router SFX. Router SFX receives this message and replies with the MAC address of Fa0/0 interface. Later, when host F wants to send packets to WWW server, it will include the IP address of WWW server and the MAC address of Fa0/0 interface of SFX router in the “destination IP address” and “destination MAC address” fields, respectively.

Question 2:

The ARP reply has been received by host F, which needs to build the packet. What information will be placed in the header of the packet that leaves host F if host F is to communicate with the WWW server? (Choose two)

A – The destination address will be the IP address of interface Fa0/0 of the ILM router .
B – The destination address will be the IP address of the WWW server.
C – The destination address will be the IP address of interface Fa0/0 of router SFX.
D – The source address will be the IP address of host F.
E – The source address will be the IP address of interface Fa0/0 of router SFX.
F – The destination address will be the IP address of interface Fa0/0 of router SFX.

Answer: B D

Explanation:

After receiving ARP reply from SFX router, host F will place these fields in the header of the packets:

Source addresses: the IP address of host F and the MAC address of host F
Destination addresses: the IP address of WWW server and the MAC address of SFX router

Question 3:

The frame has been received by the ILM router and is to be delivered on the local LAN. Which two statements describe the addressing of the Ethernet frame that has been created by the ILM router ? (Choose two)

A – The destination address will the be the MAC address of the switch A port attached to the Fa0/0 interface of the ILM router .
B – The destination address will be the MAC address of the WWW server.
C – The destination address will be the MAC address of the A switch port attached to the WWW server.
D – The source address will be the MAC address of host F.
E – The source address will be the MAC address of interface Fa0/0 of the ILM router.

Answer: B E

Question 4:

Host F is displaying two World Wide Web documents from the WWW server in two browser windows at the same time. How did the data find its way to the correct browser windows?

A – The IP source addresses of the packets will be used to direct the data to the correct browser window.
B – The browsers track the data by the URL.
C – TCP port numbers are used to direct the data to the correct application window.
D – The OSI application layer tracks the conversations and directs them to the correct browser.

Answer: C

Explanation:

TCP and UDP protocol port numbers are designed to distinguish multiple applications running on a single device from one another. In the TCP and UDP header, there are “Source Port” and “Destination Port” fields which are used to indicate the message sending process and receiving process identities defined. The combination of the IP address and the port number is called “socket”.

Other lab-sims in the ICND 1 Exam:

ICND 1 – Show Configuration Sim

ICND 1 – Implementation SIM

ICND 1 – RIPv2 SIM

ICND 1 – Implementation Sim 2

Frame Relay Sim – Hotspot (on 9tut.com)

Other lab-sims might appear in the real ICND 1 exam, read and understand them if you have enough time!

Please share with us your experience after taking the exam ICND2, your materials, the way you learned, your recommendations…

Read more…

Here you will find answers to hotspot questions in ICND 1 exam

Refer to the topology. Using the information shown, answer the five questions shown on the Questions tab.

Question 1:

On which router should a default route be configured?

A – on the ISP router
B – on R1
C – on R2
D – on R3
E – on R4

Answer: B

Question 2:

With all links operational and all routers converged, which of the following describes the messaging between routers?

A – Hellos are sent every five seconds.
B – Multicasts are sent every 60 seconds.
C – Broadcasts are sent every 30 seconds.
D – No messaging unless the topology changes.

Answer: C

Question 3:

Which of the following describes the route update process if the interface from R4 connected to LAN 4 goes down?

A – No updates occur
B – R4 tells both R1 and R3 the network not accessible. Both R3 and R1 update R2.
C – R4 tells only R1 the network is not accessible. R1 updates R2 and R2 updates R3.
D – R4 tells only R3 the network is not accessible. R3 updates R2 and R2 updates R1.

Answer: B

Question 4:

Why would RIP be used rather than static routes on R1, R2, R3, and R4?

A – RIP creates more accurate than static routes.
B – RIP uses less network resources than do static routes.
C – RIP is supported by more different vendors equipment than static routes.
D – RIP requires less configuration to automatically adjust when links go down than static routes.

Answer: D

Question 5:

On which router should a static route be configured?

A – on the ISP router
B – on R1
C – on R2
D – on R3
E – on R4

Answer: A

Here you will find answers to operation questions in ICND 1 exam

Question 1:

Refer to the exhibit. The junior network support staff provided the diagram as a recommended configuration for the first phase of a four-phase network expansion project. The entire network expansion will have over 1000 users on 14 network segments and has been allocated this IP address space:

192.168.1.1 through 192.168.5.255
192.168.100.1 through 198.168.100.255

What are three problems with this design? (Choose three)

A – The AREA 1 IP address space is inadequate for the number of users.
B – The AREA 3 IP address space is inadequate for the number of users.
C – AREA 2 could use a mask of /25 to conserve IP address space.
D – The network address space that is provided requires a single network-wide mask.
E – The router-to-router connection is wasting address space.
F – The broadcast domain in AREA 1 is too large for IP to function.

Answer: A C E

Question 2:

Refer to the exhibit. A technician is testing connection problems in the internetwork. What is the problem indicated by the output from HostA?

A – The routing on Router2 is not functioning properly.
B – An access list is applied to an interface of Router3.
C – The Fa0/24 interface of Switch1 is down.
D – The gateway address of HostA is incorrect or not configured.

Answer: D

Explanation:

When trying to ping the IP 192.168.3.254,you received the replies from that IP. It means that you can reach the Fa0/0 interface of Router1. But notice that the IP of host A (192.168.3.1/24) and the IP of the Fa0/0 interface of Router 1 (192.168.3.254/24) are on the same network. So you don’t need a gateway address configured on HostA. Therefore you can’t conclude the gateway address of HostA was configured correctly.

Lately, you tried to use the tracert command to reach another network (192.168.4.7). In this case, a gateway address was required for reaching the network of hostB. But the result told that “Destination host unreachable” – means that Host A can not find a route to Host B -> The gateway address of Host A was incorrect (something other than 192.168.3.254) or not configured is a possibility.

A and B are incorrect because if there is a mis-configuration on Router 2 or Router 3 (while Router 1 is configurated correctly), you will see at least one successful line when using tracert command likes the bold line below:

PC>tracert 192.168.4.7

Tracing route to 192.168.4.7 over a maximum of 30 hops:

1 62 ms 62 ms 46 ms 192.168.3.254
2 * * * Request timed out.

C is incorrect because we can ping Router 1 -> port Fa0/24 on Switch 1 was turned on and running correctly.

Question 3:

Refer to the exhibit. The internetwork is using subnets of the address 192.168.1.0 with a subset mask of 255.255.255.224. The routing protocol in use is RIP version 1. Which address could be assigned to the FastEthernet interface on RouterA?

A – 192.168.1.31
B – 192.168.1.64
C – 192.168.1.127
D – 192.168.1.190
E – 192.168.1.192

Answer: D

Explanation:

255.255.255.224 = 1111 1111.1111 1111.1111 1111.1110 0000 (binary form)

Increment: 32

First subnetwork: 192.168.1.0 -> 192.168.1.31 (A is incorrect because 192.168.1.31 is a broadcast address)
Second subnetwork: 192.168.1.32 -> 192.168.1.63
Third subnetwork: 192.168.1.64 -> 192.168.1.95 (B is incorrect because 192.168.1.64 is a network address)
Fourth subnetwork: 192.168.1.96 -> 192.168.1.127 (C is incorrect because 192.168.1.127 is a broadcast address)
Fifth subnetwork: 192.168.1.128 -> 192.168.1.159
Sixth subnetwork: 192.168.1.160 -> 192.168.1.191 (D is correct because 192.168.1.190 is the last assignable host address of this subnetwork)
Seventh subnetwork: 192.168.1.192 -> 192.168.1.224 (E is incorrect because 192.168.1.192 is a network address)

Question 4:

Refer to the exhibit. For security reasons, information about RTA, including platform and IP addresses, should not be accessible from the Internet. This information should, however, be accessible to devices on the internal networks of RTA. Which command or series of commands will accomplish these objectives?

A – RTA(config)#no cdp run
B – RTA(config)#no cdp enable
C – RTA(config)#interface s0/0
RTA(config-if)#no cdp run
D – RTA(config)#interface s0/0
RTA(config-if)#no cdp enable

Answer: D

Question 5:

Refer to the exhibit, PC1 pings PC2. What three things will CORE router do with the data that is received from PC1? (Choose three)

A – The data frames will be forwarded out interface FastEthernet0/1 of CORE router.
B – The data frames will be forwarded out interface FastEthernet1/0 of CORE router.
C – CORE router will replace the destination IP address of the packets with the IP address of PC2.
D – CORE router will place the MAC address of PC2 in the destination MAC address of the frames.
E – CORE router will put the IP address of the forwarding FastEthernet interface in the place of the source IP address in the packets.
F – CORE router will put the MAC address of the forwarding FastEthernet interface in the place of the source MAC address.

Answer: B D F

Here you will find answers to subnetting questions in ICND 1 exam

Note: If you are not sure about subnetting, please read my Subnetting tutorial.

Question 1

Refer to the exhibit. The goal of this network design is to provide the most efficient use of IP address space in a network expansion. Each circle defines a network segment and the number of users required on that segment. An IP subnetwork number and default gateway address are shown for each segment.

What are three problems with the network design as shown? (Choose three)

A – Interface fa0/3 has an IP address that overlaps with network 10.1.3.0/30.
B – Interface fa0/1 has an invalid IP address for the subnet on which it resides.
C – Interface fa0/2 has an invalid IP address for the subnet on which it resides.
D – Network 10.1.2.0/25 requires more user address space.
E – Network 10.1.3.128/25 requires more user address space.
F – The IP subnet 10.1.1.0/30 is invalid for a segment with a single server.

Answer: A B D

Explanation

Answer A should be “Interface fa0/3 has an invalid IP address for the subnet on which it resides” to be the correct answer. But there is no better solution (answers C E F are obviously incorrect) so we must choose answer A.

Question 2:

If an ethernet port on a router was assigned an IP address of 172.16.112.1/20, what is the maximum number of hosts allowed on this subnet?

A – 1024
B – 2046
C – 4094
D – 4096
E – 8190

Answer: C

Question 3:

Refer to the exhibit. The internetwork is using subnets of the address 192.168.1.0 with a subnet mask of 255.255.255.224. The routing protocol in use is RIP version 2. Which address could be assigned to the FastEthernet interface on RouterA?

A – 192.168.1.31
B – 192.168.1.64
C – 192.168.1.127
D – 192.168.1.190
E – 192.168.1.192

Answer: D

Question 4:

Refer to the exhibit. HostA cannot ping HostB. Assuming routing is properly configured, what could be the cause of this problem?

A – HostA is not on the same subnet as its default gateway.
B – The address of SwitchA is a subnet address.
C – The Fa0/0 interface on RouterA is on a subnet that can’t be used.
D – The serial interfaces of the routers are not on the same subnet.
E – The Fa0/0 interface on RouterB is using a broadcast address.

Answer: D

Here you will find answers to drag and drop questions in ICND 1 exam

Question 1:

Drag the appropriate command on the left to the configuration task it accomplishes (not all options are used)

Answer:

1) service password-encryption
2) line console 0
password friendS0nly
3) enable secret noWay1n4u
4) line vty 0 4
password 2hard2Guess
5) enable password uwi11NeverNo

Question 2:

Construct the command sequence to configure an IP address on a serial interface (not all options are used)

Answer:

1) Hub# configure terminal
2) Hub(config)# interface s0/0
3) Hub(config-if)# ip address 10.8.5.255 255.255.252.0
4) Hub(config-if)# no shutdown
5) Hub(config-if)# description T1 to WAN

Explanation:

One thing interesting in the answers is that the command ip address “10.8.5.255 255.255.252.0” (answer 3) is correct because 10.8.5.255 255.255.255.0 is not a broadcast address. Let’s analyze this case a bit closer:

Increment: 4 for the third octet (255.255.252.0 = 1111 1111.1111 1111.1111 1100.0000 0000)
First subnetwork range: 10.8.0.0 to 10.8.3.255
Second subnet range: 10.8.4.0 to 10.8.7.255
…

Therefore 10.8.3.255 and 10.8.7.255 are the broadcast addresses but not 10.8.5.255. So we can assign this address to s0/0 interface.

( Notice that the command Hub(config)# ip address 172.16.20.21 255.255.255.0 is only correct only if it is in interface mode, which is Hub(config-if)# )

Question 3:

Drag the commands on the left to the appropriate functions on the right (Not all options are used)

Answer:

1) ipconfig /all
2) tracert
3) telnet
4) ping 127.0.0.1
5) arp -a

Here you will find answers to ICND 1 – Drag and Drop Questions Part 2

Question 1

As a CCNA candidate, you should master the functions of various commands. Look at the following items, some commands are listed on the left. The related roles are listed on the right in a wrong sequence. Please match them together. (Not all options are used)

Answer:

1) Router#copy tftp flash: replace the IOS image
2) Router#copy flash tftp: backup the current IOS image
3) Router#copy running-config tftp: make a backup copy of configuration in RAM
4) Router#copy running-config startup-config: make the configuration in RAM the configuration the router will use on startup
5) Router#copy tftp running-config: merge a backup configuration with the configuration in RAM

Explanation

First please notice that by saying “replace” we often mean changes to NVRAM and TFTP while saying “merge” or “add” we mean changes to RAM. Next we should review the syntax of “copy” command:

Syntax: copy <source> <base config filename> <destination> <destination filename.txt>

1) By default, the flash memory in a router is used to store the Cisco IOS image so the requirement “replace the IOS image” means that moving file somewhere to the flash memory. In the left columns we only have one choice which has the flash as the destination ->copy tftp flash.

2) Same explanation as above, when saying “backup the current IOS image” the flash takes the role as the source ->copy flash tftp. And “backup” means we should copy it to somewhere like tftp server, CDROM…

3) The running-config is stored in the RAM so “make a backup copy of configuration in RAM” means copy running configuration from RAM so backup server (tftp) -> copy running-config tftp

4) “copy running-config startup-config” is a very common command so no more explanation needed.

5) After solving 4 boxes above, we only have two choices left: “copy tftp running-config” & “copy flash running-config”. The bottom-right box says “merge a backup configuration” so it should be the tftp server and the command here is copy tftp running-config.

Here you will find answers to Wireless Questions – Part 1

If you are not sure about Wireless, please read my Wireless tutorial and Basic Wireless Terminologies

Question 1

Which wireless LAN design ensures that a mobile wireless user will not lose connectivity when moving from one access point to another on the WLAN?

A. Utilizing MAC address filtering to allow the client MAC address to authenticate with the surrounding APs
B. Using adapters and access points manufactured by the same company
C. Overlapping the wireless cell coverage by at least 10%
D. Configuring all access points to use the same channel

Answer: C

Explanation

By using more than one Access Point (AP) we can create overlapping cells to allow roaming in a larger area. But we have to ensure that two APs must have at least 10% coverage overlap and they use non-overlapping channels.

Question 2

You need to troubleshoot an interference issue with the wireless LAN. Which two devices can interfere with the operation of this network because they operate on similar frequencies? (Choose two)

A. Microwave oven
B. AM radio
C. Toaster
D. Copier
E. Cordless phone
F. IP phone
G. Ipod

Answer: A E

Explanation

Microwave oven and cordless phone radiate energy in the 2.4 GHz unlicensed band so they can interfere with some WLAN standards. As the result of that, you can’t hear clearly on the phone or can’t surf web.

Question 3

Which of the following data network would you implement if you wanted a wireless network that had a relatively high data rate, but was limited to very short distances?

A. Broadband personal comm. Service (PCS)
B. Broadband circuit
C. Infrared
D. Spread spectrum
E. Cable

Answer: C

Explanation

Infrared typically requires a line-of-sight (your TV remote control, for example) which means that it is limited to very short distances. I am not sure if it is considered “relative high data rate” but infrared can transfer up to 4Mpbs.

Question 4

You need to add a wireless access point to a new office. Which additional configuration step is necessary in order to connect to an access point that has SSID broadcasting disabled?

A. Configure open authentication on the AP and the client
B. Set the SSID value in the client software to public
C. Set the SSID value on the client to the SSID configured on the AP
D. Configure MAC address filtering to permit the client to connect to the AP

Answer: C

Explanation

Service Set Identifier (SSID) is the term to identify a WLAN. In most cases SSID is broadcast by the AP, the user only needs to select that SSID and provides a correct password to access it. But in some cases for security reason, the SSID can be disabled. Users can only access to that network if they type both SSID and password correctly.

Question 5

You need to secure a new access point on the a wireless network. Which two practices help secure the configuration utilities on wireless access points from unauthorized access? (Choose two)

A. Changing the default SSID value
B. Configuring traffic filtering
C. Changing the mixed mode setting to single mode
D. Configuring a new administrator password
E. Assigning a private IP address to the AP

Answer: A D

Explanation

To improve security, you should change the default SSID value on your AP. For example, Linksys routers (which are produced by Cisco) typically have an SSID of “linksys” -> A is correct.

In an AP we can configure traffic filtering but it is mainly used for filtering which services clients can use, IP ranges, ports, websites, time access… It has no effect on securing your AP -> B is not correct.

“Mixed mode” here means we can configure AP to allow clients to use different standard like 802.11b, g or n. But setting it to single mode doesn’t have any security protection on it -> C is not correct.

We should also change the administrator password because everyone can access to the admin page of an AP by open a web browser and type the IP address of that AP (for example: http://192.168.1.1). Typically, Linksys Wireless routers have a default username/password of “admin/admin” or “admin/[blank]” which are easily guessed or found out -> D is correct.

We can access the AP by using a private IP address (in the same private network of the AP – 192.168.1.1, for example) -> E is not correct.

Question 6

You need to determine the proper security settings on a new WLAN-capable office. Which encryption type would WPA2 use in this office?

A. PSK
B. AES-CCMP
C. PPK via IV
D. TKIP/MIC
E. None of the other alternatives apply

Answer: B

Explanation

Advanced Encryption Standard (AES) is the cipher system used by RSN. It is the equivalent of the RC4 algorithm used by WPA. However the encryption mechanism is much more complex and does not suffer from the problems associated with WEP. AES is a block cipher, operating on blocks of data 128bits long.

CCMP is the security protocol used by AES. It is the equivalent of TKIP in WPA. CCMP computes a Message Integrity Check (MIC) using the well known, and proven, Cipher Block Chaining Message Authentication Code (CBC-MAC) method. Changing even one bit in a message produces a totally different result.

The AES-CCMP encryption algorithm used in the 802.11i (WPA2) security protocol. It uses the AES block cipher, but restricts the key length to 128 bits. AES-CCMP incorporates two sophisticated cryptographic techniques (counter mode and CBC-MAC) and adapts them to Ethernet frames to provide a robust security protocol between the mobile client and the access point.

Question 7

What is one reason why WPA encryption is preferred over WEP in this network?

A. The WPA key values remain the same until the client configuration is changed.
B. The values of WPA keys can change dynamically while the system is used.
C. The access point and the client are manually configured with different WPA key values.
D. A WPA key is longer and requires more special characters than the WEP key.
E. None of the other alternatives apply

Answer: B

Explanation

Wireless Encryption Protocol (WEP) uses RC4 encryption and a static 64-bit key so it can be easily broken as only 40-bits are encrypted and 24 bits are clear-text IV(Initialization Vector). It was later upgraded to 128-bit, but the IV was still clear text meaning it took slightly longer (minutes) to break-in.

WPA was introduced in 2003 as a replacement for WEP. WPA uses Temporal Key Integrity Protocol (TKIP) to automatically change the keys. TKIP still uses RC4; it just improves how it’s done

Question 8

In an effort to increase security within the wireless network, WPA is being utilized. Which two statements shown below best describe the wireless security standard that is defined by WPA? (Choose two)

A. It requires use of an open authentication method
B. It specifies use of a static encryption key that must be changed frequently to enhance security
C. It includes authentication by PSK
D. It specifies the use of dynamic encryption keys that change each time a client establishes a connection
E. It requires that all access points and wireless devices use the same encryption key
F. WPA works only with Cisc0 access points

Answer: C D

Question 9

You need to configure a new wireless access point for your network. What are three basic parameters to configure an AP? (Choose three)

A. Authentication method
B. RTS/CTS
C. RF channel
D. SSID

Answer: A C D

Explanation

Below lists basic parameters to configure an AP

Here you will find answers to Wireless – Part 2

If you are not sure about Wireless, please read my Wireless tutorial and Basic Wireless Terminologies

Question 1

You have finished physically installing an access point on the ceiling at a newly opened office. At a minimum, which parameter must you configure on the access point in order to allow wireless clients to operate on it?

A. SSID
B. AES
C. TKIP
D. PSK
E. None of the other alternatives apply

Answer: A

Question 2

Part of the wireless LAN is shown below:

What two facts can be determined from the diagram of the WLAN shown above? (Choose two)

A. Access points in each cell must be configured to use channel 1
B. The network diagram represents an extended service set (ESS)
C. The two APs should be configured to operate on different channels
D. The area of overlap of the two cells represents a basic service set (BSS)
E. The area of overlap must be less than 10% of the area to ensure connectivity
F. There are too many hosts on this WLAN

Answer: B C

Question 3

A single 802.11g access point has been configured and installed in the center of a square shaped office. A few wireless users are experiencing slow performance and drops while most users are operating at peak efficiency. From the list below, what are three likely causes of this problem? (Choose three)

A. Null SSID
B. Mismatched TKIP encryption
C. Cordless phones
D. Antenna type or direction
E. Mismatched SSID
F. Metal file cabinets

Answer: C D F

Explanation

802.11g operates in 2.4 GHz ISM band. Some popular devices and technologies can interfere 802.11g signal:

+ Newer cordless phones
+ Bluetooth
+ Microwaves
+ Metal surface (can cause interference)
+ Antenna (can reduce wireless signal)

Question 4

Three access points have been installed and configured to cover a small remote office. What term defines the wireless topology?

A. SSID
B. BSS
C. ESS
D. IBSS
E. ASS

Answer: C

Question 5

Two workers have established wireless communication directly between their wireless laptops. What type of wireless topology has been created by these employees?

A. ESS
B. IBSS
C. SSID
D. BSS

Answer: B

Explanation

Independent Basic Service Set – IBSS (ad hoc mode) does not use an AP. It allows two devices to communicate directly.

Basic Service Set (BSS) is a single wireless LAN created with an AP and all devices that associate with that AP.

Extended Service Set (ESS) consists of multiple APs, allowing roaming in a larger coverage area.

Question 6

802.1b is being utilized in the wireless network. Which spread spectrum technology does the 802.1b standard define for operation in this network?

A. FHSS
B. IR
C. DSSS and FHSS
D. DSSS
E. IR, FHSS and DSSS

Answer: D

Explanation

Frequency Hopping Spread Spectrum (FHSS) uses all frequencies in the band, hopping to different ones. By using slightly different frequencies for consecutive transmissions, a device can hopefully avoid interference from other devices that use the same unlicensed band, succeeding at sending data at some frequencies.

Direct Sequence Spread Spectrum (DSSS) followed as the next general class of encoding type for WLANs. Designed for use in the 2.4 GHz unlicensed band, DSSS uses one of several separate channels or frequencies.

The original 802.11 WLAN standards used FHSS, but the current standards (802.11a, 802.11b, and 802.11g) do not. 802.1b uses DSSS while 802.1a & 802.1g use Orthogonal Frequency Division Multiplexing (OFDM).

(Reference: ICND1 Official Exam Certification Guide)

Question 7

Which IEEE standard is used to define Wi-Fi?

A. IEEE 802.3
B. IEEE 802.5
C. IEEE 802.11h
D. IEEE 802.11c
E. IEEE 802.11

Answer: E

Question 8

An office is using an IEEE 802.11b wireless LAN. What is the maximum data rate specified for this WLAN?

A. 11 mbps
B. 100 mbps
C. 54 mbps
D. 10 mbps
E. 1000 mbps
F. 16 mbps

Answer: A

Explanation

The maximum data rate for popular WLAN standards are listed below:

* IEEE 802.11a: 54 Mbps in the 5.7 GHz ISM band
* IEEE 802.11b: 11 Mbps in the 2.4 GHz ISM band
* IEEE 802.11g: 54 Mbps in the 2.4 GHz ISM band

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