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.
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.
-> C is correct.
HSRP consists of 6 states:
|Initial||This is the beginning state. It indicates HSRP is not running. It happens when the configuration changes or the interface is first turned on|
|Learn||The router has not determined the virtual IP address and has not yet seen an authenticated hello message from the active router. In this state, the router still waits to hear from the active router.|
|Listen||The router knows both IP and MAC address of the virtual router but it is not the active or standby router. For example, if there are 3 routers in HSRP group, the router which is not in active or standby state will remain in listen state.|
|Speak||The router sends periodic HSRP hellos and participates in the election of the active or standby router.|
|Standby||In this state, the router monitors hellos from the active router and it will take the active state when the current active router fails (no packets heard from active router)|
|Active||The router forwards packets that are sent to the HSRP group. The router also sends periodic hello messages|
Please notice that not all routers in a HSRP group go through all states above. In a HSRP group, only one router reaches active state and one router reaches standby state. Other routers will stop at listen state.