hsrp

[carl_townshend]

Hi all

Can anyone tell me why we have different hsrp groups on routers, why do we need them, should you normally have each interface in a different group ?

[gearnsc]

You can configure multiple groups on an interface, so if you have a secondary ip subnet on the same layer 2 segment you can have an hsrp for each subnet.

[Edison Ortiz]

Load Sharing

http://www.cisco.com/warp/public/619/7.html

[royalblues]

In Addition to Edison's post, An interface can belong to multiple HSRP groups, and the same HSRP group can be applied to different interfaces.

The switch supports HSRP MAC addresses for up to 16 unique HSRP groups. Because each group address can be used on up to 16 Layer 3 interfaces, the maximum number of HSRP interfaces is 256.

Each of the 16 HSRP MAC addresses can be used by 16 consecutive Layer 3 interfaces because each address is associated with a group of VLANs by using a 4-bit mask.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_19_ea1/configuration/guide/swhsrp.html#wp1044151

HTH

Narayan