Using HSRP with secondary IP addresses

[5ssandifer]

I've looked through the CCO site as well as the Cisco Press CCIE case studies book, and I can't find a clear answer to this question. We have two routers attached to one VLAN with multiple secondary addresses on the interface. We'd like to use HSRP.

One way to do this would appear to be:

RouterA

interface Vlan n

ip address w.x.y.2 255.255.255.0

ip address a.b.c.2 255.255.255.0 secondary

...

standby 20 ip w.x.y.1

standby 30 ip a.b.c.1

...

Another way would appear to be:

RouterA

interface Vlan n

ip address w.x.y.2 255.255.255.0

ip address a.b.c.2 255.255.255.0 secondary

...

standby 1 ip w.x.y.1

standby 1 ip a.b.c.1 secondary

...

Obviously I've left out some commands for brevity. My question is, is there a rule of thumb or best-practices for using multiple groups versus secondary HSRP addresses? Especially when there's only two routers? Thanks, and I can post/mail a summary if anyone's interested.

[tsettle · Accepted solution]

If you only have two routers then sticking with one group on the vlan and employing the secondary keyword should be fine. Where you would want to use multiple groups is for further redundancy and load-balancing (eg, if you have more routers).

Here's a link to all HSRP info on cisco.com:

http://www.cisco.com/pcgi-bin/Support/browse/psp_view.pl?p=Technologies:HSRP

[peter.scott]

What happens if you have 6 secondary addresses on the interface, due to migration, and you want to use HSRP. Should you use a different group number with each secondary command?

The url that you supplied doesn't go into detail about the above.

Many Thanks