HSRP groups on dual MSFC2's of Catalyst 6509 with redundant supervisors.

[ksowell]

Is it necessary to use unique group ID's for individual vlans instead having them all in the default group 0 on dual MSFC2's. Is there any advantage to using unique group ID's?

[pmajumder]

No it's not required. However, on the MSFC2's you are limited to a total 16 HSRP groups. See below regarding potential issues with using the same HSRP groups on multiple interfaces.

http://googleweb-1.cisco.com/search?q=cache:http://cco-rtp-1.cisco.com/en/US/customer/products/hw/switches/ps700/products_qanda_item09186a008011c6bb.shtml+hsrp+groups&ie=UTF-8&site=CDC&output=xml_no_dtd&client=CDC&proxystylesheet=CDC&oe=UTF-8

[ahojmark]

No it isn't neccessary to use individual IDs. In fact, you only have 16 groups to chose from on that platform, so depending on the number of VLANs that you have, you may not be able to.

The only possible advantage is that you'd get different MAC addresses for the different groups (for example when sniffing, and when internetworking with old/stupid switches that only have a single L2 forwarding table, and will get confused about the same MAC address being on different VLANs).

-A

[pmajumder]

I also read somewhere that because of having the same mac address, there could be potential issues with having bridge groups defined on those vlan interfaces sharing the same HSRP group. Can someone confirm that?

Regards

Pradeep