32 HSRP groups supported by 3750

[ace-cco]

I have a big problem,

the 3750 should support 32 HSRP groups, but if i configure this groups, there are only 17 groups possible, when i configure HSRP group number 18, there is the message

%Platform does not support more than 32 HSRP groups

whats wrong,

i tried to configure more than 1 vlan-interface in one HSRP group, but it is all the same

thanks for reply

[Kevin Dorrell]

I don't know about the 3750, but on the 3550 there are additional implementation-derived limitations on the re-use of HSRP groups on different VLANs. The algorithm is quite complicated, but see the links below. Now, I can find these limitations in the 3550 documentation but not in the 3750. But I don't know whether the same limitations apply to the 3750 but they simply have not documented it.

Here are the doc references, FWIW:

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12225se/3550scg/swhsrp.htm#wp1044151

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3750/12225se/3750scg/swhsrp.htm#wp1044151

Does the limitation described in the 3550 document fit your scenario?

Kevin Dorrell

Luxembourg

[andrew.butterworth]

Is there any reason why you need different HSRP group numbers? Are you bridging between VLANs? Are you connecting to another Vendors switch that doesn't create a CAM table per VLAN?

If you are not bridging between VLAN's or connecting to another Vendors switch then just use the same HSRP Group number:

interface VLAN 10

ip address 10.1.1.1 255.255.255.0

standby 10 10.1.1.254

!

interface VLAN 20

ip address 10.2.1.1 255.255.255.0

standby 10 10.2.1.254

!

interface VLAN 30

ip address 10.3.1.1 255.255.255.0

standby 10 10.3.1.254

!

etc

Andy