[c-nsp] Catalyst with HSRP

[Tom Zingale (tomz)]

Is it safe to assume the same question and answer apply for VRRP as
well, and that SVI's for VLANs trunked over the same physical interface
count as "multiple interfaces" in reference to the above Q&A?  

Yes SVIs for vlans count as multiple interfaces.

> -----Original Message-----
> From: Jon Lewis [mailto:jlewis at lewis.org]
> Sent: Tuesday, July 17, 2007 4:15 PM
> To: Tom Zingale (tomz)
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Catalyst with HSRP
> 
> On Tue, 17 Jul 2007, Tom Zingale (tomz) wrote:
> 
> > The 3560e/3750e, we can support up to 32 groups but each group can
be
> > supported across multiple vlans. Therefore, you can have one group
on
> > multiple VLAN's but it will only count once toward the 32 group
limit.
> 
> Q. What is the implication of the use of the same HSRP group ID on
> multiple interfaces?
> 
>      A. When you define the same HSRP group ID on multiple interfaces,
they
> all share the same HSRP virtual MAC address. In most modern LAN
switches,
> there are no issues because they maintain a per-VLAN MAC address
table.
> However, if your network contains any third party switches which
maintain
> a system-wide MAC address table regardless of VLAN, you may experience
> problems.
> 
> Is it safe to assume the same question and answer apply for VRRP as
well,
> and that SVI's for VLANs trunked over the same physical interface
count as
> "multiple interfaces" in reference to the above Q&A?  So given a
network
> of reasonably modern cisco gear, there's no compelling reason to use
> different HSRP or VRRP group numbers on any number of SVIs unless you
need
> to support multiple groups within a single SVI / vlan subinterface?
> 
> ----------------------------------------------------------------------
>   Jon Lewis                   |  I route
>   Senior Network Engineer     |  therefore you are
>   Atlantic Net                |
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