[c-nsp] Catalyst 6500 Module Virtual Port Limit
matt at overloaded.net
Tue Jan 31 14:38:12 EST 2006
"Brant I. Stevens" <branto at branto.com> wrote:
> %PM-SP-4-LIMITS: The number of vlan-port instances on module 1 exceeded
> recommended limit of 1800
> %PM-SP-STDBY-4-LIMITS: The number of vlan-port instances on module 1
> exceeded the recommended limit of 1800
> This can be handled by removal of the extraneous VLANs from trunks that
> don't need a given set of VLANs.
> I was wondering if there was any more detailed information available about
> the above... I found some information about this from Networkers 2005 in
> the Datacenter Solutions Techtorial, but was looking for a bit more detail
> about this.
Scroll down slightly to the table for links to the STP limitations for a
number of platforms.
The short answer is that there is a limit on how many spanning tree
port-instances can exist on a single slot. If you have lots of VLANs and
need to trunk them to lots of ports, you probably should consider switching
to MST. Depending on your configuration, you might be able to work around
the problem (at least for a while) by ensuring that connections carrying
large numbers of VLANs are spread out and mixed with single(or low) VLAN
ports on the same cards.
Personally, I tend to run into this a lot when I use 16 port gig cards (and
have no problem with 8 port gig cards). I'll probably be switching to MST
(from RSTP+) someday soon because of this.
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