[c-nsp] Maximum spannig tree instances

[Peter Rathlev]

On Tue, 2009-07-14 at 17:56 +0200, Thomas Habets wrote:
> On Tue, 14 Jul 2009, Peter Rathlev wrote:
> > My bold guess would be that the system limit for number of STP
> > instances is 10000/13000 total virtual ports (RPVST/PVST).
> 
> 10'000 is what the documentation said, yes
> http://www.cisco.com/en/US/solutions/ns340/ns394/ns50/net_design_guidance0900aecd806fe4bb.pdf
> 
> > Whether having 1800+ STP instances on the same switch is a good idea
> > i something completely different. :-)
> 
> Not STP instances. 48 ports of aggregation with 50 VLANs will get you
> well over the virtual port limit. It's not "STP on 1800+ VLANs", and
> not unheard of.

That's for virtual ports yes. But that's not the same as STP instances.

As my lab test shows you can easily exceed 1800 RSTP instances. I kept
each of two modules on 1799 virtual ports, but with different VLANs on
each. Having more STP instances than VLANs would of course be difficuly,
so i guess the limit is around 4000 instances.

That's for RSTP. I'm afraid I don't know much about MST.

Regards,
Peter