[c-nsp] Maximum spannig tree instances

[Tim Durack]

On Sat, Jul 18, 2009 at 4:06 PM, Matt Buford <matt at overloaded.net> wrote:

> On Fri, Jul 17, 2009 at 11:55 PM, Tim Stevenson <tstevens at cisco.com>
> wrote:
>
> > The 6500/sup720 on 33SXI supports 100K logical ports in MST, and 12K in
> > RPVST. That's up from 50K/10K in every prior release.
> >
>
> Did the per-slot limitation change too?
>
> N7K supports 75K in MST & 16K in RPVST today. There are no per-module
> > limitations on N7K.
> >
> > Those numbers are based on the requirements we expressed to QA/system
> test
> > prior to FCS. The original numbers were confirmed prior to 33SXI was
> > released. Since then, we have not had a customer requirement/request to
> > support more, so frankly we have not felt compelled to go and requalifify
> > for anything greater. Would be curious to know how many logical ports you
> > are running today & in what protocol?
> >
>

Whilst we are sort-of happy with MST in our environment, I think what this
discussion shows is that STP is past it's sell-by date. It works, but is
somewhat brittle.

It will be interesting to see what the various L2MP/TRILL initiatives
produce. Googling around for "Cisco Overlay Transport Virtualization" turns
up an interesting looking patent. I doubt we'll have hardware that supports
this anytime soon (maybe Nexus.)

Tim:>