[c-nsp] 6500/Sup720 and SVI xconnect?

[Peter Rathlev]

On Tue, 2010-04-27 at 18:31 +0200, Asbjorn Hojmark - Lists wrote:
> On Tue, 27 Apr 2010 10:58:27 +0200, you wrote:
> > > Also, on a 7600 (SR software), you can run Mux UNI (a trunk with
> > > VLANs and sub-interfaces on the same interface), even on LAN
> > > cards. I don't remember off the top of my head if that's supported
> > > on the 6500.
> >
> > It is, but won't help. You still can't put the xconnect configuration 
> > on the SVI.
> 
> The way I understood the question, that was not needed.

I did actually mean xconnect configuration on a SVI. :-)

We use MUX UNI with success on 6500/Sup720/SXI in several places. Where
we need to also have L3 functionality in the same VLAN we currently use
port mode EoMPLS and a cable looping between this and a switchport trunk
on the same box. This gives us the "poor mans" combination of EoMPLS and
L3 support on the same box.

It only works point-to-point though, so each PoP has two boxes, each
having a connection to one other PoP. The drawbacks to this are several:

 * It only supports a simple ring topology

 * There's no (easy) way to have the L2 domain (STP) know anything
   about the underlying actual topology, which means it's a pain to
   control. (TE on the EoMPLS LSP could solve this I guess, just
   haven't had the time to test and deploy it.) 

 * It costs two extra physical interfaces, apart from the regular
   core facing ones. Of course the LAN card interfaces are cheap
   compared to ES+/SIP-600.

We have some "system architects" that think the best way to design
systems is with some reliance on L2 connection even with the data
centres several hundred KMs apart. :-|

We're currently looking at what it would to take (i.e. how much it would
cost) to make this a more clean solution.

-- 
Peter