Segment Routing for L2VPN?

Anoop Ghanwani anoop at alumni.duke.edu
Thu Sep 24 00:30:09 UTC 2015


It depends on what type of L2VPN we are talking about.

If we are talking about VPLS (where we learn from the data path) changes
are needed in order to make it work with segment routing.  Basically, the
VC label must be assigned and used in such a way that it indicates not only
the service for the packet, but also the PE from which it originated.  That
is because with SR, we would have lost the path (PW) that the packet used
to get to the destination PE.

If we are talking about BGP E-VPN where data path learning is not used,
then it should work with segment routing without any changes.

Anoop

On Mon, Sep 21, 2015 at 11:32 AM, Jeff Tantsura <jeff.tantsura at ericsson.com>
wrote:

> Hi,
>
> In most well designed IP routing stacks the way to get to a labeled
> (tunneled) next hop is decoupled from a service, so if a service requires
> such next hop it is upto (usually RIB) to return one (best, multiple might
> exist) which would be used for forwarding. If it is a Segment Routed one
> so it will then be used.
>
> Cheers,
> Jeff
>
> -----Original Message-----
> From: Mohan Nanduri <mohan.nanduri at gmail.com>
> Date: Sunday, September 20, 2015 at 12:59 PM
> To: Jason Lixfeld <jason at lixfeld.ca>
> Cc: "nanog at nanog.org" <nanog at nanog.org>
> Subject: Re: Segment Routing for L2VPN?
>
> >No, it works with L2VPNs also. Outer label is going to be SR label and
> >inner label is your L2VPN label.
> >
> >Cheers,
> >-Mohan
> >
> >
> >On Sun, Sep 20, 2015 at 3:23 PM, Jason Lixfeld <jason at lixfeld.ca> wrote:
> >> Hello!
> >>
> >> I've been doing some reading recently on Segment Routing.  By all
> >>accounts, it seems that the (only?) implementation for SR supports
> >>L3VPN.  Am I dumb and just missing the L2VPN bits, or is L3VPN simply
> >>the extent of the first generation?
> >>
> >> Sent from my iPhone
>
>



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