[j-nsp] BGP RR in MPLS VPN

[Scott Morris]

If your next hops are the loopbacks of the PE's, you can always have those
in your inet.3 table.  But you are correct, if the RR cannot resolve that
next hop then the route will not be used or sent to other peers.

If you do something like next-hop-self on the RR, then you most definitely
will need to involve the RR in your LSPs.  But otherwise, it can be avoided.

While it would be nice if there were a way to disable that check, according
to JunOS docs, it still notes that the RR is not "supported" for VPN routes
for this reason.  (e.g. this is workaround, not an officially supported
thing at this time!)

It's nice to do this to have the LSPs where it makes sense, and simply use
the RR as an efficient mechanism to exchange routing information.

Scott 

-----Original Message-----
From: juniper-nsp-bounces at puck.nether.net
[mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Anton Smith
Sent: Tuesday, October 10, 2006 7:39 AM
To: juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] BGP RR in MPLS VPN

Hi,

Senad wrote:
 > Scott, I AFAIK, unless P (RR) has PE's loopbacks (if IBGP) or physical >
links (whatever is BGP NH) in its inet.3 table, the VPN routes will be >
hidden. Therefore, we do need LSPs from PE to RRs. Plz, correct me if >I am
wrong. It's been a while and can't jump on boxes right now. HTH,  > Senad

 > --- Scott Morris <swm at emanon.com> wrote:
 > > No.  The RR will simply pass around routing  > > information.  As long
as the  > > next-hop IP remains unchanged (PE to PE) then your  > > LSPs
have no need to go  > > through the RR.
 > >
 > > HTH,
 > >
 > > Scott

Senad, I think you are correct. If the next-hops are not resolvable on the
RR it won´t re-advertise them.

Does anyone know if there is a reason for this? And if so, are there any
plans to put some kind of override knob in for this situation? Does the P
really need LSPs to the PEs? Just because the P cannot resolve the next-hop
does not necessarily mean the PEs will be unable to.

Regards,
Anton
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