The MPLS WG Archive

[Robert Raszuk <raszuk@cisco.com>]

Sorry for being late ...

Two comments:

1. A lot of people mentioned that there is no need to run IBGP on core
routers with mpls-vpns or just prefix/tunnel based mpls in the core.
That is true but only for _unicast_ traffic. One I think quite important
point is no one has mentioned that if one is providing global multicast
service full table in every router is needed for RPF check. This will
hold until one comes with good proposal & implementation of mpls for
multicast.

Now said this there are two ways to keep rolling until this happens:

* Keep the ipv4 ibgp there, automatically populating routing table &
forwarding table with 85K entires which may not be used at all for
forwarding

* Turn existing ipv4 ibgp mesh into multicast-BGP full mesh and
propagate the full table for the purpose of m-cast RPF check while not
"waist" RIBs/FIBs RAM space.


2. Satoru Matsushima said:

> When a LSP of PE to PE broken, BGP has no way of LSP broken.
> I think this is one of most seriously problem of BGP/MPLS VPN.

Not true when we are talking about prefix based LSPs. If you are using
prefix based LSPs they will disappear only if ip route to bgp next hop
will disappear what in turn will cause bgp route withdrawn (invalid bgp
next hop) at a periodic scanner. If there is no route - you will not be
able to route anyway - no miracles here.

If you are talking about tunnel based LSPs (TE for example) - you have
got what you have configured. I would advise caution configuring your
network this way and I don't think this particular case can justify
calling a mpls-vpn architecture as a "serious problem".

R.