Subject: BGP/MPLS VPNs : On an Egress PE, on which table is the label look up done ?

From: Adithya S Bhat <[email-masked]>
Date: Tue, 13 Nov 2001 17:47:06 +0530

Hi all,

WRT rfc2547bis, Section 5, Forwarding across the backbone:
"MPLS will then carry the packet across the backbone.  The egress PE
router's treatment of the packet will depend on the Label that was first
pushed on by the ingress PE.  In many cases, the PE will be  able to
determine, from this label, the sub-interface over which the packet
should be transmitted (to a CE device), as well as the proper data link
layer header for that interface. "

To determine the sub-interface over which the packet is transmitted ( to
a CE ), the PE , I assume, will have to do a label look up in some
table. I am not abel to understand, what table will this be ? ( as per
my understanding ) I am sure that this not the VRF. Juniper white paper
on rfc2547bis ( Example #1) talks of a "MPLS forwarding table", on which
the the label look up is done. Is this table similar to LIB in LDP ??,
if yes, can I assume that BGP will maintain a seperate LIB.

Am i missing something here ?

Regard
--
Adithya

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From: Robert Raszuk <[email-masked]>
Date: Tue, 13 Nov 2001 14:03:35 +0100

The most likely you will have a LFIB for such a lookup. That is the
table which is build from all label sources (LIB, BGP transported labels
... etc..).

R.

> Adithya S Bhat wrote: