Subject: RE: 2547 BGP VPNs

From: "Suryanarayana, Ananth" <[email-masked]>
Date: Tue, 10 Sep 2002 16:13:51 -0400

I think, in any  LSP, the outer-most label corresponding to that LSP will
not be used between PH and the egress lsr and it does apply to this case as
well. and ofcourse, the inner packet has to contain a vpn label.

Ananth

-----Original Message-----
From: Sachin Kalra [mailto:[email-masked]]
Sent: Tuesday, September 10, 2002 4:03 PM
To: [email-masked]
Subject: 2547 BGP VPNs

Dear MPLS Community:

Please consider the following simple but strange scenario.
Lets say we have two directly connected PEs. Traffic is flowing from CE1 to
CE2. According to VRF table entry on PE1, for destination CE2 bottom label
is "X" and top label is "Y". And, we are doing penultimate-hop-popping (PHP)
for the LSP between PE1 and PE2. 

                            LSP
                       ========>
[CE1]------[PE1]-----------------[PE2]------[CE2]

So, my question is who does push and who does pop here? Will top label "Y"
be ever used in this scenario?

Thanks for your response,
Sachin Kalra

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Sachin Kalra
Modeling Engineer
OPNET Technologies, Inc.
(240)-497-3000 x2796
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