Subject: [CCAMP] Multiple overlay netwroks case is not properly answered by RFC4208

From: "Elfassy, Nitsan (NSN - IL/Hod HaSharon)" <[email-masked]>
Date: Sun, 3 Apr 2011 18:13:24 +0200

Dear RFC4208 editors, 

Your help with the following will be most appreciated:

RSVP-TE extensions for supporting the overlay model do not seem to
properly address the multiple overlay networks use case. Or in fact
leave one specific use case not handled. Read inline.

Let us assume the following: (the figure below may help) 
We have a Core Network that serves two different overlay networks
{Overlay Network A, Overlay Network B}.
Two sets of {CN, EN} pairs exist, each of which from an independent
address pace. One for serving overlay network A and another for Overlay
network B.
PE1 and PE2 are two Core Nodes, Each of which connected with two
different peer Edge Nodes as follows:
PE2 happens to be connected to two edge nodes who happen to share the
exact same numbered IP address 10.0.1.1
Let us assume that an Edge Node from Overlay network A wishes to set an
LSP to 10.0.1.1 (another overlay network A member) behind PE2:

Upon reception of the Path message from PE1, PE2 cannot know which among
the two EN peers is the edge node to which the LSP is destined.  RFC4208
does not seem to provide the tools to resolve this ambiguity for PE2.

Please help me understand what have I missed here.

Thanks, 
Nitsan Elfassy, NSN  

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