Re: About LSP Stiching

[Arthi Ayyangar <arthi@juniper.net>]

Amit,

> 	There is no way for LSP segment head node, to identify that a
> Outif selected is a LSP Segment for setting up E2e LSP.
---> What do you mean ? Why would the head-end of an LSP segment not know
that selected nexthop is the LSP segment ? It is the head-end of the LSP
segment selecting what you call Outif.


> 	That is Some extension will be needed to RSVP that will allow RSVP
> message(for E2e LSP) processing at LSP segment head node to be processed
> according to the Sticthing needs.
------> I don't think there is any need for any more extensions..see my
explanation above and below.


> 	For Eg: LSP1-2 is an E2e LSP setup over an LSP segment LSPA-B.
>
> 	1-----A--D---E--B-----2
>
> 	Now if A gets the Path message for LSP1-2, and A selects LSP
        segment LSPA-B as outif.
> 	Then how does RSVP(at Node A) identify that the outif selected is
        a LSP segment?
-------> A is doing nexthop (what you call outif) selection, A is the
head-end of LSP segment. A knows that nexthop is an LSP segment.


> 	Also when A receives Resv for LSP1-2(from B), how can it ignore
>     Label in it.
> 	There should be a way to determine at node A, that a LSP segment
> is in use.
-----> A chose to stitch the e2e LSP to the LSP segment in the first place.

thanks,
-arthi



> 	One possible way could be that Resv message for LSP1-2 should be
> sent(by B) with some special Label value.
> 	This Label value should indicate the node A that the Resv is
> received for a TE-Link(of type LSP Segment).
> 	This will help node A to ignore Label value in Resv msg for E2e
> Lsp LSP1-2.