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RE: I-D ACTION:draft-ietf-ccamp-lsp-stitching-01.txt



Hi Arthi, JP

Thanks for this new revision that sounds really good

I have two commments:

-In section 4.1.2 you partially describe bidirectional LSP stitching procedure.
You mention that an Upstream Label MUST NOT be allocated by the end-to-end LSP on the LSP segment, which is OK.
But then how the LSP-Segment Egress will now that the end-to-end LSP is bidirectional? What about defining a flag in the Attributes Flags TLV of the LSP_ATTRIBUTE object so as to indicate that the LSP is bidirectional?
Also the selection of the LSP segment in case of bidirectional LSP should be detailed (e.g. If the end-to-end LSP is bidirecitonal then 
the LSP-segment MUST be bidirectional. Also shall we allow that two unidrectional end-to-end LSP use the same bidirectional LSP segment (one in each direction)?

-At the end of section 4.2.5 you mention that LSP-Segment failure or maintenance SHOULD be treated as a failure event for the end-to-end LSP. I agree for LSP-Segment failure but not for LSP-Segment maintenance. LSP-Segment maintenance should be treated as TE-link maintenance for the end-to-end LSP, and procedures defined in GMPLS graceful TE-link shutdown draft may be useful (Specific RSVP error code and TE-link attribute)...

Hope this helps,

Best Regards

JL


> -----Message d'origine-----
> De : owner-ccamp@ops.ietf.org 
> [mailto:owner-ccamp@ops.ietf.org] De la part de 
> Internet-Drafts@ietf.org
> Envoyé : vendredi 15 juillet 2005 21:50
> À : i-d-announce@ietf.org
> Cc : ccamp@ops.ietf.org
> Objet : I-D ACTION:draft-ietf-ccamp-lsp-stitching-01.txt 
> 
> A New Internet-Draft is available from the on-line 
> Internet-Drafts directories.
> This draft is a work item of the Common Control and 
> Measurement Plane Working Group of the IETF.
> 
> 	Title		: Label Switched Path Stitching with 
> Generalized MPLS Traffic Engineering
> 	Author(s)	: A. Ayyangar, J. Vasseur
> 	Filename	: draft-ietf-ccamp-lsp-stitching-01.txt
> 	Pages		: 19
> 	Date		: 2005-7-15
> 	
> In certain scenarios, there may be a need to combine together two
>    different Generalized Multi-Protocol Label Switching (GMPLS) Label
>    Switched Paths (LSPs) such that in the data plane, a single end-to-
>    end (e2e) LSP is achieved and all traffic from one LSP is switched
>    onto the other LSP.  We will refer to this as "LSP 
> stitching".  This
>    document covers cases where: a) the node performing the stitching
>    does not require configuration of every LSP pair to be stitched
>    together b) the node performing the stitching is not the egress of
>    any of the LSPs c) LSP stitching not only results in an end-to-end
>    LSP in the data plane, but there is also a corresponding end-to-end
>    LSP (RSVP session) in the control plane.  It might be possible to
>    configure a GMPLS node to switch the traffic from an LSP 
> for which it
>    is the egress, to another LSP for which it is the ingress, without
>    requiring any signaling or routing extensions whatsoever, 
> completely
>    transparent to other nodes.  This will also result in LSP stitching
>    in the data plane.  However, this document does not cover this
>    scenario of LSP stitching.
> 
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-ietf-ccamp-lsp-stitc
hing-01.txt
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