Subject: I-D Action: draft-dai-mpls-rsvp-te-mbb-label-reuse-00.txt

From: [email-masked]
Date: Mon, 09 Mar 2015 16:40:52 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.

        Title           : MPLS RSVP-TE MBB Label Reuse
        Authors         : Minjie Dai
                          Ebben Aries
                          Muhammad Nauman Chaudhry
	Filename        : draft-dai-mpls-rsvp-te-mbb-label-reuse-00.txt
	Pages           : 7
	Date            : 2015-03-09

Abstract:
   The concept of "make-before-break (MBB)" while rerouting MPLS RSVP-TE
   tunnels is discussed in [RFC3209].  In the procedure that is
   outlined, the behavior of downstream label assignment for the new LSP
   (new tunnel instance) is not well defined.  As a general practice, a
   different label is assigned by each downstream router and advertised
   to the upstream router in the RESV message for the new LSP; this
   results in a separate end-to-end data-plane path for the new LSP
   (with the exception of PHP LSPs or UHP LSP with explicit label on the
   last hop).  This practice allows independent end to end LSP path
   data-plane verification for each tunnel instance.  The consequence of
   this practice is that the label entry gets added/deleted in the LFIB
   at every non-ingress router along the LSP path during MBB.  Also, the
   ingress router would need to update all the applications using this
   LSP when switching to the new tunnel instance, as the new tunnel
   instance uses different outgoing label.  This in turn may also cause
   other elements of the network which are dependent on the LSP to do
   the update.

   Such network churn can be avoided/minimized if the same label can be
   re-used (kept intact) wherever it is affecting neither the routing
   functionalities nor the data path verification of each instance.  In
   addition, whenever label is reused, the setup time for the new tunnel
   instance would be faster because there is no need for the transit
   routers along the path of the new LSP to wait for the new LFIB entry
   to be added.  This document proposes a set of procedures to
   facilitate label reuse when there is a total or partial path overlap
   between the two tunnel instances during MBB.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-dai-mpls-rsvp-te-mbb-label-reuse/

There's also a htmlized version available at:
http://tools.ietf.org/html/draft-dai-mpls-rsvp-te-mbb-label-reuse-00

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