Technical Summary
This document fixes a problem relating to when in the establishment of an LSP,
traffic may be sent on an LSP.
When certain RSVP-TE optimizations are implemented, ingress LSRs can
receive RSVP RESV messages before forwarding state has been installed
on all downstream nodes. According to the RSVP-TE specification, the
ingress LSR can forward traffic through an LSP as soon as it receives
a RESV message. However, if the ingress LSR forwards traffic through
the LSP before forwarding state has been installed on all downstream
nodes, traffic can be lost.
The document describes new procedures called LSP Self-ping. When an
ingress LSR receives an RESV message, it can invoke LSP Self-ping
procedures to ensure that forwarding state has been installed on all
downstream nodes.
LSP Self-ping is an extremely light-weight mechanism. It does not
consume control plane resources on transit or egress LSRs.
Even though there is a naming similarity between "MPLS Self Ping" and "MPLS
LSP Ping" the protocols really has nothing in common.
The protocols diagnose a different set of problems, listen for input on different
UDP ports and behave differently. The only thing that they have in common is
that they are named similarly.
Working Group Summary
The only thing worth mentioning here is that there were a lot of
discussion taking place at the time when the draft was accepted as
a working group document. Especially there were discussion on
whether there is an overlap with BFD mechanisms in documents
that are developed in in the BFD working group.
It is understood that on a very high level such an overlap exists, but
when we get down to details this draft is quite separate from what is
is done in BFD.
The MPLS working converged on the understanding that this draft
is very specific for LSP establishment with RSVP-TE and fills a gap
that needs to be filled. The BFD mechanisms are much more generic.
The support for the draft in the wg is quite good, and the progress through
the working group has been easy, once the discussion around adopting the
draft as a working document had converged.
Document Quality
Yes there is at least one implementation. We have started an
implementation poll and will update the Write-Up once we have
further information.
The review of the document is quite good, it has been through
the mpls review team review and been discussed on the mailing
list.
No further specialist reviews are necessary.
Personnel
Loa Andersson is the Document Shepherd.
Deborah Brungard is the responsible AD.