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TE (CCAMP|MPLS) draft-iwata-mpls-crankback-00.txt
Here is a summary of the draft-iwata-mpls-crankback-00.txt
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NAME OF I-D:
http://www.ietf.org/internet-drafts/draft-iwata-mpls-crankback-00.txt
SUMMARY:
This draft proposes crankback routing extensions for CR-LDP signaling
and for RSVP-TE signaling. Recently, several routing protocol
extensions for advertising resource information in addition to
topology information have been proposed for use in distributed
constraint-based routing. In such a distributed routing environment,
however, the information used to compute a constraint-based path may
be out of date. This means that LSP setup requests may be blocked by
links or nodes without sufficient resources. This draft specifies
crankback routing extensions for CR-LDP and RSVP-TE so that the label
request can be retried on an alternate path that detours around the
blocked link or node upon a setup failure. Furthermore, the crankback
routing schemes can also be applied to LSP restoration by indicating
the location of the failure link or node. This would significantly
improve the successful recovery ratio for failed LSPs, especially in
situations where a large number of setup requests are triggered at
the same time.
RELATED DOCUMENTS:
http://www.ietf.org/internet-drafts/draft-ietf-mpls-te-feed-01.txt
http://www.ietf.org/internet-drafts/draft-ash-ccamp-multi-area-te-reqmts-00.txt
http://search.ietf.org/internet-drafts/draft-venkatachalam-interarea-mpls-te-01.txt
http://search.ietf.org/internet-drafts/draft-dharanikota-interarea-mpls-te-ext-01.txt
http://search.ietf.org/internet-drafts/draft-kompella-mpls-multiarea-te-01.txt
http://search.ietf.org/internet-drafts/draft-bernstein-optical-bgp-00.txt
http://search.ietf.org/internet-drafts/draft-parent-obgp-01.txt
WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK
It initially fits in the TE-WG; in particular, it fits within the TEWG
Requirements
Design Team effort, and then moves to the CCAMP or MPLS WG.
We presented this I-D in CCAMP at IETF-50, and it was quite clearly sent
back to the TEWG for the development of requirements before any protocol
work would be undertaken. Therefore, we expect the following procedures for
this crankback draft:
(1) Requirements Design Team of TE-WG will specify the requirements of
multi-area TE and specify a crankback routing mechanism as one of key
mechanisms to support this.
(2) Once (1) is done, the appropriate WG (probably CCAMP WG) specifies the
detailed procedures of the crankback routing protocols. Since TE-WG will
not standardize the protocol itself but specify the requirements to other
WGs, the CCAMP WG or MPLS WG will be candidates to standardize the work.
Therefore, the situation is that initially the crankback work fits in TE-WG
and then moves to the CCAMP or MPLS WG.
WHY IS IT TARGETED AT THIS WG
See the above comments on "where does this fit in the picture". The work is
intended to provide service provider (SP) requirements for multi-area TE.
At the IETF-50 TEWG meeting, Scott Bradner initiated a "Hierarchy Design
Team", and on 5/13/2001, Bert Wijnen and Scott Bradner re-initiated a
combined network-hierarchy/survivability-techniques Requirements Design
Team, where this work still fits in.
JUSTIFICATION
1. RFC2329 makes it clear that a hierarchy may be needed to accommodate
large networks.
2. This work is intended to provide a diverse routing capability for large
scale hierarchical networks to improve a network utilization (to reduce
blocking probability). Since Scott Bradner initiated a "Hierarchy Design
Team" in TE-WG at the IETF-50 TEWG meeting, this work should be especially
important in inter-area TE environment. Bert Wijnen also re-initiated a
combined network hierarchy/survivability-techniques design team on May.13,
2001.
3. This work covers a general signaling mechanism to support different
tunnel technology (e.g. MPLS, Optical-MPLS (Lambda switching), ATM, and
FR).
Therefore, this work initially fits in the TEWG Requirements effort, and
then moves to the CCAMP or MPLS WG to specify the detailed protocol sets.
----------------------------------------------------------------
Atsushi Iwata, Ph.D.
Assistant Manager
Network Architecture TG, Networking Research Labs, NEC Corporation
4-1-1 Miyazaki Miyamae-ku, Kawasaki, 216-8555, Japan
TEL: +81-44-856-2123 (Direct), Fax: +81-44-856-2230 (Direct)
NEC-internal TEL: 8-272-3281, NEC-internal FAX: 8-272-3299
Internet E-mail: a-iwata@ah.jp.nec.com
NEC-internal E-mail: iwata@ccm.CL.nec.co.jp
*** Organization has been a bit changed since Apr.2001 ***