TEWG draft-vasseur-mpls-path-computation-rsv-te-00.txt

[Jean Philippe Vasseur <jvasseur@cisco.com>]

NAME OF I-D:

RSVP Path computation request and reply messages

SUMMARY
This document describes extensions to RSVP-TE to support a new message
type called “Path computation” message to be used between an LSR and a
Path computation server which may be an LSR or an off-line tool. An RSVP
Path computation request will be used by the head-end LSR to send its
request to the path computation server. The Path computation server will
in turn sends:

-       a positive reply containing one or several paths using an RSVP Path reply message if the request can be satisfied.

-  a negative reply since no path obeying requested constraints can
be found. The path computation could also optionally suggest new

       

constraint values for which one or several paths can be found.
There are many areas where a Path computation server may be used. A
typical example being in the context of Inter-area MPLS TE where a
head-end LSR could request to a Path computation server (ABR or off-line
tool) the computation of one or several paths obeying a specified set of
constraints for a TE LSP spanning multiple areas. Another example could
be the usage of such a path computation server to compute diversely
routed paths between two end points in the context of MPLS TE LSP Path
protection or GMPLS LSP Path protection. The computation of
Multi-constraints paths requiring intensive CPU resources may be another
usage example.

RELATED DOCUMENTS:
None

WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK:
This fits into TE-WG.

WHY IS IT TARGETED AT THIS WG
This addresses specific items of the TEWG charter:

The Internet Traffic Engineering Working Group defines, develops,
specifies, and recommends principles, techniques, and mechanisms for
traffic engineering in the
internet. The working group also serves as a general forum for discussing
improvements to IETF protocols to advance the traffic engineering
function. 
The work items to be undertaken by TE WG encompass the following
categories: 
"- BCP documents on ISP uses, requirements, desires (TEBCPs)
- TE interoperability & implementation informational notes (TEIMP)
"


JUSTIFICATION
The draft directly addresses items of the charter.