MPLS <draft-ietf-mpls-recovery-frmwrk-02.txt>

[Vishal Sharma <vsharma87@yahoo.com>]

NAME OF I-D

http://search.ietf.org/internet-drafts/draft-ietf-mpls-recovery-frmwrk-02.txt

SUMMARY

Multi-protocol label switching (MPLS) [1] integrates the label swapping 
forwarding paradigm with network layer routing. To deliver reliable service, 
MPLS requires a set of procedures to provide protection of the traffic carried 
on different paths. This requires that the label switched routers (LSRs) 
support fault detection, fault notification, and fault recovery mechanisms, and 
that MPLS signaling [2], [3], [4], [5], [6], [7] support the configuration of 
recovery. With these objectives in mind, this document specifies a framework 
for MPLS based recovery, covering the motivations for MPLS-based
recovery, recovery models, definitions and terminology, MPLS recovery 
principles (configuration,
path setup, resource allocation, scope of recovery, fault detection, fault 
notification, switch over
operation, and post recovery operations), MPLS recovery options, comparison 
criteria for different
recovery schemes, and some recovery requirements.

RELATED DOCUMENTS

1. A Path Protection/Restoration Mechanism for MPLS Networks
draft-chang-mpls-path-protection-02.txt
http://search.ietf.org/internet-drafts/draft-chang-mpls-path-protection-02.txt

2. Shared Backup Label Switched Path Restoration
http://search.ietf.org/internet-drafts/draft-kini-restoration-shared-backup-  
01.txt

3. Extensions to CRLDP for MPLS Path Protection
draft-owens-crldp-path-protection-ext-00.txt
http://search.ietf.org/internet-drafts/draft-owens-crldp-path-protection-ext  
-00.txt

4. Extensions to RSVP-TE for MPLS Path Protection
draft-chang-mpls-rsvpte-path-protection-ext-01.txt
http://search.ietf.org/internet-drafts/draft-chang-mpls-rsvpte-path-protecti  
on-ext-01.txt

5. A Method for Setting an Alternative Label Switched Path to Handle Fast 
Rerote
draft-haskin-mpls-fast-reroute-05.txt
http://search.ietf.org/internet-drafts/draft-haskin-mpls-fast-reroute-05.txt

6. RSVP Label Allocation for Backup Tunnels
draft-swallow-rsvp-bypass-label-01.txt
http://search.ietf.org/internet-drafts/draft-swallow-rsvp-bypass-label-01.txt

7. Reservation Protocol with Traffic Engineering Extensions: Extension for 
Label Switched Path Restoration
draft-kini-rsvp-lsp-restoration-00.txt
http://search.ietf.org/internet-drafts/draft-kini-rsvp-lsp-restoration-00.txt

8. Extensions to RSVP-TE and CR-LDP for setup of pre-established LSP tunnels
draft-hellstrand-mpls-recovery-merge-01.txt
http://search.ietf.org/internet-drafts/draft-hellstrand-mpls-recovery-merge-  
01.txt

9. Requirements for Traffic Engineering Over MPLS, RFC 2702.


WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK

  Applications         +-------+  +-------+        (new) Hour glass
  that use CCAMP: \    | TE-WG |  | PPVPN |  ...           /
                   \   +-------+  +-------+               /
                    \     +----------------------+       /
                     \    |         CCAMP        |      /
                      \   |-----------+----------|     /
                      /   |   C       |    M   --|------ IGP LSA ext
                     /    | control   | measure  |     \
                    /     +----------------------+      \
  Technologies to  / +----+ +----+ +----+ +----+ +----+  \
  measure/control:/  |MPLS| |OPT | |RPR | |ATM | | FR |...\
                     +----+ +----+ +----+ +----+ +----+


This draft fits in the MPLS WG, since it discusses the framework for MPLS-based
recovery mechanisms, and explains the various terms, categorizes the various
recovery scenarios, and details the various recovery options. In addition, it 
covers
criteria for comparing various recovery schemes.

WHY IS IT TARGETED AT THIS WG

This ID fits in the MPLS WG, since it directly addresses an
MPLS WG charter item quoted below

"6. Specify MPLS-specific recovery mechanisms to allow one label-switched path 
to be used as backup for a set of other label-switched paths, including cases 
which permit local repair. What constitutes the necessary set of MPLS-specific 
recovery mechanisms should be ascertained
through cooperation with the CCAMP and TE working groups."

This draft addresses the MPLS WG Charter item above, by providing a framework 
for
MPLS-specific recovery mechanisms that allow one/many LSPs to be backed up by
one/many LSPs.

JUSTIFICATION

This draft provides a very complete taxonomy of MPLS recovery, tying together 
the diverse
terminology, providing a solid grounding of MPLS recovery concepts, and 
providing
a basis upon which to build and evaluate recovery mechanisms.

It has already been an MPLS WG document for about nine months at this point, 
and
has undergone several revisions based upon input from the WG. At the just
concluded Minneapolis IETF, this draft received v. good support, and it was 
decided
that it should move forward for Last Call in the MPLS WG. It was also 
acknowledged
that material in this draft can, independently, provide good input to the TE WG
as well.

This is not a new work item, it has been worked on for the last 1.5 years and 
has WG
consensus.
Once the approval is given to progress this draft, it will be ready to progress 
on the
Informational RFC track.