Subject: using MPLS for protection switching

From: Jim Sullivan <[email-masked]>
Date: Wed, 12 Jan 2000 10:12:42 -0500

In several threads people have mentioned using MPLS for
protection switching. Can someone tell me what this is ? 
Is there a specification that describes it ?   
Thanks Jim

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From: "Stephen Shew" <[email-masked]>
Date: Wed, 12 Jan 2000 11:01:10 -0500

There are a number of I-Ds that discuss aspects of protection using MPLS.  These
include:
<draft-makam-mpls-protection-01.txt>
<draft-haskin-mpls-fast-reroute-01.txt>
<draft-krishnan-mpls-reroute-rsvpext-01.txt>
<draft-swallow-rsvp-bypass-label-00.txt>
<draft-andersson-reroute-frmwrk-00.txt>
<draft-shew-lsp-restoration-00.txt>

Broadly speaking, there are two types of protection mechanisms: protecting an
LSP at a time, or protecting a link over which multiple LSPs are being carried.

--
Stephen Shew                Voice: 613-763-2462   Fax: 613-765-3165
Nortel - Carrier Packet Solutions  email: [email-masked]
P.O. Box 3511, Station C
Ottawa, ON  K1Y 4H7

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From: "Peter Ashwood-Smith" <[email-masked]>
Date: Wed, 12 Jan 2000 11:30:41 -0500

> Is there a specification that describes it ?

  The basic concept is to use another MPLS tunnel to backup
either 1 or many other MPLS tunnels. This can be done with
a hot standby that either maps one to one or one to many
with the backed up tunnels. If one implements a backup so
that it protects a single or small number of hops of a 
longer LSP, you have something similar to protection 
switching. In essense MPLS gives you the possibility to
implement a whole range of backup strategies 
from local segment 1:n backup (similar to protection switching)
all the way up to 1:1 end to end backup.

  There have been a couple of drafts proposing mechanisms
to do this and a draft that proposes a framework for these
mechanisms.

  Cheers,

  Peter Ashwood-Smith