The MPLS WG Archive

["O'Connor, Don" <don.oconnor@us.fujitsu.com>]

Stewart

The current draft-bryant does not add any new functionality to existing PWE3 RFC / ID for transport requirements. It should not become a wg draft until there is evidence that there is a commitment to support some new functionality to address transport specific requirements in Appendix A of draft-bryant. More specifically these are the OAM and Survivability requirements 21 - 27 in Appendix A. As a minimum there should be some sections and initial text for

1) Bidirectional 1:1 linear protection switching for pseudowires and associated PSN tunnel

- This protection switching is coordinated by enhancements to the applicable layer OAM protocol - i.e. VCCV and LSP Ping

For more detailed requirements and reference please see ITU recommendation G.8131

2) Pseudowire and PSN Tunnel Transport OAM Extensions

- My suggested minimum subset extensions would be - ME Levels, MEP / MIP, PM measurement, AIS / RDI , Tandem Connection Monitoring (i.e. - for a multi-hop PW and / or PSN tunnel the ability to enable a continuous continuity check for one / N / all hops), and Synchronous Status Message

Please also see my replies in line to your email below

Regards

Don


-----Original Message-----
From: Stewart Bryant [mailto:stbryant@cisco.com]
Sent: Friday, March 23, 2007 7:13 PM
To: O'Connor, Don
Cc: mpls@ietf.org; pwe3
Subject: Re: [mpls] RE: [PWE3] Fwd:
I-DACTION:draft-bryant-pwe3-mpls-transport-00.txt


Don

A draft does not need to be complete for it to be
accepted as a WG draft, it needs to be a suitable
platform that the WG can use to move forward.

> IETF is extending MPLS technology all the time. The extensions 
that I see that are required are:

1) transport OAM enhancements

Given that the existing PWE3 OAM functions are adequate
for our own purposes, what is special about the transport
environment that requires extensions?

It is not appropriate to list alternative OAM protocols,
PWE3 needs to know what specific additional functionality
it needs to provide a comprehensive OAM design.

[Don] ME Levels, MEP / MIP, PM measurement, AIS / RDI, Tandem Connection Monitoring, and Synchronous Status Message

2) support for transport protection switching

PWE3 has already started work on protection. What
requirements exist in the transport network that are not
addressed by the proposed work?

[Don] Linear bidirectional 1:1 protection switching for both pseudowire and PSN tunnel. This protection switching should be coordinated by updates to VCCV and LSP Ping. The abstract to draft-bryant implies that it specifies a complete transport network solution. So transport orientated protection switching should be included in draft-bryant. I could contribute text

Would you be prepared to contribute text to a PWE3 protection
requirements draft?

[Don] draft-ietf-pwe3-ms-pw-requirements-05.txt already addresses a number of the relevant requirements. If we agree to have a transport protection switching section in draft-bryant, I can suggest some additional transport orientated requirements for ms-pw-requirements. Note that was also need to address PSN tunnel layer linear 1:1. RFC 3469 provides a superset of the transport PSN tunnel protection switching requirements.

With respect to existing protection work in PWE3 as evidenced by draft-muley-pwe3-redundancy-01.txt and draft-muley-dutta-pwe3-redundancy-bit-00.txt, some of addressed applications may be applicable for mpls transport (e.g. multi-homing) but I do not believe that the redundancy bit is applicable. Transport mpls linear protection switching is coordinated by the OAM protocol. For reference please see G.8131.  

3) GMPLS - ASON control plane enhancements (using the procedures
that CCAMP has in place with ITU)

The control plane design for PWE3 over MPLS and for MPLS is
a proven design that is widely deployed. How is the existing
designs unsuitable, and what additional requirements does a
transport environment have that are not satisfied by that
design.

[Don] QOS / Traffic Engineering for multi-segment PW. My opinion is that for transport mpls draft-raggarwa-rsvpte-pw-03.txt, provides a better solution than LDP based segmented pseudowires.

- Stewart

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