Subject: [PWE3] Generic PW - Is there a need?

From: Danny McPherson <[email-masked]>
Date: Mon, 30 Jan 2006 10:50:30 -0700

Folks,
We would like to start a discussion on whether the PWE3
WG should work on the definition of a generic packet PW.

The driver for this work is threefold:

1) The need for a PW to support the IPLS work in the L2VPN
WG

2) The need to provide an MPLS PW to satisfy the same need
as the IP PW proposed in the L2TPext WG

3) The need to provide PW to transport MPLS PWs

This type of PW is generally needed where it is required to
interconnect ACs with two (actually or potentially) disparate
Layer 2 protocols.

Generally one would use a Layer 3 service to provide this,
but the use of a Layer 2 service allows greater decoupling
between the client and transport networks.

The types of packets that need to be carried over a generic
packet PW are know to be (are there others?):

IPv4
IPv6
IS-IS
MPLS
Compressed IP

In all cases the payload would be carried over a PW with a CW
to allow ECMP suppression and the discrimination of different
packet types multiplexied over the PW, for example IPv4 packets
and IS-IS protocol packets. Because a CW was used the EoS bit
would need to be set in the transport label stack, as well as in
the client label stack.

A generic PW would be supported by its own OAM mechanism
(VCCV) which would be different from any client OAM
mechanism.

One application for the service would be a SP transit domain
in which it was desired that there was no interaction between
the client and transport network protocols (e.g., MPLS LSP
transport services w/no LDP interaction between the transport
and client networks).

The work within PWE3 would be a short encapsulation specification
and applicability statement.

Where the generic packet PW payload was MPLS the PW would be
transparent to the MPLS client layer and not an extension of the
MPLS heirachy. This would need to be made clear in the
applicability statement.

Do folks here have comments either way on the utility, application
and/or requirement for this (i.e., if you're in favor or against please
make it known to the list)?

Thanks!

-danny & Stewart 

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From: Craig White <[email-masked]>
Date: Mon, 30 Jan 2006 13:41:10 -0500

Just as I said when this was brought up before, I think this is very
applicable to our work. This generic packet PW, will be very useful in many
situations and is something that we should define.

-craig

> WG should work on the definition of a generic packet PW.

*SNIP*

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From: "Thomas D. Nadeau" <[email-masked]>
Date: Mon, 30 Jan 2006 14:41:20 -0500

I think this stuff is very useful.
Lets just make sure that we get the OAM
right at the start, and not do it as an
afterthought later.

	--Tom