Subject: Comment on protocol layering draft

From: [email-masked]
Date: Fri, 5 Jul 2002 13:42:16 +0100

Folks,

Figure 11 of the protocol layering draft 
(draft-ietf-pwe3-protocol-layer-00) shows how the draft-martini 
encapsulation maps to the proposed layering structure for PWE3. However, 
this has not yet been formally chosen by the working group as the encap to 
go with for a number of the Layer 2 services. 

I think it would be better if each individual service draft had to show 
that it conforms to the PWE3 layering document, and for the layering draft 
to be independent of any specific encapsulation format. Please could we 
therefore remove the specific mapping to the draft-martini encapsulation 
shown in Figure 11.

Best regards,

Matthew

---

From: Stewart Bryant <[email-masked]>
Date: Fri, 05 Jul 2002 15:24:30 +0100

The CW that we used was really a generic outline rather than the one 
from the Martini draft.

Does any group have plans to use a CW that does not conform to this 
outline: 

ie More than 4 bytes of control information?
ie Extra field that they regard as being generic?

If so perhaps we could modify the outline below to provide
a more appropriate generic MPLS CW. Is there any chance of us 
agreeing some generic format for the MPLS CW in Japan?

When it comes to the next round of cleanup, we could do one of two
things, either delete this text entirely as Matthew suggests, or
we could move it (and the IP equivalent) to a non-normative
annex. Any preferences?

Stewart

          +---------------------+
          |      Payload        |
          /=====================\
          H Payload Convergence H-----------------+
          H---------------------H                 |
          H       Timing        H                 |
          H---------------------H                 |
          H     Sequencing      H------------------------------------+
          \=====================/                 |                  |
          |  PW Demultiplexer   |---+             |                  |
          +---------------------+   |             |                  |
          |  PSN Convergence    |-----------------------+----+----+  |
          +---------------------+   |             |     |    |    |  |
          |        PSN          |-+ |             v     v    v    v  v
          +---------------------+ | |  +--------------------------------+
          |    MAC/Data-link    | | |  |      Flags   |Frag| Len |Seq # |
          +---------------------+ | |  +--------------------------------+
          |       Physical      | | +->|          Inner Label           |
          +---------------------+ |    +--------------------------------+
                                  +--->| Outer Label or MPLS-in-IP encap|
                                       +--------------------------------+

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---

From: [email-masked]
Date: Fri, 5 Jul 2002 17:52:13 +0100

Stewart,

Thanks for your response. I don't know of any drafts that have more than a 
4 byte control word, but there are drafts (e.g. 
draft-fischer-pwe3-atm-service) that have a different order of the 
flags/length/sequence number in the control word, but do align with the 
correct layering. So I think that at least the contents of the control 
word should not be shown here.

Regards,

Matthew

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Subject:        Re: [PWE3] Comment on protocol layering draft

Stewart

          +---------------------+
          |      Payload        |
          /=====================\