Subject: [Detnet] pseudowires

From: Yaakov Stein <[email-masked]>
Date: Mon, 16 Jul 2018 14:35:38 +0000

All,

If we want to call this a detnet PW, then it has to be a PW.

In the early history of PWs there were various names for the labels.
The flow label was called the inner label, the service label, the interworking label, and the PW label.
The transport label was called the outer label, the transport label and the MPLS labels.
It took a long time for the IETF to standardize the terminology - PW label and MPLS labels (although transport labels is OK too).

The control word is almost precisely the PWE TDM control word.
The PWE TDM control word also has a sequence number that goes through the zero value (unlike the other PWs).
The only difference is that the PWE TDM CW has 4 bits for OAM indications, and 24 bits of SN.
Once again, there were bitter battles until this was sorted out.

So, either avoid the PW term altogether, or conform.

Y(J)S

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From: "Andrew G. Malis" <[email-masked]>
Date: Mon, 16 Jul 2018 11:06:05 -0400

Yaakov,

The DetNet control word conforms to figure 1 of RFC 4385, although it’s not
the preferred control word described therein. But as we know, not all PW
control words use the preferred control word format.

That said, draft-ietf-detnet-dp-sol-mpls doesn’t actually define a new PW.
What it says is:

   The basic approach defined in this document
   supports the DetNet service layer based on existing pseudowire (PW)
   encapsulations and mechanisms, and supports the DetNet transport
   layer based on existing MPLS Traffic Engineering encapsulations and
   mechanisms.

Thus, the DetNet solution is based on PWs, but doesn’t define a new PW. In
particular, we don’t (yet) expect to use targeted LDP for DetNet label
advertisement (although we could, but that’s a decision to make further
down the line) and we haven’t (yet) asked IANA to allocate a new PW type.

We (the Detnet data solution team) decided to use terminology that is
consistent with the DetNet architecture. So IMHO there’s no probem with
using the particular terms service label and transport labels. They are
perfectly understandable as defined iin the draft, and the service label in
particular directly relates to the DetNet service layer defined in the
DetNet architecture.

Cheers,
Andy

On Mon, Jul 16, 2018 at 10:35 AM, Yaakov Stein <[email-masked]> wrote:

> It took a long time for the IETF to standardize the terminology – PW label
> and MPLS labels (although transport labels is OK too).
>
>
>
> _______________________________________________
> detnet mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/detnet
>
>