Subject: Signalling O&M MPLS packets

From: Kireeti Kompella <[email-masked]>
Date: Mon, 5 Jun 2000 16:51:36 -0700 (PDT)

Neil,

> Before I looked at the TTL option, this was the basis of what I had
> orginally planned.  In my orginal analysis I considered parsing the label
> field into a 16 bit true label field and a 4 bit payload ID field.

Before we go too far down the "TTL option" path (or reinterpreting
the label bits), consider the fact that the format of a label is
pretty much fixed; there are MPLS networks carrying production
traffic with this label format, as well as various protocol stacks
and hardware designs that incorporate this label format.

A change in the interpretation of the TTL field (or any other bits
in a label) at this point is not something to be undertaken lightly.

> Another option, which is what I think you and Thomas Theimer are suggesting,
> is to assign a special OAM 'alert' label.

This is a much more acceptable approach.

Thanks,
Kireeti.

---

From: [email-masked]
Date: Tue, 6 Jun 2000 01:29:39 +0100

Kireeti,

Thanks for this observation on backwards compatibility below.

 I fully agree we should not do anything which is not essential for this
reason.

Regards, Neil