Subject: PWE3 congestion

From: Stewart Bryant <[email-masked]>
Date: Thu, 16 Jan 2003 18:54:12 +0000

I am looking at the congestion section of the arch
revision (we need one). It seems to me that we can divide the
problem up into two traffic classes:

o Traffic known (perhaps by SLA, perhaps by audit) to be TCP
friendly

o Traffic of unknown provenance

In the former case we need do nothing. Natural packet discard
will feed back to the transport layer, and the right things
will happen. I include in this case IP over packet PW, and IP
over ATM PW. I propose that the term "TCP friendly" be left
sufficiently general that it covers any IETF transport (they
are all supposed to be TCP friendly), and other similar
transports such as TP4 (if it still exists).

For the "traffic of unknown provenance", it seems to me that
<draft-ietf-tsvwg-tfrc-05.txt>
could be used to calculate the maximum offered load, and
the PE would then be required to maintain it's load below
this rate (if necessary by shutting down PWs). The
statistics needed to operate this algorithm look a bit
daunting for a forwarding system, but presumably
some stastical view of the counters, a priori knowledge
of the bit rate etc would simplify things.

Has anyone elso looked at this, and does it seem like the
right way to go?

Stewart