Subject: [Diffserv] A question on Virual Wire (VW) PDB

From: demir <[email-masked]>
Date: Sun, 18 Feb 2001 07:33:25 -0800 (PST)

While traffic is flowing on a node performing EF PHB, is there a suggested
drop mechanisms (i.e. tail drop, random drop) to drop the packets causing
(very) short-term congestion due to worst-case traffic bursts
arriving for VW PDB? /Or this is not a problem at all? /Or It is the
responsibility of EF PHB to attack such a problem if it is a problem?

Alper K. Demir

_______________________________________________
diffserv mailing list
[email-masked]
http://www1.ietf.org/mailman/listinfo/diffserv
Archive: http://www2.ietf.org/mail-archive/working-groups/diffserv/current/maillist.html

---

From: Kathleen Nichols <[email-masked]>
Date: Tue, 20 Feb 2001 10:05:14 -0800

Perhaps it is not clear from the rough drafts we have written so far
on the VW PDB, but there are statements in RFC 2598 (which we referred
to)
in its Section 1 that state the very strict assumptions that prohibit
this.
Further, there was some additional work in the VW PDB draft on
conditions
for this. 

The only potential place for dropping in a correctly configured VW PDB,
might be at the edge if a flow was being shaped and the flow exceeded
the shaping rate for long enough to overflow its buffer. No
recommendation
is made on the queue management scheme since 1) this is an undesirable
condition and under some circumstances probably means misconfiguration
and
thus should generate an error and 2) this would depend on the traffic
type.

	Kathie Nichols