Subject: RE: [Tsvwg] Accepting draft-baker-tsvwg-admitted-voice-dscp as WG item

From: "Jozef Babiarz" <[email-masked]>
Date: Wed, 6 Dec 2006 18:58:14 -0500

On the issue of one DSCP per queue or two or more DSCPs mapped into a
queue. 
My view is that both are possible depending on capability of scheduler
in the router.

With one queue approach, policing per DSCP or through other policing
policies on edge and interior routers is needed. 
One example is that both EF-Admit and normal EF traffic is policed
independently and should it exceed its configured level will be dropped.

On other option is to police normal EF to rate R1 and sum of EF-Admit
and normal EF to rate R2 where R2 is > R1. If R1 is exceeded drop normal
EF traffic that exceeds R1. If R2 is exceeded drop any EF packet above
R2. 
There are other possible configuration that operator may wish to use,
depending on the service they wish to provide.

The two queue approach requires a hieratical scheduler that can rate
limit fairly traffic in each priority scheduled queue, as well each
priority queue needs to support starvation avoidance of other queues.
Through different configuration of the scheduler similar behavior can be
provided.

The single queue with per DSCP policers is an approach that many current
routers can support.

Regards, Joe
-----Original Message-----
From: Janet P Gunn [mailto:[email-masked]] 
Sent: Wednesday, November 29, 2006 12:07 AM
To: Magnus Westerlund; tsvwg
Subject: RE: [Tsvwg] Accepting draft-baker-tsvwg-admitted-voice-dscp as
WG item

I also support this draft becoming a WG item.

If possible, I would like to see a bit more discussion of the pros and
cons
of "Two DSCPs, Two Queues" vs. "Two DSCPs, One Queue".  In particular I
would like to see a discussion of the relative policing of the EF and
EF-Admit traffic in the "Two DSCPs, One Queue" case.  I ask this because
I
have seen some analysis suggesting that the policing on the EF traffic
could/would be "loose" enough that both EF and EF-Admit traffic would
experience significant dropping when EF traffic experiences a prolonged
"overload".

Also, section 2.2  describes five major ways that capacity admission can
be
done.

The document states that the first two listed (2.2.1 "By Assumption" and
2.2.2 "By Call Counting") only qualify for "EF", not  "EF-Admit".
 But it is not clear whether the other 3  (2.2.3   "End-point capacity
admission performed by probing the network", 2.2.4  "Centralized
capacity
admission control", and 2.2.5  "Distributed capacity admission control")
qualify for "EF-Admit" or not.

Janet

> -----Original Message-----
> From: Magnus Westerlund [mailto:[email-masked]]
> Sent: Wednesday, November 22, 2006 7:34 AM
> To: tsvwg
> Subject: [Tsvwg] Accepting draft-baker-tsvwg-admitted-voice-dscp as WG
> item
>
> This is a call for input on accepting An EF DSCP for Capacity-Admitted
> Traffic (draft-baker-tsvwg-admitted-voice-dscp) as WG item. Please
> provide any input both positive and negative at the latest on
Wednesday
> the 6th of December.
>
> Cheers
>
> Magnus Westerlund
>
> IETF Transport Area Director & TSVWG Chair
> ----------------------------------------------------------------------
> Multimedia Technologies, Ericsson Research EAB/TVA/A
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> Ericsson AB                | Phone +46 8 4048287
> Torshamsgatan 23           | Fax   +46 8 7575550
> S-164 80 Stockholm, Sweden | mailto: [email-masked]
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>