Subject: [PCN] Adaptive capacity systems

From: Fausto Vieira <[email-masked]>
Date: Tue, 14 Apr 2009 16:45:31 +0100

Dear PCN group,

I recently became aware of this WG and I found it very interesting since
I was previously working in similar topics.
I was trying to check if PCN covered adaptive capacity systems and was
unable to find such reference.
If you search for a paper I wrote named "Adaptive RED for Cross-layer
DVB-S2 systems", you see that I address the problem of adaptive capacity
systems that apply Adaptive Coding and Modulation (ACM) and/or Power
Control to vary the capacity according to the channel conditions.
Basically all advanced wireless systems employ such techniques, in order
to maximize bandwidth and/or limit Packet Error Rate (PER).
I believe that PCN would be a perfect tool for standardizing a solution
for inelastic flows for adaptive capacity systems that have slow
bandwidth variations (slow fading channel impairments). However, from
what I could find out, this is not foreseen and only catastrophic
bandwidth redutions are foreseen.

Looking forward for your comments,

Fausto

-- 
Fausto Vieira, PhD
Instituto de Telecomunicações
Faculdade de Engenharia da Universidade do Porto
Rua Dr. Roberto Frias, s/n 4200-465 Porto PORTUGAL

---

From: <[email-masked]>
Date: Wed, 15 Apr 2009 08:51:43 +0200

Hello Fausto,

it is true, the main focus of the PCN WG up to now seems to be expressing 
a wish for PCN bandwidth reduction by "termination". If you read the drafts, 
you'll find however that what PCN delivers is an indication of a network 
condition (admit, admission stop and termination). At least theoretically, 
PCN does not determine how to reduce bandwidth once "termination" is 
indicated.

I personally dislike the idea of terminating application sessions to reduce 
PCN bandwidth consumption. Negotiating different codecs or changing bandwith 
of an adaptive codec seems a better choice - for personal communication 
services. I however couldn't figure out yet, how to deal with unicast 
streaming, if my wish is to reduce PCN bandwidth consumption by indicating 
this network condition to the application layer.

I do not regard load conditions resulting in "termination" as standard 
operational conditions, these must be an exception no matter how the 
bandwidth consumption is reduced.

Regards,

Rudiger

Deutsche Telekom Netzproduktion GmbH 
Zentrum Technik Einführung 
Technik Internet Backbone, TE142-19
Rüdiger Geib
Heinrich Hertz Str. 3-7
64297 Darmstadt
Tel.: 06151/6282747
Fax: 0251/7985109

Deutsche Telekom Netzproduktion GmbH 
Aufsichtsrat: Timotheus Höttges (Vorsitzender) 
Geschäftsführung: Friedrich Fuß (Vorsitzender), Albert Matheis, Klaus Peren 
Handelsregister: Amtsgericht Bonn HRB 14190 
Sitz der Gesellschaft: Bonn 
USt-IdNr.: DE 814645262

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Fausto Vieira
Sent: Tuesday, April 14, 2009 5:46 PM
To: [email-masked]
Subject: [PCN] Adaptive capacity systems

Dear PCN group,

Fausto

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