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Hi Naotaka,

On Fri, 07 Nov 2003 09:36:44 +0900
"MORITA, Naotaka" <morita.naotaka@lab.ntt.co.jp> wrote:

> I would like to draw QoS experts attention to the following three documents.
> 
> http://www.ietf.org/internet-drafts/draft-morita-tsvwg-pps-01.txt
> http://www.ietf.org/internet-drafts/draft-morita-tsvwg-mfphb-00.txt
> http://www.ietf.org/internet-drafts/draft-morita-tsvwg-mfverify-00.txt
> 
> I am going to make a presentation on Monday morning at TSV WG.

After reading draft-morita-tsvwg-mfphb-00.txt and attending your
presentation, I have some remarks related to this approach:
- I'm not quite sure whether this is really a PHB definition.
  It seems to me, that it is actually a mix of
  * a scheme for measured-based admission control and resource provisioning
  * a Per-Domain Behavior (see RFC 3086)
  * a PHB group description

- The scheme inherently relies on feedback information and it should be made
  clear how the feedback can be provided (you mentioned RTCP as an example,
  what about others?).

- Instead of defining a new PHB, possibly two Class Selector PHBs
  or even an AF class can be used ("green" packets get high priority after
  admission control, "yellow" and "red" packet may be used for probing).
  AF usually gives no guarantees for delay and jitter, however, if AF is
  provisioned properly, "green" packets may get some guarantee.

- For security and robustness, it is essential to police the markings
  for the higher priority. Otherwise the service guarantees for other users
  are violated by a malicious or ill-behaving end-system. Therefore, I think
  first-hop routers should do the policing (based on the feedback
  information?).

- I see some value in the overall approach, but IMHO the proposal may 
  be turned into a description for a measurement-based
  admission control scheme and PDB using Class Selector PHBs.

I copied to the relevant lists (diffserv-interest and tsvwg) as I'm 
interested in other opinions.

Best regards,
 Roland

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[Diffserv-interest] Re: [NSIS] PPS and MF-PHB