RE: WG last call: draft-ietf-tewg-diff-te-reqts-04.txt

[Jim Boyle <jboyle@pdnets.com>]

At a higher level, in essence you are stating that we should change our
tact from:

	o) we agree that there needs to be at least one common
	   bandwidth contraint model across implementations.  Technical
	   proposals need one specified andrequired for implementation

to adding:

	o) a few of us have looked into something called maximum
	   allocation and think it's better than russian dolls.

I don't think the requirements document is the place to resolve what the
default model should be.  Are you saying that there shouldn't be a default
model - or just that you have a difference of opinion on what the default
should be?

If the former - then please suggest revised text for the paragraph you
quoted.  If it is the latter - then I think that is another thread for the
list against the protocol draft.

Jim


On Thu, 30 May 2002, Lai, Wai S (Waisum), ALASO wrote:

> As stated in page 9 of the draft:
>    "At the time of writing this document, it is not clear whether a
>    single model of Bandwidth Constraints is sufficient, which one it
>    should be and how flexible this model really needs to be and what
>    are the implications on the DS-TE technical solution and its
>    implementations. The DS-TE technical solution must specify one
>    default bandwidth constraint model which must be supported by any
>    DS-TE implementation."
>
> We have now completed a study to investigate the performance of the
> different Bandwidth Constraints models.  We will document in details
> our findings in a forthcoming draft.
>
> We propose that the following highlights be included in the DS-TE
> Requirements draft to provide guidance to protocol development.
> One place to put the text is perhaps at the end of Section 3.3:
>
> "Work is in progress [reference of the draft to be provided] to
> investigate the performance of the different Bandwidth Constraints
> models.  Preliminary results indicate that in comparison to the
> maximum allocation model above (first example), the Russian Doll
> model:
> a) permits a greater degree of bandwidth sharing among different
> traffic classes and hence gives better performance under normal
> conditions than other Bandwidth Constraints models,
> b) under overload, such sharing leads to a tighter coupling
> between various classes and is not able to provide robust service
> protection/isolation, and
> c) is not well-suited to a CAC/blocking operational mode when
> preemption is disabled.
> Such analysis should be used to provide guidance to DS-TE protocol
> development.  Furthermore, a model more like the maximum allocation
> model may be more appropriate as a default model because of the
> observed behavior."
>
> Thanks, Wai Sum.
>
> -----Original Message-----
> From: Jim Boyle [mailto:jboyle@pdnets.com]
> Sent: Sunday, May 19, 2002 10:04 PM
> To: te-wg@ops.ietf.org
> Subject: WG last call: draft-ietf-tewg-diff-te-reqts-04.txt
>
>
>
> This message begins a WG last call for the following:
>
> 	draft-ietf-tewg-diff-te-reqts-04.txt
>
> This WG document addresses a WG milestone.  It is proposed as an
> Informational RFC.  WG last call ends May 31, 2002.
>
>
>
>