Subject: RE: [Diffserv] Part 2: FWD: response to comments todraft-charny-ef-definition-00

From: "Kent Benson" <[email-masked]>
Date: Wed, 26 Jul 2000 15:09:38 -0500

Brijesh,

A clarification or consensus on the "any time interval" phrase would be a
good start to clearing everything up.

The goal of this draft was to bring the EF definition in line with what
people thought EF required.  Since people are building boxes that comply
with what they think EF requires the hope was that these implementations
would be compliant with the new definition.  Unfortunately it appears there
may be more than one "intuitive" understanding of EF.  This would complicate
matters.  This seems like a good time to discuss what everyone thinks EF
does and does not require.

Kent

>-----Original Message-----
>From: [email-masked] [mailto:[email-masked]]On Behalf
>Of [email-masked]
>Sent: Wednesday, July 26, 2000 1:02 PM
>To: [email-masked]; [email-masked]
>Cc: [email-masked]; [email-masked]; [email-masked]
>Subject: RE: [Diffserv] Part 2: FWD: response to comments
>todraft-charny-ef-definition-00
>
>
>
>> -----Original Message-----
>> From: [email-masked]
>> [mailto:[email-masked]]On Behalf
>> Of Brian E Carpenter
>> Shahram Davari wrote:
>
>> > So when somebody says they have implemented EF without
>> difficulty, what they
>> > mean is that they are using PQ.
>>
>> Maybe. Let's hear from them. I know of people who are running
>> CBWFQ in support
>> of EF.
>
>I don't think it is such a insurmountable problem.
>
>Yes, there is a problem in the definition of EF PHB draft which means
>that none of the implementations may "precisely" fulfill the
>definition as written in the draft. Assume, if the original draft was
>written with added clarification so that there was no ambiguity about
>"any time interval" in the statement - "you SHOULD get at least the
>configured rate over any time interval greater than MTU/R (R is the
>configured rate)" and also there was added condition that this is only
>true when EF aggregate arrival rate exceeds the configured rate. I
>wonder if this would have made any difference to how most vendors have
>implemented this PHB in their boxes? Let us see the answers from
>people who are proposing the new draft. Please don't give complex
>mathematical derivations (as most have already admitted the problems
>in the basic draft) - just give us plain text explanation that will
>differentiate implementations in two cases.
>
>
>Cheers,
>
>--brijesh
>Ennovate Networks Inc..
>
>
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From: "Brijesh Kumar" <[email-masked]>
Date: Wed, 26 Jul 2000 16:54:15 -0400

Hi Kent,

You are right.

My guess is a new draft is required that:

1) Identifies the problems briefly with the current EF definition (I
don't think a very lengthy explanation is required.). There is a broad
consensus that the current EF condition cannot be fulfilled as
"written" in the draft.

2) Fix the existing definition by removing the term "any time
interval" which is causing all the problems and instead define the
time interval as discussed earlier on this list. Basically, aim to fix
the existing text with minimal changes rather than offer a full new
definition for EF PHB (as done in the current draft).

Cheers,

--brijesh
Ennovate Networks Inc.

> From: Kent Benson [mailto:[email-masked]]
> Sent: Wednesday, July 26, 2000 4:10 PM
> To: [email-masked]
> Cc: [email-masked]