Re: [tsvwg] WGLC Announcement for draft-ietf-tsvwg-sctp-sack-immediately-02: 19th March 2013

[Michael Welzl <[e-mail]>]

Hi,

I have read this draft and support it.

Regarding the issue below:


On 2. apr. 2013, at 09:27, Michael Tuexen wrote:

> On Apr 2, 2013, at 8:29 AM, Yoshifumi Nishida wrote:
> 
>> Hi,
>> 
>> I support this draft.
>> Some minor questions I have are related to the following rule in the draft.
>> "the sending of a DATA chunk fills the congestion or receiver window."
>> 
>> 1: I am personally curious about how much benefit we can get by this.
>>   If there's an analysis on this, I will want to see it in the reference.
> Hi Yoshifumi,
> 
> some simulation results are available at:
> Improving the Acknowledgment Handling of SCTP
> Rüngeler, I.; Tüxen, M.; Rathgeb, E. P.
> Proceedings of the 4th International Conference on Digital Society (ICDS 2010), February 2010.
>> 
>> 2: Because this rule will be checked on every packet transmission, I
>> would like to know if the draft suggests to set I-bit everytime we
>> have a chance or there might be a case where we shouldn't.
> The sender could do it to switch off delayed SACK. However, this
> might not be useful. Therefore, as stated, the sender should set it,
> when he is waiting for an SACK.

Could there be a way to phrase this in that style, to also make it more general than "a DATA chunk fills the congestion or receiver window" ?

I'm thinking about the case that draft-ietf-tcpm-rtorestart-00 addresses, of an application-limited sender that only has one SACK to expect and, in case it doesn't arrive, only a timeout to rely upon. Unless I'm missing some SCTP-specific detail here, it should also be beneficial to SACK early in this case (see fig. 1 in our draft).

This case would be covered by "when it is waiting for a SACK" but not by "fills the congestion or receiver window" (because both of these windows may be much larger than what the sender really transmits).

Cheers,
Michael


> 
> Best regards
> Michael
>> 
>> Thanks,
>> --
>> Yoshifumi
>> 
>> 
>> On Tue, Mar 19, 2013 at 11:49 AM, Gorry Fairhurst <[e-mail]> wrote:
>>> 
>>> This email announces the start of a working group last call for
>>> draft-ietf-tsvwg-sctp-sack-immediately-02.txt, "SACK-IMMEDIATELY Extension
>>> for the Stream Control Transmission Protocol". This document is now thought
>>> to be ready to proceed to be published as a PS. Please send any comments to
>>> the TSVWG list.
>>> 
>>> The draft is available at:
>>> http://datatracker.ietf.org/doc/draft-ietf-tsvwg-sctp-sack-immediately/
>>> 
>>> The last call will run for TWO weeks, ending Friday 5th April 2013.
>>> 
>>> Emails saying "I support" or "I don't support" publication are also most
>>> helpful in judging the WG consensus. Please let us know if this draft is
>>> useful and seems to provide the correct advice.
>>> 
>>> James, David and Gorry
>>> (TSVWG Chairs)
>>> [e-mail]
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>> 
>