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

Yoshifumi Nishida <nishida@sfc.wide.ad.jp> Tue, 02 April 2013 18:09 UTC

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Date: Tue, 02 Apr 2013 11:09:13 -0700
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From: Yoshifumi Nishida <nishida@sfc.wide.ad.jp>
To: Michael Tuexen <Michael.Tuexen@lurchi.franken.de>
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Subject: Re: [tsvwg] WGLC Announcement for draft-ietf-tsvwg-sctp-sack-immediately-02: 19th March 2013
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Hi Michael,

On Tue, Apr 2, 2013 at 12:27 AM, Michael Tuexen
<Michael.Tuexen@lurchi.franken.de> wrote:
> On Apr 2, 2013, at 8:29 AM, Yoshifumi Nishida wrote:

>> 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.

OK. I just wanted to mention that in ideal equilibrium state, we might
need to set I-bit every packet since you'll get an ACK for 1 MSS,
which opens 1 MSS in cwnd.
But, as far as I can think this won't be a problem as the receiver has
a freedom to ignore it if it's necessary. (e.g. too much overhead)

BTW, we might want to set I-bit when we find there's no more packet to
send in buffer after sending a packet, even though
SCTP_SACK_IMMEDIATELY is not used.
Do you have any comment on this?

Thanks,
--
Yoshifumi

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