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Re: [tcpm] question regarding draft-gomez-tcpm-delack-suppr-reqs

Carles Gomez Montenegro <carlesgo@entel.upc.edu> Sat, 02 May 2020 08:34 UTC

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Date: Sat, 02 May 2020 10:34:15 +0200
From: Carles Gomez Montenegro <carlesgo@entel.upc.edu>
To: Yuchung Cheng <ycheng@google.com>
Cc: jon.crowcroft@cl.cam.ac.uk, "tcpm@ietf.org Extensions" <tcpm@ietf.org>, Neal Cardwell <ncardwell@google.com>
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Subject: Re: [tcpm] question regarding draft-gomez-tcpm-delack-suppr-reqs
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Hi Yuchung,

<snip>

>> Note that the problem pointed out is that, as stated in the RFC 5681
>> text
>> above:
>>
>>    "During slow start, a TCP increments cwnd by at most SMSS bytes for
>>     each ACK received that cumulatively acknowledges new data"
>>
>> It may be desirable to support, during slow start, a cwnd increase by
>> more
>> than SMSS per each ACK acknowledging new data.
> I agree. We in fact implemented Linux to increase cwnd by the exact
> amount sequence (in unit of packets) so slow-start increase function is
> regardless of ack-thinning effect but purely based on amount
> delivered. This has an important effect on
> Wireless as the other ack talk mentions. It also helps in case of ACK
> losses or reordering.

Agreed!

By the way, in the next draft update, we will add that, despite its
"Experimental" status, ABC is supported in many implementations.

<snip>

Thanks,

Carles

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