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Re: [tcpm] draft-anumita-tcpm-stronger-checksum

<L.Wood@surrey.ac.uk> Thu, 10 June 2010 06:45 UTC

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From: L.Wood@surrey.ac.uk
To: rs@netapp.com
Date: Thu, 10 Jun 2010 07:45:09 +0100
Thread-Topic: [tcpm] draft-anumita-tcpm-stronger-checksum
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Cc: tcpm@ietf.org, ananth@cisco.com, L.Wood@surrey.ac.uk, touch@isi.edu
Subject: Re: [tcpm] draft-anumita-tcpm-stronger-checksum
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On 10 Jun 2010, at 00:53, Scheffenegger, Richard wrote:
> 
> Further, I have spent some time looking for research on the
> effectiveness of SACK - as this option would reduce the typical number
> of SACK fields from a maximum of 3 down to 2. But from what I learned,
> it seems that the number of SACK fields in an ACK have the property of
> diminishing returns. You gain a lot from the 1st field; somewhat from
> the 2nd, a bit from the 3rd, and having a 4th is surplus :).

That's probably because TCP's dupack threshold is three, after which
fast recovery is invoked.

Lloyd Wood
L.Wood@surrey.ac.uk
http://sat-net.com/L.Wood

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