At 17:43 -0500 11/10/97, Chuck Nunez wrote:
>that's already been solved. Adjusting the window size to compensate for
>the BANDWIDTH*DELAY PRODUCT the ultimate solution. The problem seems to be
>how to get it done on any particular platform. Your comment about the
>"setsockopt" is the key.
...
>
>Selective acknowledgements would be helpful, but I agree not essential.
>
I disagree somewhat with these statements. Getting the window size correct
is clearly necessary, but IMHO not sufficient for good performance. The
large RTT creates a long feedback loop (which requires the large window);
that means that the normal TCP responses to packet loss (either congestion
or corruption) will be slowed down on the satellite link, resulting in
degraded performance. This is a place where SACK should help.
There are also various issues of applications design (e.g. HTTP 1.1 without
pipelining will be really awful on a sat link); these may be outside the
scope of this group?
A question regrarding your comments on retransmit timers: Do these timers
not adjust with the measured RTT? Or are these maximum timer values?
Hans Kruse, Associate Professor
McClure School of Communication Systems Management, Ohio University
9 S. College Street
Athens, OH 45701
614-593-4891 voice, 614-593-4889 fax, [email protected]
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