David Miller wrote:
From: Rick Jones <[EMAIL PROTECTED]>
Date: Thu, 30 Aug 2007 17:09:04 -0700 (PDT)
Enable configuration of the minimum TCP Retransmission Timeout via
a new sysctl "tcp_rto_min" to help those who's networks (eg cellular)
have quite variable RTTs avoid spurrious RTOs.
Signed-off-by: Rick Jones <[EMAIL PROTECTED]>
Signed-off-by: Lamont Jones <[EMAIL PROTECTED]>
Thanks for doing this work Rick.
But as John Heffner and I both mentioned, it's pretty clear we should
do this as a routing metric. Both for handling realistic scenerios
where the sysctl doesn't work, and to help prevent misuse (example:
someone decides that it would be _totally_ _awesome_ for "Carrier
Grade Linux" to set this to 3 seconds by default in /etc/sysctl.conf
and crap like that).
If nothing else it was worth the practice :) I'll be happy with either
mechanism, just wasn't sure if the jury was still out on whether making
it a routing metric was really necessary. I can see where it would be
goodness if one had separate paths out of a system, one with the highly
variable RTT and one with non-trivial loss rates, just that thusfar I've
not come across any :) I've only seen one path with high RTT
variability and the other path with trivial loss rates.
Also, not surprisingly, the folks for whom I'm doing this are a triffle
"anxious" so I figured that simplicity was worthwhile. Particularly if
it was going to be the case those folks were going to be asking for
back-ports.
Anyhow, I'll try grubbing around the source code (already doing that to
see about writing a pet tcp cong module) but if pointers to the likely
relevant files were available I could try to help thrash-out the routing
metric version. Like I said the consumers of this are a triffle well,
"anxious" :)
rick
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