Re: Missing ACKs with Linux 2.2/2.4?

From: Ben Mansell (ben@zeus.com)
Date: Fri Nov 10 2000 - 05:13:21 EST


On Thu, 9 Nov 2000, David S. Miller wrote:

> Any ideas whats going on? I'm no expert at reading tcpdumps, if
> anyone can shed some light on the problem, I'd be most greatful.
>
> Anything less than ~2.2.16 are about as buggy as they come wrt. TCP
> Please upgrade ;-)

A fair point! But I still can't see what the server is doing wrong,
which makes it look like the clients (inc 2.4.0-test10) are misbehaving.

> Something is wrong with the Cobalt side, for sure:
>
> 10:10:15.845869 cobalt-box.echo > hydra.3700: . ack 8681 win 30408 <nop,nop,timestamp 15607469 268081752> (DF)
>
> Cobalt sends the ACK, everything is fine.
>
> 10:10:18.836367 cobalt-box.echo > hydra.3700: P 1:1449(1448) ack 8681 win 31856 <nop,nop,timestamp 15607768 268081752> (DF)
>
> Cobalt then waits for 3 seconds to send data bytes 1:1449
> (ie. the echo service response).

This is a resend of the data sent on line 8 of the trace:

10:10:15.845002 cobalt-box.echo > hydra.3700: P 1:1449(1448) ack 1449 win 31856 <nop,nop,timestamp 0 268081751> (DF)

It looks like hydra didn't ACK this data, so the server eventually
re-sent it?

Ben

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