TCP Congestion Window Bug?

From: Mark Reginald James (mrj@bigpond.net.au)
Date: Sun Mar 04 2001 - 00:39:46 EST


Hi:

TCP only sends a packet if:

         tcp_packets_in_flight(tp) < tp->snd_cwnd

         (function tcp_snd_test in include/net/tcp.h)

but regards transmission as application-limited if

         tp->packets_out < tp->snd_cwnd

         (function tcp_cwnd_validate in include/net/tcp.h)

So the kernel _always_ thinks the connection is
application-limited, forcing many un-necessary
reductions in the size of the congestion window.

I think the condition in tcp_snd_test should be:

         tcp_packets_in_flight(tp) <= tp->snd_cwnd

Mark

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