Re: Fix for SLOW PPP Bug

rasmus@madhaus.utcs.utoronto.ca
Thu, 11 Apr 1996 16:28:21 -0400 (EDT)

> I think Solaris is just very bad at dealing with large RTTs such as you
> get over a 14.4k PPP link. It doesn't wait long enough for the ACK,
> and resends the packet. This affects more than just Linux.

I saw this when I upgraded a server from Solaris 2.4 to 2.5. Suddenly
both Linux and Win95 PPP clients showed dramatic PPP slowdowns. Tossing
tcpdump at it revealed that Solaris 2.5 tries to do MTU Path Discovery
and that fiddling with the Solaris kernel-level settings improved the
situation. Window sizes seemed out of whack and the Solaris end would
re-transmit packets wildly.

--
Rasmus Lerdorf
rasmus@madhaus.utcs.utoronto.ca