nanog mailing list archives
Re: Linux Router: TCP slow, UDP fast
From: Mathias Wolkert <mathias.wolkert () gmail com>
Date: Sun, 15 Feb 2009 11:10:44 +0100
I would turn off ethernet flow control. Maybe you already have.It can be really mean on tcp's own flow control if the switch has an issue of some kind (load).
/Tias 15 feb 2009 kl. 10.24 skrev Chris <chris () ghostbusters co uk>:
Thanks, Karl, Allen and Nickola.I failed-over to another router last night and briefly had full expected throughput but this morning despite dropping providers and moving between routers again for trial and error I still see _outbound_ TCP at about thesame 300 - 600kbps per session. I eliminated conntract modules firstly, then iptables as a whole. I'veeliminated TSO and checksumming (which caused very sticky connections) onthe e1000 NIC. The failover router has a slightly older kernel and was working before Christmas so it's not most likely not kernel versions. I've also triedremoving FIB_TRIE as a stab in the dark with no success. And the failoverrouter connects using FE not GE so I've eliminated NICs and connection speeds to a front-facing switch.The only constant is the front-facing switch (it's negotiating perfectly atFD though) so all I can think of is removing that from the equation.It's definitely only _outbound_ TCP getting buffered though ! I've pushed92Mbps on a FE link with UDP and uploaded at 16Mbps on a 16Mbps link.Any last ideas appreciated before causing headaches removing switches wouldbe appreciated. Thanks, Chris
Current thread:
- Re: Linux Router: TCP slow, UDP fast, (continued)
- Re: Linux Router: TCP slow, UDP fast Chris (Feb 14)
- Re: Linux Router: TCP slow, UDP fast Chris (Feb 14)
- Re: Linux Router: TCP slow, UDP fast Mikael Abrahamsson (Feb 14)
- Re: Linux Router: TCP slow, UDP fast Florian Weimer (Feb 14)
- Message not available
- Re: Linux Router: TCP slow, UDP fast Chris (Feb 14)
- Re: Linux Router: TCP slow, UDP fast Chris (Feb 14)
- Re: Linux Router: TCP slow, UDP fast Allen Smith (Feb 14)
- Message not available
- Re: Linux Router: TCP slow, UDP fast Chris (Feb 15)
- Message not available
- Re: Linux Router: TCP slow, UDP fast Chris (Feb 15)
- Re: Linux Router: TCP slow, UDP fast Geert Bosch (Feb 15)