[111868] in North American Network Operators' Group
Re: Linux Router: TCP slow, UDP fast
daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Sat Feb 14 12:58:07 2009
Date: Sat, 14 Feb 2009 18:57:33 +0100 (CET)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Chris <chris@ghostbusters.co.uk>
In-Reply-To: <c8a7026b0902140942l540b1693te2093872c180d4a7@mail.gmail.com>
Cc: nanog list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On Sat, 14 Feb 2009, Chris wrote:
> The RTTs vary massively because the router is forwarding from websites
> on the LAN to visitors worldwide. Is that what you meant ?
And your TCP speed when doing testing is always 300-600 kilobyte/s
regardless of RTT between the boxes with which you're testing?
Without TCP window scaling turned on on the boxes doing TCP with each
others, you're always limited to 1/RTT*64k bytes/s of transfer speed.
Changing window scaling on the linux router will of course not change the
behaviour of the traffic going thru it, only TCP sessions that itself
does.
--
Mikael Abrahamsson email: swmike@swm.pp.se
