From: Ben Greear <greearb@candelatech.com>
To: "'netdev@oss.sgi.com'" <netdev@oss.sgi.com>
Subject: Long-term TCP connections suffer on high-latency links.
Date: Thu, 29 Jul 2004 22:01:50 -0700 [thread overview]
Message-ID: <4109D63E.5070006@candelatech.com> (raw)
I have been running a TCP connection over a link with 2 seconds round-trip-time.
It started off well, about 16Mbps in both directions (cwnd trained up to 2100
after a few seconds).
After several hours of running, it is now doing only about 2.2Mbps in one
direction, and 3.4Mbps in the other direction. I have watched the cwnd slowly
increasing by one every 2-5 seconds (it is at 440 on one side and 655 on the
other as I type).
Occasionally, the cwnd drops in half or maybe even goes to zero.
The un-acked packets is always == snd_cwnd.
My suspicion is that for connections needing a cwnd of 2000 or so,
the cwnd does not grow nearly fast enough after the connection
has been established for a while. My naive suggestion would be to
increase cwnd by a certain percentage instead of a fixed number (1).
But, TCP has been around a long while, and surely other people
have noticed things like this, so what am I missing?
Ben
--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
next reply other threads:[~2004-07-30 5:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-30 5:01 Ben Greear [this message]
2004-07-30 5:28 ` Long-term TCP connections suffer on high-latency links Cheng Jin
2004-07-30 6:25 ` Ben Greear
2004-07-30 7:34 ` Baruch Even
2004-07-30 16:16 ` Stephen Hemminger
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4109D63E.5070006@candelatech.com \
--to=greearb@candelatech.com \
--cc=netdev@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).