[103560] in North American Network Operators' Group
Re: "Does TCP Need an Overhaul?" (internetevolution, via slashdot)
daemon@ATHENA.MIT.EDU (Sam Stickland)
Mon Apr 7 06:45:50 2008
Date: Mon, 07 Apr 2008 11:29:05 +0100
From: Sam Stickland <sam_mailinglists@spacething.org>
To: Kevin Day <toasty@dragondata.com>
CC: Paul Vixie <paul@vix.com>, nanog@merit.edu
In-Reply-To: <B9FE54C9-6356-414D-9FCE-9A124208DB9C@dragondata.com>
Errors-To: owner-nanog@merit.edu
Kevin Day wrote:
> Yeah, I guess the point I was trying to make is that once you throw
> SACK into the equation you lose the assumption that if you drop TCP
> packets, TCP slows down. Before New Reno, fast-retransmit and SACK
> this was true and very easy to model. Now you can drop a considerable
> number of packets and TCP doesn't slow down very much, if at all. If
> you're worried about data that your clients are downloading you're
> either throwing away data from the server (which is wasting bandwidth
> getting all the way to you) or throwing away your clients' ACKs. Lost
> ACKs do almost nothing to slow down TCP unless you've thrown them
> *all* away.
If this was true surely it would mean that drop models such WRED/RED are
becoming useless?
Sam
