nanog mailing list archives
RE: Shady areas of TCP window autotuning?
From: "Frank Bulk - iName.com" <frnkblk () iname com>
Date: Mon, 16 Mar 2009 22:48:42 -0500
It was my understanding that (most) cable modems are L2 devices -- how it is that they have a buffer, other than what the network processor needs to switch it? Frank -----Original Message----- From: Leo Bicknell [mailto:bicknell () ufp org] Sent: Monday, March 16, 2009 9:10 AM To: nanog () nanog org Subject: Re: Shady areas of TCP window autotuning? <snip> What appears to happen is vendors don't auto-size queues. Something like a cable or DSL modem may be designed for a maximum speed of 10Mbps, and the vendor sizes the queue appropriately. The service provider then deploys the device at 2.5Mbps, which means roughly (as it can be more complex) the queue should be 1/4th the size. However the software doesn't auto-size the buffer to the link speed, and the operator doesn't adjust the buffer size in their config. <snip> My wish is for the vendors to step up. I would love to be able to configure my router/cable modem/dsl box with "queue-size 50ms" and have it compute, for the current link speed, 50ms of buffer. Sure, I can do that by hand and turn it into "queue 20 packets", but that is very manual and must be done for every different link speed (at least, at slower speeds). Operators don't adjust because it is too much work. <snip> -- Leo Bicknell - bicknell () ufp org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/
Current thread:
- Shady areas of TCP window autotuning? Marian Ďurkovič (Mar 16)
- Re: Shady areas of TCP window autotuning? David Andersen (Mar 16)
- Re: Shady areas of TCP window autotuning? Leo Bicknell (Mar 16)
- Re: Shady areas of TCP window autotuning? Wayne E. Bouchard (Mar 16)
- Re: Shady areas of TCP window autotuning? Lars Eggert (Mar 16)
- RE: Shady areas of TCP window autotuning? Frank Bulk - iName.com (Mar 16)
- Re: Shady areas of TCP window autotuning? Brett Frankenberger (Mar 17)
- Re: Shady areas of TCP window autotuning? Mikael Abrahamsson (Mar 17)
- Re: Shady areas of TCP window autotuning? Leo Bicknell (Mar 17)
- Re: Shady areas of TCP window autotuning? Marian Ďurkovič (Mar 18)
- Re: Shady areas of TCP window autotuning? Leo Bicknell (Mar 18)
- Re: Shady areas of TCP window autotuning? Marian Ďurkovič (Mar 17)
- Re: Shady areas of TCP window autotuning? Joe Maimon (Mar 17)
- Re: Shady areas of TCP window autotuning? John Schnizlein (Mar 17)
- Re: Shady areas of TCP window autotuning? Tony Finch (Mar 17)
- Re: Shady areas of TCP window autotuning? Lars Eggert (Mar 17)