Date: Sun, 30 May 1999 17:17:45 -0700 From: bmah@CA.Sandia.GOV (Bruce A. Mah) To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: dgilbert@velocet.ca (David Gilbert), wollman@khavrinen.lcs.mit.edu, freebsd-net@FreeBSD.ORG Subject: Re: Linux and Solaris tcp beating FreeBSD 4:1 Message-ID: <199905310017.RAA14008@stennis.ca.sandia.gov> In-Reply-To: Your message of "Sun, 30 May 1999 17:59:46 %2B0200." <199905301559.RAA17069@labinfo.iet.unipi.it>
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--==_Exmh_1604981672P Content-Type: text/plain; charset=us-ascii If memory serves me right, Luigi Rizzo wrote: > If you have access to both sides of the adsl link, i think you might > more effectively implement link-level retransmits (i am not sure, but > it might be that ppp already does this). > > It could be a relatively simple project to implement within a > FreeBSD-based router or bridge Some of my former colleagues at UC Berkeley did some rather nifty work (IMHO) in this area. Although originally designed for use with (lossy) wireless LANs, it sounds applicable in this environment: http://www.cs.berkeley.edu/~hari/papers/snoop.html It's designed for the case of TCP segments passing over a lossy link, where you have control of the router/gateway/base station on the far ("upstream") side. "Snoop" is aware of the contents of TCP segments passing through the router, and performs local retransmissions of segments according to some criteria (that I used to remember but can't now). The high-order-bit is that the snoop agent can detect (and initiate) retransmission faster than the normal end-to-end TCP algorithms would. No modification is necessary to the endpoints. They have code for BSD/OS 3.0 and 2.1. Having never looked at the code, it'd be pure speculation on my part to venture an opinion on how portable it is. Hope this helps, Bruce. --==_Exmh_1604981672P Content-Type: application/pgp-signature -----BEGIN PGP MESSAGE----- Version: 2.6.2 iQCVAwUBN1HVKajOOi0j7CY9AQFF+QP/eDF4TubKhrRURpUsmxPgykBtjc2wPYgp xFEOLvpuPAvqVLtQL9oMjkJT406xM8NITg8ZRTIAJUNKRJUIaOWdQR6BDIYuVbFM pPR3sYoS2LngaZ/UF7FlzmMJlPPSSPh7gV9XL5SPOWguzjlMe2WLVEaBaEgN1IX+ sKgf05TYheg= =IgO1 -----END PGP MESSAGE----- --==_Exmh_1604981672P-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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