Date: Sun, 30 May 1999 23:13:48 -0400 (EDT) From: David Gilbert <dgilbert@velocet.ca> 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: <14161.65132.912907.525115@trooper.velocet.ca> In-Reply-To: <199905301559.RAA17069@labinfo.iet.unipi.it> References: <14161.30204.750053.989577@trooper.velocet.ca> <199905301559.RAA17069@labinfo.iet.unipi.it>
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>>>>> "Luigi" == Luigi Rizzo <luigi@labinfo.iet.unipi.it> writes: >> Fast retransmit is an something that reacts in less than a second? Luigi> it reacts at the third duplicate ack, meaning 3 good packets Luigi> after a loss. If you manage to have st least 4-5 pkts in flight Luigi> you have a chance to trigger fast restransmit. Furthermore Luigi> short packets in your case might reduce the pkt loss rate (for Luigi> a given BER). Luigi> In your case all standard TCP mechanisms will help very little, Luigi> because they are end-2-end and furthermore they assume Luigi> congestion-related loss, not noise-related loss. I tried using a -mtu on the route in question of 500 and 100. 100 was very slow. 500 was about the same as the default. Luigi> If you have access to both sides of the adsl link, i think you Luigi> might more effectively implement link-level retransmits (i am Luigi> not sure, but it might be that ppp already does this). Luigi> It could be a relatively simple project to implement within a Luigi> FreeBSD-based router or bridge Unfortunately, I don't have access to the link layer. The routers are ascend --- but I do have control of both ends. Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://www.velocet.net/~dgilbert | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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