Date: Fri, 11 May 2007 10:22:43 +0500 From: <suvashrestha@wlink.com.np> To: freebsd-net@freebsd.org Subject: bridge query Message-ID: <SCEtVlql.1178860963.0544890.suvashrestha@wlink.com.np> In-Reply-To: <mailman.6487.1178613103.783.freebsd-net@freebsd.org>
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Hello.... I am using TCP sockets to measure packet transfer. And I am also not looking to optimise the link. I just want to know if this is the usual behaviour of the freeBSD TCP or bridge when we apply delay and packet loss. The throughtput falls from around 8 Mbps (8000 Kbps) to just 80 Kbps. This is very significant. Thanks suva How are you measuring packet transfer (single TCP socket, multiple TCP sockets or UDP) and what were you expecting? For a TCP connection, the window size needs to be able to handle at least 1 RTT (0.5 second in this case) of data. This translates to a total of 5Mb (~640KB) outstanding data to get 10Mbps throughput. With only a single cnnection, you would need a 640KB window size - which is far larger (an order of magnitude or so) than typical. TCP is also designed to work on a mostly lossless link. I am not sure how much a 5% packet loss will affect it but I would expect it to be significant. I'm not sure how to optimise throughput in this situation. Peter Jeremy
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