Date: Sat, 21 Aug 2004 13:18:51 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: "R. W." <list-freebsd-2004@morbius.sent.com> Cc: freebsd-questions@freebsd.org Subject: Re: Equitable Sharing between TCP Sockets Message-ID: <20040821181851.GA18053@dan.emsphone.com> In-Reply-To: <200408211348.29086.list-freebsd-2004@morbius.sent.com> References: <200408211348.29086.list-freebsd-2004@morbius.sent.com>
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In the last episode (Aug 21), R. W. said: > I'm using 5.21 on a desktop computer with a dial-up modem. I tend to > have several applications simultaneously sharing the connection, and > I'm finding that this aspect isn't working as well as it does under > windows 98. > > Under windows each tcp socket would tend to receive at about the same > rate, and intermittent, interactive applications would quickly gain > their fair share. Under FreeBSD a couple of sockets at a time tend to > hog most of the bandwidth, and interactive applications get frozen > out. I don't know what Windows is doing right, but I'm guessing it > has some kind collective management of tcp window sizes, probably > tied-in with the slow-start algorithm. It's more likely that Windows 98's 8k TCP window size is the main factor. FreeBSD defaults to 32768 which is way too high for a modem. 5.2.1 does have a dynamic window-scaling algorithm to improve latency, but it only applies to outgoing streams. Try putting these in /etc/sysctl.conf and see if they help: net.inet.tcp.rcvspace=8192 net.inet.tcp.sendspace=8192 -- Dan Nelson dnelson@allantgroup.com
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