Date: Sun, 16 Mar 2003 12:47:40 -0500 From: Bill Moran <wmoran@potentialtech.com> To: Olivier Dony <odony@student.info.ucl.ac.be> Cc: Simon Barner <barner@in.tum.de>, freebsd-questions@freebsd.org Subject: Re: Too many collisions on network? Message-ID: <3E74B8BC.4030009@potentialtech.com> In-Reply-To: <002201c2ebd3$92d0a7d0$1502a8c0@blacktrap.net> References: <005d01c2ebcb$82b343b0$1502a8c0@blacktrap.net> <20030316152335.GA1434@zi025.glhnet.mhn.de> <002201c2ebd3$92d0a7d0$1502a8c0@blacktrap.net>
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Olivier Dony wrote: > On Sunday, 16 March, 2003 16:23, Simon Barner wrote: > >>Are you running your network adaptor in full-duplex mode? Perhaps the device on >>the other end of the wire does only support half-duplex. Changing this increased >>the throughput from 20kb/s to almost 1mb/s on our internal network here >>(10baseT/UTP). > > > I'm not really sure about this, here is the output of ifconfig related > to the external interface : > > root@charon:/root# ifconfig -m fxp0 > fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > inet xxx.xxx.191.100 netmask 0xfffffff0 broadcast xxx.xxx.191.111 > inet xxx.xxx.191.101 netmask 0xffffffff broadcast xxx.xxx.191.101 > ether 00:e0:81:23:c5:32 > media: Ethernet autoselect (10baseT/UTP) > status: active > supported media: > media autoselect > media 100baseTX mediaopt full-duplex > media 100baseTX > media 10baseT/UTP mediaopt full-duplex > media 10baseT/UTP > media 100baseTX mediaopt hw-loopback > > It seems that fxp(4) supports full-duplex but that it is currently > disabled, and I guess this is because the other end of the wire doesn't > support it, since the media has been autoselected? Please correct me > as I have never played a lot with ifconfig except for basic configutarion. > I wouldn't be too eager to do tests with this setting since this is a > production server and I have no direct physical access to it, so shutting > down the only interface by mistake is *not* an option ;-) > But if I was to change it, how would I go about this without shutting down > fxp0? 'ifconfig fxp0 media 10baseT/UTP mediaopt full-duplex' ?? I have seen cases where the media type was auto-negiotiated wrong. I think this was due to crappy wiring, but the circumstances didn't allow for a lot of experimenting. I would suggest talking to your ISP and verifying what the connection _should_ be. Then work towards getting it there. When the two ends see something different, performance blows. Going to full-duplex should reduce collisions to 0, and give you the max performance available. I just did some experimenting with turning duplex from half to full and back on my computer here, and if there's any interruption, it was less than I could easily measure. Don't know if that'll be the same with all switches or not. -- Bill Moran Potential Technologies http://www.potentialtech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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