Date: Thu, 22 Nov 2001 03:30:48 -0600 (CST) From: Ryan Thompson <ryan@sasknow.com> To: francisv@dagupan.com Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Maximizing throughput Message-ID: <Pine.BSF.4.21.0111220318320.78399-100000@ren.sasknow.com> In-Reply-To: <10F29E27A956D511B0940050DA8D86A9340BE6@apmail.dagupan.com>
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francisv@dagupan.com wrote to freebsd-questions@FreeBSD.ORG: > Hi, > > I have an Intel Pro 100/S NIC on FreeBSD 4.4-STABLE -- > transferring huge (~650MB) files to another computer is only > around 1.78Mbps. The machines are connected via a Cisco 3500XL > switch at full-duplex, 100Mbps. Is there any other way to increase > the throughput or is this the actual bandwidth limit? 1.78Mbps is pretty abysmal for a 100Mbps link. There are a lot of factors which may be causing this. I'm guessing (correctly, I bet) that it is NOT a configuration issue with FreeBSD, unless prior to this, you were messing with network settings that you shouldn't have. :-) So, I don't have an answer for you, but I'll take you through some troubleshooting that will probably get to the root of the problem fairly quickly. For rates that low, packets are almost certainly getting dropped. My first wave of questions goes something like this, 1. What application layer protocol is being used to transfer? 2. Does it run over TCP or UDP? 3. Are you using CAT5 cabling between both hosts and the switch? 4. How loaded are the machines? The switch? 5. How did you calculate your "speed" statistic? Are you sure? 6. Are there any routers between the two hosts? Things to try: Connect the machines directly with crossover cable, or connect them to a hub. Run tcpdump on one of the machines (or another host on the same segment) and look for any weirdness. As for possible causes/remedies, it's hard to say at this point. Like I said, one of your likely symptoms is dropped packets. This could happen at just about any layer. Maybe your cabling is poor grade (or there is too much EMI), causing Ethernet frames to get dropped. Maybe one of the hosts (or the switch) is configured wrong. Maybe your transfer application is broken. Maybe one of your network cards needs to be replaced. Maybe one of your cables is defective. So, as for increasing the bandwidth limit, you'll need to fix whatever is slowing things down. :-) Hope this helps, - Ryan > --- > francis a. vidal [bitstop network services] | http://www.dagupan.com > streaming media + web hosting | http://www.keystone.ph > v(02)330-2871,(02)330-2872; f(02)330-2873 | http://www.kuro.ph > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > -- Ryan Thompson <ryan@sasknow.com> Network Administrator, Accounts SaskNow Technologies - http://www.sasknow.com #106-380 3120 8th St E - Saskatoon, SK - S7H 0W2 Tel: 306-664-3600 Fax: 306-664-1161 Saskatoon Toll-Free: 877-727-5669 (877-SASKNOW) North America To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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