Date: Sat, 24 Jun 1995 13:07:38 -0400 From: dennis@et.htp.com (dennis) To: freebsd-hackers@freebsd.org Subject: Re: FreeBSD as a router Message-ID: <199506241707.NAA19349@mail.htp.com>
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Tom Samplonius says.... >> That said, be aware that any kind of UN*X box doesn't exactly compete >> with a Cisco in terms of performance. They throw raw hardware at the >> problem whereas we have to do it the hard way, in software. > Cisco doesn't run IP in Hardware...in fact 2 PCI cards should have more hardware pop than a multi-ethernet cisco. > The bottleneck certainly can't be in the CPU can it? Where is the >bottleneck with PCI and a good 486 motherboard? > The bottleneck is in he way that BSD communicates with interfaces. Most ethernet routers "cheat" to get performance. They call it creative things like "fast packet switching", but all they really do is keep all of the local interface addresses cached and bypass standard IP processing when local packets arrive. You could do it in BSD by passing packets directly from one interface to another instead of passing them to IP. We do it in our IPX module for BSD/OS and get very good throughput (haven't finished porting it to FreeBSD yet), but its very usable with 2 SMC 16-bit cards (haven't tried PCI yet) with much greater then 1mbs throughput. To do this for IP would be messy and shouldn't be part of a good operating system. The bottom line is that UN*X boxes aren't really appropriate for more local routers...multiple ethernets on a WAN, yes, but for 4 ethernets there are more appropriate solutions. Dennis
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