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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mel.connect.com.au!munnari.OZ.AU!news.ecn.uoknor.edu!paladin.american.edu!gatech!news-feed-1.peachnet.edu!paperboy.wellfleet.com!news3.near.net!sol.caps.maine.edu!web.ddp.state.me.us!gatekeeper.ddp.state.me.us!isdmill From: isdmill@gatekeeper.ddp.state.me.us (David Miller) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: FreeBSD router, as good as a harware router ? Date: 18 Jan 1996 17:24:45 GMT Organization: Maine State Government Lines: 30 Message-ID: <4dlvot$nie@web.ddp.state.me.us> References: <4cof7j$59@news.mistral.co.uk> <4cpu39$sft@uriah.heep.sax.de> <k8d98kgn9t.fsf@slbh03.bln.sel.alcatel.de> <4djtj1$d6u@uriah.heep.sax.de> NNTP-Posting-Host: gatekeeper.ddp.state.me.us X-Newsreader: TIN [version 1.2 PL2] J Wunsch (j@uriah.heep.sax.de) wrote: : blume_h@slbh03.bln.sel.alcatel.de (H. Blume von Contributed) writes: : > interestingly, ANS seems to use IBM RS6000 with some gated as routers : > for two to three 45Mbps plus FDDI interfaces. : This ain't the question. The problem is, hardware routers start : analyzing an incoming packet for its destination address as soon as : the header arrived at the NIC, and so they have the chance to route it : before the entire packet went in. This is something you cannot : achieve with the traditional NIC architecture used in a Unix machine. : For an FDDI interface, this might get you 80 Mbps, as opposed to the : `lame' 45 Mbps of your Unix solution. (Or, translated to the standard : Ethernet, 800 kbps for a hardware router, as opposed to 400 kbps for a : Unix-based solution.) Are you referring to routing on a single ethernet segment? If so I agree, but think it's a silly point.... I have setup a PC with bsdi software and 2 ethernet cards specifically to test routing speed. With a small static routing table I got 850 KBS+ at something like 3% CPU utilization. What is likely to decrease from accepting a whole packet before analyzing it for forwarding information is not max thruput but latency. Yes, the packet will take an extra millisecond or two to be read in. If sub millisecond forwarding times are a requirement, hardware routers certainly have the advantage. But PC's can still route *well* above 400KB:) --- David