Date: Wed, 25 Feb 1998 12:24:11 +1030 From: Greg Lehey <grog@lemis.com> To: Chris Dillon <cdillon@wolves.k12.mo.us>, Adam Turoff <AdamT@smginc.com> Cc: hackers <hackers@FreeBSD.ORG>, Robert Glover <rob@f-body.org> Subject: Re: Token Ring for FreeBSD yet? Message-ID: <19980225122411.62329@freebie.lemis.com> In-Reply-To: <Pine.BSF.3.96.980224192042.29916B-100000@duey.hs.wolves.k12.mo.us>; from Chris Dillon on Tue, Feb 24, 1998 at 07:26:57PM -0600 References: <34F37C2A@smginc.com> <Pine.BSF.3.96.980224192042.29916B-100000@duey.hs.wolves.k12.mo.us>
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On Tue, 24 February 1998 at 19:26:57 -0600, Chris Dillon wrote: > > > On Tue, 24 Feb 1998, Adam Turoff wrote: > >> But...but...but... >> >> Token Ring is the most expensive, slowest networking protocol on the >> planet(*). Why wouldn't a slick, fast OS like FreeBSD support it? >> >> Realistically speaking, aren't there bridges that can translate >> Token Ring to Ethernet? If you're installing FreeBSD, it's stupid >> not to use Ethernet. The h/w is cheap and the OS support is solid. >> >> The other 99% of the computers on your LAN are the anomaly, not >> the ethernetted FreeBSD box. >> >> (*) SneakerNet is slower, but costs less. :-) > > I wouldn't exactly call Token Ring slow just because it is only running at > 4 or 16Mbit. Correct. There are other reasons to call it slow. > The 16Mbit Token Ring network could run circles around any 10Mbit > Ethernet network. I disagree strongly with this statement. > On a heavily congested network, even a 4Mbit Token Ring network > could outrun a 10Mbit Ethernet network, simply because of the > token-passing scheme that Token Ring uses. On a normal network, a 10Mbit Ethernet network could outrun a 16Mbit Token Ring network, simply because of the token-passing scheme that Token Ring uses. > CSMA/CD just isn't very efficient on a heavily loaded network. The > CSMA/CD network (Ethernet) would spend more time dealing with > collisions than it would passing usable data. Correct. But token passing isn't very efficient under any kind of load. > FDDI and Arcnet have the same advantages. So why are they both so popular? > There was even an 80Mbit Arcnet proposal at one time, which would > have been much better than Ethernet. Frankly, I would consider > Ethernet just above SneakerNet in the protocol arena, not the other > way around. :-) I did some theoretical calculations a while back to show the amount of overhead in CSMA/CD and in token passing. I've forgotten the details, and I can't find the calculations, but the token-passing overhead was much larger than you'd expect. It's rather like the difference between catching a train and taking a car. Ignoring the speed difference between cars and trains, the big problems are: - Cars can become very slow in traffic jams. Trains are not usually susceptible to traffic jams. - You have to wait for trains. Greg To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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