On Tue, 24 February 1998 at 19:26:57 -0600, Chris Dillon wrote:
> On Tue, 24 Feb 1998, Adam Turoff wrote:
>> 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
> 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.
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