Thicknet (was Re: BBS's)

From: Eric J. Korpela <korpela_at_ellie.ssl.berkeley.edu>
Date: Mon Nov 20 19:51:02 2000

> For older (classic) computers, the bus bandwidth won't support 100Mbps
> ethernet, so you have to go with one of the 10Mbps standards (I'll ignore
> the original 3Mbps.. :-)).

I've only found one place where it's a problem so far, with an NE2000 card
in a slow XT compatible the data rate (even at 10 Mbps) was too high for it
it handle without dropping packets. I solved that by getting a 3COM card.
I suppose it's a problem on other machines without buffered receivers.
Then again the bulk of my really slow machines are serial line connected.

> 10BaseT seems to have advantages when :
> The computers are spread out all over the building (which doesn't apply
> to my setup, where most of the networkable machines are next to each other)

There are other advantages of 10BaseT over 10Base2.

You can use a switch so you aren't sharing your entire bandwidth
among every machine.

You can go full duplex and avoid collisions.

You can mix 10 and 100 Mbps devices without slowing down the fast devices.

You might not need to rewire for gigabit ethernet.

Your attachment to the rest of the world will probably be RJ45.

> Against that :
>
> 10BaseT needs a hub. This is one more thing to find space for, one more
> thing to have to power, and one more thing that you have to maintain.

Hubs and switches are getting cheap and small. An 8 port switch is about the
size of 8 ports. The only reason to get a big old hub is if you want
vintage ethernet hardware. Fortunately my collecting bug stops at the
network connection.

> Adding a machine to a 10BaseT network means running a cable back to the
> hub.

Or adding a hub near the machine. I like a switch on each floor and a hub in
each room.

> The BNC connector is a lot faster to wire than that darn RJ45,
> particularly when you have fiddle about with the wires to get them to the
> right contacts. And the solid, metal, BNC connector would seem to be more
> reliable than the RJ45 as well.

No arguments there.

Another general complaint is that 10BaseT to 10Base2 media converters are
too damn expensive. You can't swing a live cat without hitting a coax
AUI tranciever in a junk bin, but I've never seen 10BaseT-coax converter
that didn't cost $100+.

Eric
Received on Mon Nov 20 2000 - 19:51:02 GMT