Path: utzoo!attcan!uunet!yale!cmcl2!ccnysci!alexis
From: alexis@ccnysci.UUCP (Alexis Rosen)
Newsgroups: comp.protocols.appletalk
Subject: Re: Ethernet vs LocalTalk
Message-ID: <1941@ccnysci.UUCP>
Date: 9 May 89 09:01:31 GMT
References: <278@suna.CMI.COM> <29995@apple.Apple.COM>
Reply-To: alexis@ccnysci.UUCP (Alexis Rosen)
Organization: City College of New York
Lines: 30

In article <29995@apple.Apple.COM> desnoyer@Apple.COM (Peter Desnoyers) writes:
>I just did a benchmark with 2 MacIIs, one Ethernetted [etc.]
>
>    LocalTalk (through a bridge) - 138kbit/s
>    EtherTalk (same wire)	 - 418kbit/s
>
> [etc., EtherTalk isn't a trivial win...]

OK. I've posted, here and in other groups, about just how brain-dead the
MacUser article was. I don't think that needs much rehashing.

What I would like to know is why the hell we can't get better performance
with EtherTalk on Macs? This performance is about one twenty-fifth the
nominal speed of EtherNet. Not something to make the speed junky's pulse race.

The fact is that protocol overhead can't begin to account for this. Most of
it has got to be in the particular implementation- drivers, bus, ET controller
chip, card design, etc.

On all >68000 macs, the bus bandwidth can't be a problem. NuBus can handle
something like 10 MBytes/sec even if you don't do block transfers. Certainly
it won't ever top out from EtherNet load.

The other three factors seem to be entirely in the hands of the card designers.
So why can't I get cards that work at 2-4 mbits/second??

---
Alexis Rosen
alexis@ccnysci.{uucp,bitnet}
alexis@rascal.ics.utexas.edu  (last resort)