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From: mishkin@apollo.UUCP
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Ethernet Suffering
Message-ID: <34cd523c.c366@apollo.uucp>
Date: Mon, 11-May-87 15:11:00 EDT
Article-I.D.: apollo.34cd523c.c366
Posted: Mon May 11 15:11:00 1987
Date-Received: Wed, 13-May-87 07:23:14 EDT
References: <8705070548.AA10268@ucbvax.Berkeley.EDU> <34bd5209.c366@apollo.uucp> <6603@mimsy.UUCP>
Reply-To: mishkin@apollo.UUCP (Nathaniel Mishkin)
Distribution: world
Organization: Apollo Computer, Chelmsford, MA
Lines: 45

[[This is a reposting of my response to Mark Weiser's article.  This
  one is slightly different from my earlier one.  If I spend any more time
  trying to figure out how to (successfully) cancel a previously posted
  article, I think I'll go insane.  Sorry for the noise.  --mishkin]]

In article <6603@mimsy.UUCP> mark@mimsy.UUCP (Mark Weiser) writes:
>I think this is a misinterpretation of the comments.  I have seen
>Apollo networks exhibiting extremely poor performance when too many
>diskless nodes were accessing a single server.

I think there's some confusion here.  *I* was talking about the number
of diskless workstations per ethernet, not per server.  I thought that's
what other people were talking about too.

Further, I want to make clarification:  When I referred to 8-15 as being
the maximum number of diskless workstations (per ethernet), I was *merely*
quoting the numbers that appeared in the articles to which I was following
up.  (I.e. I don't claim to be an expert on the performance characteristics
of other manufacturers' equipment.)  I'll let the real experts clear things
up.

>Another angle: there are lots of reasons why performance could be different
>between these two systems.  It is premature to point the finger at the
>0/1 networking levels without more information.

Climbing further out of the hole which I seem to have been digging myself
into:  I agree with you.  I was not trying to make a definitive comparison
between rings and ethers.  I was simply trying to add some more information
to the discussion.  A number of people here (at Apollo) have said to
me "Come on, this really can't be an ethernet saturation problem."  Others
have extolled ring networks in even other ways that I can barely
understand.

Finally, before I shrink away, I feel obliged to point out that lest
anyone get the wrong impression, Apollo believes that both ring and ether
networks are fine ideas.  These days, one can buy Apollo's DN3000s with
either or both of a ring or ethernet controller and all your Apollo
workstations can communicate (and share files) over complex
ring/ether/whatever internetwork topologies.

-- 
                    -- Nat Mishkin
                       Apollo Computer Inc.
                       Chelmsford, MA
                       {wanginst,yale,mit-eddie}!apollo!mishkin