From: vds7789@aw2.fsl.ca.boeing.com (Vincent D. Skahan)
Subject: Re: Apollo networking alternatives
Organization: none
Date: Mon, 25 Jan 1993 15:44:06 GMT

brunkow@btree.uucp (Susan Brunkow) writes:
>In about 6 months, we'll be moving 50 Apollos into a new building.
>Currently, almost all of these machines are on Apollo Token Ring,
>except for two that are on ethernet. I'm getting a lot of
>"encouragement" to not use coax in the new building.
>The hardware is mostly DN4500's, DN2500's, DN3000's,
>and about 6 HP425t's. Our other networks (PC, Sun, and
>Macintosh) are all on ethernet, running mostly on twisted
>pair.

>1) Put everything on ethernet, using twisted pair cabling.
>This would let us use the same wiring that our Sun, Mac
>and PC networks are using. But I've heard that 
>Apollos are a pain on ethernet.

when you say 'put on ethernet', I'm assuming that you mean that
you want your token ring hunk'o'wire to be the regular ethernet.
You don't expect to just plug a 50-node apollo network into 
ethernet like a real unix node and have it magically work I hope.

Assuming you meant that you want to use ethernet as the wire,
many of the 'normal' apollo diagnostics don't work when you're
running the token ring over an ethernet wire (no matter what 
Apollo says).  That makes debugging a pain, but it does work ok.

Also, you want a segregated 'ethernet' for the token ring because
unless your router is programmed right, you might find that it's 
allowing other folks to see your token-ring packets.  Many people
set up their routers to pass everything by default.
(which is either a bug or a feature depending on your needs).

Moral of the story is that if you want to use ethernet for the
physical wire for the ring, make it a segregated ethernet if you can.

>2) Fibermux makes boxes which allow you to run ATR on
>twisted pair. This would be less expensive, since we wouldn't
>need to replace all of our network boards, and it should be
>faster, since it's still ATR. I've heard good reviews of these from
>a couple of people, and some negative comments from one
>person. We're leaning heavily towards this option right now.

I've run apollo-over-ethernet where the ethernet was twisted pair
and lattisnet hardware and it worked fine...I think there are distance
limitations that you need to be aware of, but I forget the numbers.

>If you have any experience with 50 or so Apollos on
>ethernet, or with the Fibermux setup, please
>e-mail me or call me. I'd really like to know what
>I'm gettin in to here. If there are some other, better
>options that I've missed, I'd like to hear about them.

we run Fibermux 'Lightwatch' stuff here for >200 apollos that are
wired over IBM-type-1 wire (gross).  The Fibermux hardware is supposed
to be smart enough to detect problems and automatically jump apollos
out of the ring automatically, but we've found that we can break it
very easily. 

	- don't have the trnasceiver switch that picks twisted pair 
		or 9-pin in the wrong setting or the ring hangs.

	- the usual apollo s/w problems (plugging a node with net-1
		into a ring with net-2 software network IDs) still
		breaks the ring.

	- I've heard of high breakage rates with the transceivers,
		but I haven't experienced them.

	- after a power failure, the software sometimes comes up
		with cards/ports that aren't enabled the same way
		as before (therefore the ring is broken or large
		numbers of nodes are missing from an lcnode).

These aren't bitches (yet) since we have Fibermux coming in this
week for a 2-day beating by all the APollo admins and networking
dudes :-)   

The Lightwatch software is pretty cool though, since when a break
occurs you can jump a port/card/chassis/closet/building out with 
one click of the mouse...

-- 
   ---------   Vince Skahan   ----- vds7789@aw101.iasl.ca.boeing.com ------- 
   I make it a point to always have something from each of the five basic 
   food groups....salt, sugar, fat, grease, and alcohol.