Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!lll-crg!lll-lcc!pyramid!hplabs!amdcad!phil
From: phil@amdcad.UUCP (Phil Ngai)
Newsgroups: net.lan
Subject: Re: thin Ethernet advice wanted
Message-ID: <12831@amdcad.UUCP>
Date: Mon, 25-Aug-86 18:59:05 EDT
Article-I.D.: amdcad.12831
Posted: Mon Aug 25 18:59:05 1986
Date-Received: Tue, 26-Aug-86 00:39:58 EDT
References: <436@svax.cs.cornell.edu> <210@pwcs.UUCP> <3654@hplabsb.UUCP> <362@ssl-macc.co.uk>
Reply-To: phil@amdcad.UUCP (Phil Ngai)
Organization: AMD, Sunnyvale, California
Lines: 41

In article <362@ssl-macc.co.uk> ray@ssl-macc.co.uk (Ray Saxton) writes:
>
> We have a site with 16 suns and 2 vaxes, and have been running thinnet
>with 3Com boxes for about a year now with no major problems. Each office
>has several "barrel" connectors available for hooking in transceivers as
>required. Although 3 floors of the building were wired as a single 
>segment of some 200 mtrs, it has been found prudent to trim this as 
>transfers between the end nodes were not 100% reliable.

According to the DEC _Networks and Communications Buyer's Guide_, page
2.102, "ThinWire Ethernet is good for 185 meters and only 30 devices.
How many devices did you have?

>and more annoyingly was the reaction of both DEC and SUN "engineers"
>on seeing the thinnet. That won't work. Thats not 10mtrs ....on and on and on

What?

>This is blamed on the thinnet by both sets of Engineers, despite tests 
>that proved that cable length did not affect the ability of certain sites
>to communicate nor  the inability of the others to communicate.

I wouldn't consider this a definitive test. Some devices may have more
margin than others, that doesn't mean your cable plant isn't beyond
spec.  In particular I believe that 3Com boxes are designed with extra
margin and so their ability to work doesn't mean you can expect other
Ethernet compatible equipment to work.

> We have
>finally resolved the problem by hooking the VAxes via Delni and then hooking
>that into the despised thinnet via the good H4000. My only worry is
>what happens if that H4000 goes to meet its forefathers.

Sounds like you're living on borrowed time to me.

-- 
 Rain follows the plow.

 Phil Ngai +1 408 749 5720
 UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil
 ARPA: amdcad!phil@decwrl.dec.com