Path: utzoo!attcan!uunet!husc6!linus!mbunix!bwk
From: bwk@mitre-bedford.ARPA (Barry W. Kort)
Newsgroups: comp.protocols.appletalk
Subject: Re: How to monitor AppleTalk networks
Message-ID: <32990@linus.UUCP>
Date: 26 May 88 15:49:03 GMT
References: <3282@phri.UUCP>
Sender: news@linus.UUCP
Reply-To: bwk@mbunix (Kort)
Organization: The MITRE Corporation, Bedford, Mass.
Lines: 23

Roy Smith asks about "Netwatch" programs on Appletalk.  Kinetics
ships a couple of Network Utilities with their FastPath Gateway.
Echo lets you identify the Appletalk Nodes on your net and ping
them.  When the net is acting flaky, some nodes disappear from
view or don't answer all the pings.  Look draws a graph of network
activity versus time, and also prints out diagnostic and routing
table maintenance packets.  These utilities, together with
the Chooser window, help us diagnose Appletalk problems.

For a while we had a section of Farallon's PhoneNet tacked on to
the end of our Appletalk.  Although PhoneNet is supposed to work
over longer cable lengths than Appletalk cable, we experienced
more anomalies when PhoneNet sections were tacked on.  When we
disconnected the PhoneNet section, performance returned to normal.

We suspect echos and standing waves are the culprit, caused by
impedance mismatches, but we don't have hard evidence.  The
phenomenon would be similar to TV ghosts caused by poor antenna
cabling.  It would be nice to have a CRT display which would reveal
echoes and standing waves so that cabling irregularities could be
more easily diagnosed and corrected.  Right now it's a black art.

--Barry Kort