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From: hedrick@topaz.rutgers.edu.UUCP
Newsgroups: comp.dcom.lans
Subject: Re: ethernet analyzer
Message-ID: <13975@topaz.rutgers.edu>
Date: Fri, 14-Aug-87 15:36:19 EDT
Article-I.D.: topaz.13975
Posted: Fri Aug 14 15:36:19 1987
Date-Received: Sat, 15-Aug-87 18:03:07 EDT
References: <310@intvax.UUCP>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 22

We use the HP Lanalyser.  With the newest software, it will do a good
job of summarizing what is going on at level 2 of your Ethernet.  I.e.
traffic patterns, bad packets, and even a 2-d matrix of who sends to
whom.  However it doesn't know about anything above level 2.  In most
cases where we have network problems they involve misbehaving TCP/IP
implementations, not hardware problems.  It turns out that a Sun
running etherfind or tcpdump is the most useful diagnostic tool that
we have.  An IBM PC with MIT's netwatch isn't bad, but the Sun
software gives you a lot more control over what you want to look at,
and doesn't drop packets as often under heavy load.  (However the Sun
still can't keep up with an Ethernet that is fully used.  In a
broadcast storm, you'll generally see enough packets to be able to
figure out what is going on, but if 100 hosts send broadcasts at the
same instant, you won't see them all.)  I have heard rumors of some
competitor to the HP that has similar capabilities.  The other
advantage of the Sun is that you can direct output to a file and then
analyse it easily.  HP lets you upload statistics, but their serial
port runs DDCMP, and they don't supply any software for the host.  So
we haven't found any way to actually use the upload capability.
However the HP is a really solid piece of work, and anyone who is
doing serious work with Ethernet will probably want it or something
equivalent.