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From: "James_W._Morrison.ESAE"@Xerox.COM
Newsgroups: comp.dcom.sys.cisco
Subject: Re: strange behaviour involving repeaters
Message-ID: <23140@boulder.Colorado.EDU>
Date: 5 Jul 90 21:41:26 GMT
Sender: daemon@boulder.Colorado.EDU
Lines: 30


Greg;

Try changing the tranceivers on on either side of the repeater
one at a time.  Sometimes tranceivers will break packets when
heavily loaded with traffic (especially if they go flacky and
not totally break).  If the tranceivers don't fix the problem
then the repeater has to be breaking packets either because
it can't handle the traffic load or it's flacky.

If all else fails hook an o-scope up to the ethernet using
a "T" adapter in series with the terminated end and look for
broken packets (packets with an amplitude of more than -2 volts).
The broken packets may all be mangled or only a portion of the
packet near the end.  Disconnect the reapeater and see if the
broken packet condition still exists.  If so you have a machine
or tranceiver somewhere on that physical segment that's
flacky/broken.  Using the buddy system go and disconnect each
machine on taht segment one at a time until you find the
mangler.  Walla fix this guy and all will be well.

The reason this causes problems on both sides of the repeater
is that it looks like an open and repeaters only pass what they see
and don't try to "qualify" any packet, good or broken.

hope this helps,
Jim Morrison
Network Systems Analyst
Xerox Corp.
El Segundo, CA.