Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!telebit!brian
From: brian@telebit.com (Brian Lloyd)
Newsgroups: comp.dcom.lans
Subject: Re: Ethernet Collisions
Keywords: ethernet fanout SQE heartbeat collision
Message-ID: <1991Apr16.045846.29774@telebit.com>
Date: 16 Apr 91 04:58:46 GMT
References: <4150@gmuvax2.gmu.edu>
Sender: news@telebit.com
Organization: Telebit Corporation; Sunnyvale, CA, USA
Lines: 17
Nntp-Posting-Host: napa.telebit.com

SQE simply asserts the collision signal momentarily during the
interpacket gap.  This is to let the interface know that the
transceiver is still alive.  Normally the interface ignores SQE
because it sees it at a particular time immediately following the
transmission of a packet but when you plug the transceiver into a
fanout box, everyone sees the SQE/collision signal and interprets it
as a remote collision because they didn't just send a packet.

I personally find the behavior of SQE to be annoying for this and
other reasons.  Turn off SQE and your "remote collision" problems will
be greatly reduced.

-- 
Brian Lloyd, WB6RQN                              Telebit Corporation
Network Systems Architect                        1315 Chesapeake Terrace 
brian@napa.telebit.com                           Sunnyvale, CA 94089-1100
voice (408) 745-3103                             FAX (408) 734-3333