Path: utzoo!attcan!uunet!mailrus!cs.utexas.edu!sdd.hp.com!elroy.jpl.nasa.gov!ames!oliveb!felix!darnold
From: darnold@felix.UUCP (Dave Arnold)
Newsgroups: comp.dcom.lans
Subject: Do DELNI's cause collisions?
Message-ID: <145340@felix.UUCP>
Date: 24 May 90 18:29:20 GMT
Sender: daemon@felix.UUCP
Reply-To: darnold@felix.UUCP (Dave Arnold)
Organization: FileNet Corp., Costa Mesa, CA
Lines: 30


Rumor has it that DELNI's assert collisions, and may impact network
performance.  In other words, if the DELNI were attached to a coaxial
cable segment, and a LAN analyzer was monitoring collisions, and 9 stations
were transmitting (8 on the DELNI, 1 on the cable),
much more collisions would be seen with the DELNI
than if the 9 stations were just attached to the coaxial cable segment alone.

I have heard of this before and all the reports I have
heard have just been hearsay.

I asked our local DEC tech. rep. about this, and he initially never heard of
this problem.  But said he would look into it.

After doing some research, he called me back and said he didn't know
about the collisions, but did say that each port on the DELNI
are internally distanced so that the propogation delay parameters
are met. (??) And he said problems could result if you cascaded the DELNI's.

I still have no hard information regarding this.  I do know that
the tolerances for Ethernet are narrow.

Does anybody have any facts?


--------
Dave Arnold - FileNet Corporation
3565 Harbor Boulevard, Costa Mesa, Ca.  92626
PSTN: (714) 966-3906  FAX: (714) 966-3440  Telex: 383902
UUCP: hplabs!felix!darnold