Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!ncar!boulder!daemon
From: hedrick@cs.rutgers.edu
Newsgroups: comp.dcom.sys.cisco
Subject: Re: strange behaviour involving repeaters
Message-ID: <23177@boulder.Colorado.EDU>
Date: 6 Jul 90 19:25:00 GMT
Sender: daemon@boulder.Colorado.EDU
Lines: 17

I'm always suspicious of vendors that claim somebody is sending data
"too fast for an Ethernet".  You may recall that a number of people
claimed that Sun was violating Ethernet specs, when it turns out that
their interfaces and/or software were simply not capable of dealing
with high traffic levels.  We heard a claim recently from a vendor of
fiber Ethernet that MCI's ran "faster than 10Mbps".  When we finally
traced this down through their technical people, we believe the
problem is that they simply can't handle as high packet rates as the
MCI.  The 10Mbps speed is a fairly fundamental feature of Ethernet
which should be determined by the controller chip (through I guess it
probably depends upon something like a crystal to do timing, so we
have to assume the cisco designer was competent enough to use the
right frequency crystal).  Apparently the firmware does determine the
minimum interpacket spacing.  If you suspect you are dealing with a
device that can't take packets as fast as the MCI can generate them,
you can always use the "transmitter-delay" interface parameter to
insert additional delay.