Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!apple!apple.com!desnoyer
From: desnoyer@apple.com (Peter Desnoyers)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Number of TCP retries
Message-ID: <4723@internal.Apple.COM>
Date: 13 Oct 89 16:34:28 GMT
References: <242@spectra.COM>
Sender: usenet@Apple.COM
Distribution: usa
Organization: Apple Computer, Inc.
Lines: 19

In article <242@spectra.COM> pace@spectra.COM (William B. Pace) writes:
> 4) When programming an Ethernet controller (e.g. Lance chip), how many
>    times should the controller retransmit the packet when it detects
>    collisions and other errors before giving up and reporting an error
>    to the driver?

I believe the retransmission you are talking about is part of the Ethernet 
spec. I seem to recall that it is something like 10 times with (random) 
binary exponential back-off, and another 6 at the maximum random back-off, 
and then report an error. 

Check the spec - this is essential to the correct operation of the 
Ethernet protocol. With linear backoff, the protocol is unstable and 
vulnerable to congestion collapse. With exponential backoff but off by 
some factor from the spec you could get squeezed out or hog the bus.

                                      Peter Desnoyers
                                      Apple ATG
                                      (408) 974-4469