Path: utzoo!attcan!uunet!munnari!murtoa.cs.mu.oz.au!cs.mu.oz.au!kre
From: kre@cs.mu.oz.au (Robert Elz)
Newsgroups: comp.dcom.lans
Subject: Re: Token Ring (was: Re: Info on LANs)
Message-ID: <1145@murtoa.cs.mu.oz.au>
Date: 3 Jan 89 13:00:50 GMT
References: <12786@cup.portal.com> <920001@hposdl.HP.COM> <10777@s.ms.uky.edu> <13137@bellcore.bellcore.com>
Sender: news@cs.mu.oz.au
Lines: 23

In article <13137@bellcore.bellcore.com>, karn@ka9q.bellcore.com (Phil Karn) writes:
> (The only time Ethernet *does* silently drop packets is when
> the destination host is down or somebody pulls the plug on an intervening
> repeater ...)

This is not quite true, ethernets drop packets when the receiving
controller isn't fast enough to handle the incoming packet rate.

This, and the independant ability to determine if the addressed host
is up and running, are probably the only real uses of the frame status
byte.

> I suspect you are referring to Logical Link Control Type 2

No he's not, that does protocol level acks, and the received bit in the
transmitted packet doesn't help at all.

As you, and others, have pointed out, all real protocols do acks in
packets (and that includes all the ISO stuff) .. apart from anything
else these acks serve as flow control, which (at least at any level
beyond the controller), the frame copied bit doesn't.

kre