Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!caip!brl-adm!brl-smoke!smoke!mike@BRL.ARPA
From: mike@BRL.ARPA (Mike Muuss)
Newsgroups: net.unix-wizards
Subject: Re:  Just how reliable is NFS?
Message-ID: <4241@brl-smoke.ARPA>
Date: Mon, 29-Sep-86 13:27:06 EDT
Article-I.D.: brl-smok.4241
Posted: Mon Sep 29 13:27:06 1986
Date-Received: Sat, 4-Oct-86 10:32:15 EDT
Sender: news@brl-smoke.ARPA
Lines: 15

You seem to miss the point that the UDP checksum is an End-to-end
protection measure, while the Ethernet CRC is a link-level
protection measure.  In a one-ethernet system, the UDP checksum only
protects you from bad interfaces or bad software.  (By the way,
interface boards DO fail in such a way as to send in garbaged packets...
sometime get me to tell you about the board that mangled 50% of the
packets it sent.  Nice thing was, neither TCP nor UDP were upset, because
they were protected by their checksums...)

In a complicated network, such as the real InterNet, which at last count
had 150 networks operating connected together by scores of gateways,
end-to-end protection measures are *vital*, because you have no way
to know (or control) what technology is used to convey your packet.
Your error rates will vary.
	-Mike Muuss