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From: Mills@UDEL.EDU
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  ICMP in ISO
Message-ID: <8704162256.a010219@Huey.UDEL.EDU>
Date: Thu, 16-Apr-87 22:56:04 EST
Article-I.D.: Huey.8704162256.a010219
Posted: Thu Apr 16 22:56:04 1987
Date-Received: Sun, 19-Apr-87 10:21:58 EST
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We should not lose sight of the fact that echo mechanisms are embedded in
many protocols besides ICMP. Both TCP and UDP have echo ports, for
example. DECnet has an echo "mirror" mechanism as well. We might argue
about the detail protocol involved or whether it belongs as an intrinsic
feature of each protocol (as I believe) or belongs in a pervasive network
management, but I think we can all agree the mechanisms are necessary for
any real network. As one who often has had echo goo smeared up to my
clavicle, I can observe there have been numerous cases where something
was found to be working just fine at the IP level was broken at the
TCP/UDP level as diagnosed by the TCP/UDP echo mechansim. I submit
we shouldn't stop at ICMP and should strive for these mechanisms at each
and every level in the protocol stack.

DavU>