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From: mcc@WLV.IMSD.CONTEL.COM (Merton Campbell Crockett)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: more on Fletcher
Message-ID: <8912070306.AA07369@WLV.IMSD.CONTEL.COM>
Date: 7 Dec 89 03:06:18 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 20

John:

Unless we're talking about a simple link level interface rather than an intel-
ligent communication processor, I still fail to understand how negotiating an
additional or alternative checksum is going to help.  You state:  "The TCP
checksum is an end-to-end checksum."  Unfortunately, "end" in this case would
refer to the intelligent communication processor NOT its host system.

Most of the intelligent processors that I've had the (mis)fortune to deal
with make the assumption that there will be no errors between the board and
the TCP, UDP, TELNET, and FTP peer processes in the host system.  This prob-
len is common to all intelligent processors regardless of protocol or suite
of protocols they are designed to support.

If you want to minimize the possibility of end-to-end data corruption, you
need to implement an end-to-end protocol that will physically execute in
the host processor--to a large degree replicating features in TCP/IP--or
use a simpler interface and performing the IP, TCP, etc. in the host.

Merton