Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA
Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!ron
From: ron@brl-tgr.ARPA (Ron Natalie )
Newsgroups: net.lan
Subject: Re: (DoD) InterNet Header Checksum
Message-ID: <5363@brl-tgr.ARPA>
Date: Wed, 17-Oct-84 15:21:59 EDT
Article-I.D.: brl-tgr.5363
Posted: Wed Oct 17 15:21:59 1984
Date-Received: Thu, 18-Oct-84 19:12:41 EDT
References: <624@ttds.UUCP> <4985@brl-tgr.ARPA> <1723@sun.uucp> <> <222@celerity.UUCP>
Organization: Ballistic Research Lab
Lines: 13


> There are good reasons not to perform header checksums in TCP/IP other that not
> being clever enough to do one's complement arithmetic. If you are running your
> network strictly on Ether the time to calculate them is wasted because the
> Ether CRC does a much more rigorous job of error detection than does a one's
> complement checksum.

Well, we manage to get some checksum errors on the Ether even with it's
more rigorous checksum.  I suggest that you just put a reasonably efficient
(like I said, IP checksum is 24 instructions on a PDP-11) cksum in and forget
about it.

-Ron