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