Path: utzoo!utgpu!water!watmath!clyde!rutgers!rochester!cornell!uw-beaver!uw-june!uw-entropy!quick!srg
From: srg@quick.COM (Spencer Garrett)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Why IP & TCP Precedence Query
Message-ID: <175@quick.COM>
Date: 10 Jan 88 22:18:39 GMT
References: <12364755541.47.PADLIPSKY@A.ISI.EDU> <12364818810.20.STEVENS@A.ISI.EDU>
Organization: Quicksilver Engineering, Seattle
Lines: 10


I think one of the biggest warts in TCP/IP is the stupid checksum spec.
Including noncontiguous, and sometimes nonexistent, fields in the checksum
insures that they will be slow and awkward to compute.  If you're designing
a new protocol, PLEASE have the checksum include all of, and only, your
header and data.  If you feel you can't trust your IP level to check its
own header checksum, then please recompute the ip checksum yourself; don't
pluck bits of that header out and pretend they're your own.  If the IP
header got mangled, you shouldn't even see the packet.  If that's not
true, you need to fix your IP module.  Let's hear it for layering.