[comp.protocols.tcp-ip] IP PDU header cksum algorithm question

husain@stsusa.com (12/19/89)

	Does anyone have the C source code (or algorithm in ENGLISH!)
	for calculating the checksum for the IP PDU header??

	The ISO 8473 annex gives a really wierd description of the 
	cksum algorithm using MODULO 255 arithmetic. HELP! What is 
	that ?????

	Thanks in advance

	kbh
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craig@NNSC.NSF.NET (Craig Partridge) (12/20/89)

Your note is a bit confusing because it talks about IP and then ISO 8473
and the checksums are different but, in either case, you want to read
a recent issue of Computer Communication Review.

For ISO checksums, see K. Sklower's article in the October 1989 issue.

For IP checksums, see R. Braden et. al. in the April 1989 issue.

Craig