*> From owner-ietf-outbound(_at_)ietf(_dot_)org Tue Aug 28 01:24:10 2001
*> Date: Tue, 28 Aug 2001 09:05:03 +0100 (BST)
*> From: =?iso-8859-1?q?jacob=20mathews?=
<jac_mat_ietf(_at_)yahoo(_dot_)co(_dot_)in>
*> Subject: TCP/IP check sum
*> To: ietf(_at_)ietf(_dot_)org,
UNEXPECTED_DATA_AFTER_ADDRESS(_at_)(_dot_)SYNTAX-ERROR
*> MIME-Version: 1.0
*> Content-Transfer-Encoding: 8bit
*> Content-Transfer-Encoding: 8bit
*> X-Loop: ietf(_at_)ietf(_dot_)org
*> Content-Transfer-Encoding: 8bit
*>
*> Hi,
*> On a etherent frame CRC is used for error detection.
*> For TCP/IP frames frame check is done by using 16bit
*> 1's complemet addtion.
*> Why is TCP/IP frame check required when the same is
*> verified by the ethernet MAC?
*> What is then the motivation of providing TCP/IP
*> checksum overload by some products?
*>
*> Waiting for responses.
*> thanking you,
*> jacob
Please see, e.g., the explanation in Section 11.3 of "TCP/IP
Illustrated, Vol. 1" by the late W. Richard Stevens (Addison-Wesley
1994). And may we suggest that you read the whole book?
Bob Braden
*>
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