Ftp-WG: Why redundant checksum

The IP checksum is mandatory, and changes at each hop as fields such
as TTL are modified.  However, intermediate systems along the forwarding
path don't necessarily need to do a full IP header checksum recalculation.
See RFC 1624, "Computation of the Internet Checksum via Incremental Update".

			-David Borman


> Date: Wed, 12 Feb 2003 04:11:16 -0500
> From: "Mohammad Awad" <[email protected]>
> To: [email protected]
> Subject: Ftp-WG: Why redundant checksum
>
> Hi all
> Is the checksum into the IP header is nessesarily calculated or modules can 
> ommit it and save the overhead of recomputing it at meny nodes along the 
> route, especially when the IP is being serving a reliable transport protocol 
> such as TCP which contains a another checksum for important fields inside 
> the IP header itself?