The question is, can data be corrupted without detection or correction, over 
TCP/IP? It seems like the checksumming used by TCP/IP is considered weak by 
modern standards. So there is the possibility of undetected and uncorrected 
corruption, but I don't know how probable it is.

I'm also confused by RFC 793's reference to "header and text" below. I can't 
tell what the word "text" is referring to. It seems like the checksum may only 
be checking TCP header info and not the data portion of the packet. Or does 
"text" in fact refer to the data portion of the packet?



http://tools.ietf.org/html/rfc793

    As long as the TCPs continue to function properly and the internet
    system does not become completely partitioned, no transmission
    errors will affect the correct delivery of data.  TCP recovers from
    internet communication system errors.


  Checksum:  16 bits

    The checksum field is the 16 bit one's complement of the one's
    complement sum of all 16 bit words in the header and text.  If a
    segment contains an odd number of header and text octets to be
    checksummed, the last octet is padded on the right with zeros to
    form a 16 bit word for checksum purposes.  The pad is not
    transmitted as part of the segment.  While computing the checksum,
    the checksum field itself is replaced with zeros.




Chris Murphy

_______________________________________________
MacOSX-admin mailing list
[email protected]
http://www.omnigroup.com/mailman/listinfo/macosx-admin

Reply via email to