[e2e] purpose of pseudo header in TCP checksum

[Joe Touch]

Michael Welzl wrote:
>>In IPv4, the IP header checksum does cover the SA/DA - it covers
>>everything in the IP header, including the hop count. In IPv6, there is
>>no header checksum, of course.
> 
> ...which was a bad decision IMO, because it breaks the
> "IP over everything" model and will now lead to problems
> with mechanisms such as UDP Lite, where link layers are
> now required check the headers (but ONLY the headers)
> of things above. Yuck.

IPv6 _requires_ UDP checksums. UDP Lite already addresses this, and when 
used ALWAYS INCLUDES the pseudoheader. See RFC 3828.

IP still works over everything; things that work over IP need to know 
something about it, as always.

Joe
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 254 bytes
Desc: OpenPGP digital signature
Url : http://www.postel.org/pipermail/end2end-interest/attachments/20050215/77118761/signature.bin