Pascal - this is a clear and coherent description of why UDP checksum should be elided in some circumstances. Much better than my efforts earlier, and I think that you've addressed most of the concerns that were raised then. I think it's a great idea.
ksjp Pascal Thubert (pthubert) wrote: > Hi: > > Per RFC 4944: > "The UDP header's checksum field is not compressed and is therefore > carried in full." > > The UDP checksum is not the only way to protect the IP pseudo header, > the UDP header and the payload. > ISA 100.11a is defining a transport-level security that does all this > and more, since it has a larger signature and provides mutual > authentication at the same time. > > Also, the ISA100.11a transport-level security is usually > hardware-assisted, so it requires little power or CPU time on the field > device, whereas UDP checksum will be a costly CPU operation. > > So ISA100.11a is an example where the UDP checksum could and actually > should be compressed over the LoWPAN, leaving it up to be reconstructed > by a backbone router should the packet go any further than the LOWPAN > itself. > > Since bit 3 in the HC-UDP header is reserved anyway, it makes sense to > standardize it to mean that the UDP checksum is compressed, provided > that the headers and payload are equally or better protected than if the > checksum was used. > > Note: that would be bit 7 in my HC3 proposal. As a result, the complete > HC3 proposal could save us up to 4 additional bytes over RFC 4944 for a > UDP packet. > > What do you think? > > Pascal > _______________________________________________ > 6lowpan mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6lowpan > _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
