Hi Erik: If the compressor is a router forwarding a packet into the lowpan, then it can not so it will not compress the checksum. The only node that can compress the checksum is the transport endpoint that sources the compressed packet.
Today, 99.9 percent of the packets that transit in such networks are data measurements transmitted from a sensor node towards an application that resides on a gateway or on the backbone. So it's worth the effort. Also, there are tons of legacy field buses protocols in that space that we will be tunneling over UDP/6LoWPAN. In that case also, the checksum will be elided. Pascal >-----Original Message----- >From: Erik Nordmark [mailto:[EMAIL PROTECTED] >Sent: mercredi 19 novembre 2008 15:42 >To: Carsten Bormann >Cc: Pascal Thubert (pthubert); Shoichi Sakane; 6lowpan; Geoff Mulligan >Subject: Re: [6lowpan] UDP checksum elide > >Carsten Bormann wrote: > >> One the way from the correspondent node to the 6lowpan node, an app that >> implements the ULTP computes the MIC to allow the compressor at the >> 6lowpan boundary to check it and, if that *and* the UDP checksum were >> correct, to compress away the UDP checksum. > >What happens if I have an application on a correspondent node which >sends a regular UDP packet? (i.e., without the ULTP MIC) How can the >compressor tell the difference between such a UDP packet and a UDP >packet which includes the ULTP MIC? > > Erik _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
