I took the liberty to include the above layers in the minuted text indicating that it was my interpretation of Michael's words. Point is we are rarely using L3 security but rather transport.
Regards, Pascal Le 27 avr. 2016 ? 07:34, Thomas Watteyne <[email protected]<mailto:[email protected]>> a ?crit : Michael, I hadn't fully understood your comment on Friday. I do now, thanks. Thomas On Fri, Apr 22, 2016 at 7:06 PM, Prof. Diego Dujovne <[email protected]<mailto:[email protected]>> wrote: Michael, Thank you! Diego 2016-04-22 14:02 GMT-03:00 Michael Richardson <[email protected]<mailto:[email protected]>>: Pascal Thubert (pthubert) <[email protected]<mailto:[email protected]>> wrote: > * Michael: Layer3 (meaning and above NOTNT) Only one per > packet. Payload is > already 1000 bytes layer 2 on every packet. not reduce layer 2 security, > repeat it on every fragment. Cannot eliminate in that layer. To clarify. If one has a 1000 byte CoAP packet, split up into 8 layer-2 fragments, the layer-3 security will be applied once. So the overhead of the layer-3 security may be much lower *on average* than the layer-2 security. The layer-2 security will get repeated on each of the 8 layer-2 fragments. It would be wonderful if that layer-3 security could be used to eliminate the overhead of the layer-2 security, but that would open up our LLNs to being used to carry bogus traffic. (The OSCOAP layer-3 security can not be checked on a hop-by-hop basis without sharing the session key everywhere) Obviously, if one has an 80-byte CoAP packet, this calculation is not the same. -- Michael Richardson <[email protected]<mailto:mcr%[email protected]>>, Sandelman Software Works -= IPv6 IoT consulting =- _______________________________________________ 6tisch mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/6tisch -- DIEGO DUJOVNE Acad?mico Escuela de Ingenier?a en Inform?tica y Telecomunicaciones Facultad de Ingenier?a UDP www.ingenieria.udp.cl<http://www.ingenieria.udp.cl> (56 2) 676 8125 _______________________________________________ 6tisch mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/6tisch -- _______________________________________ Thomas Watteyne, PhD Research Scientist & Innovator, Inria Sr Networking Design Eng, Linear Tech Founder & co-lead, UC Berkeley OpenWSN Co-chair, IETF 6TiSCH www.thomaswatteyne.com<http://www.thomaswatteyne.com> _______________________________________ _______________________________________________ 6tisch mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/6tisch
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