Hi Carsten, > -----Original Message----- > From: Carsten Bormann [mailto:[email protected]] > Sent: vendredi 16 octobre 2009 12:39 > To: Julien Abeille (jabeille) > Cc: Zach Shelby; 6lowpan > Subject: Re: [6lowpan] Fundamental assumptions of > 6lowpan-nd-06: which procedures from which RFCs assume link > transitivity > > Great question. > Thank you > I would like to extend it to "which procedures from which > IPv6 RFCs assume link transitivity and/or > high-delivery-probability subnet-wide multicast", I would prefer asking questions individually before merging. Regarding the second question, we still have two disalignments: - "subnet wide" (this is a tough one as we have not discussed addressing yet) vs "one hop radio wide" . E.g. in route over for link local address resolution of 2+ hop neighors make no sense to me. Same with off link prefixes (which we are talking about I think) - some of us advocate that duty cycling techniques ensure high delivery probability one hop away: see Jonathan ("The whole discussion around sleepy nodes is problematic for me as well. The link is either up or down, not sort-of kind-of"), Adam's emails. Kris, can you give your TSCH view? > as these > are the assumptions violated by a LoWPAN (in most > configurations, excepting two-node and full-multicast mesh-under). > > Just one example for the former: RFC 4861 redirect assumes > that a router can tell a host that it can reach another host > via the same link. Not true in LoWPANs. > > The obvious RFC 4861 example for the problems caused by the > latter, i.e. (deliberate) lack of high-delivery-probability > subnet-wide multicast, is DAD. But there may be a lot of > other protocols hit by this. Is this a problem? > It would be if these protocols were likely to show up in > LoWPANs. One important assumption behind 6LoWPAN is that it > is not so likely that LoWPANs will be freely substituted for > Ethernet (in the sense that > 802.11 was essentially employed as an Ersatz Ethernet). Example: > People are not going to open their laptops and see, oh there > is a LoWPAN, and start using that for their normal Internet > access activities such as E-Mail and Web access (although > these two actually would pretty much work). > Agreed (just considering non transitivity), DAD and redirect fail.
> 6LoWPAN started out by saying "let's build an IPv6 link out > of 802.15.4", with the assumption it would then be like any > other IPv6 link. It took a couple of years to readjust that > assumption. People newly coming in from high-power IPv6 may > now also need some time to readjust theirs. > > Gruesse, Carsten > > _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
