All good, Guangpeng. I missed (or more probably forgot over time) the 0/1 technique. So adding new nodes would not cause renumbering whereas rewiring will. That was good clarification. For hardwired networks (my sensor Xmas tree) the mechanism appears well-suited. A tree becomes as easy to use as a hub and spoke.
All the best, Pascal > -----Original Message----- > From: 6lo <6lo-boun...@ietf.org> On Behalf Of Liguangpeng (Roc, Network > Technology Laboratory) > Sent: mardi 23 août 2022 10:14 > To: Pascal Thubert (pthubert) <pthubert=40cisco....@dmarc.ietf.org>; > Pascal Thubert (pthubert) <pthub...@cisco.com> > Cc: Michael Richardson <mcr+i...@sandelman.ca>; 6lo <6lo@ietf.org> > Subject: Re: [6lo] Call for WG adoption of draft-li-6lo-native-short- > address-03 > > Hi Pascal, > > There is really misunderstanding here. I'll add explanation inline. > > Best Regards, > Guangpeng > > > -----Original Message----- > > From: Pascal Thubert (pthubert) <pthubert=40cisco....@dmarc.ietf.org> > > Sent: Tuesday, August 23, 2022 3:15 PM > > To: Liguangpeng (Roc, Network Technology Laboratory) > > <liguangp...@huawei.com>; Pascal Thubert (pthubert) > > <pthub...@cisco.com> > > Cc: Michael Richardson <mcr+i...@sandelman.ca>; 6lo <6lo@ietf.org> > > Subject: RE: [6lo] Call for WG adoption of > > draft-li-6lo-native-short-address-03 > > > > Hello again Guangpeng > > > > Seems that Michael and myself miss something in the address assignment > then. > > Maybe some text will help the next readers avoid that misunderstanding. > > > > Say you have this(fig 3 + some nodes) > > > > > > root +--------------------------+ > > 1 | append more bits to form > > | > > O ----+ | brother's address > > | > > / | \ \ +--------------------------+ > > / | \ \ > > / | \ \ \ > > +---------+ / | \ \ \ > > |forwarder| 10 / 11 110\ \ 111 \ XXX > > |node | O - O O O O > > +---------+/ |\ \ | \ | \ > > / | \ \ | \ | \ > > / | \ \ O O O O > > / | \ \ > > 100/ 1010| 101 1011 +--------------+ > > O O O O |Prefix is '10'| > > /| /| +--------------+ > > / | / | > > O O O O > > 1001 10011 10101 101011 > > > > > > And you add a core switch attached to root (XXX in the picture). How > > would you name it? I guessed 1110 because that's what would happen if > > XXX was present at the very initial time. > Yes, correct. As per Figure 4 in the draft. > > > But when XXX is finally installed, 111 must already have a child, > > otherwise why should it be there? That child is already 1110, and then > there's 1111 etc... > 111 is a leaf address, which mean there cannot be child address at any > time. In other words, nodes (except root) with address ending with '1' > must have no subtree. So 1110 is must not child of 111, it only can be > child of '1'(the root). We gave concrete example in the draft to explain > how figure 4's algorithm works. See Page 8-9. > > > > > So we have a collision for 1110. I (and I suspect Michael too) > > expected renumbering so you get the same addresses whether XXX is > > plugged at T=0 or later in the life of the network. > > If you have a different plan please document it. > > As clarified as above, there wouldn't be collision any more. > > > > Now, say that for operational issues you need to unplug 1011 from 10 > > and plug it to 11. Again, from my reading that's renumbering. What's > > the plan to avoid it? > > > This is a reasonable case, but the target new parent is surely not 11. But > it may be 110. We have moved solution of this case to another draft, see > section 3.2 in https://datatracker.ietf.org/doc/draft-li-nsa-reliability/ > . We expect people to input concrete requirements that cause topology > change and make the solution work for that. > > > All the best, > > > > Pascal > > > > > > > > > -----Original Message----- > > > From: 6lo <6lo-boun...@ietf.org> On Behalf Of Liguangpeng (Roc, > > > Network Technology Laboratory) > > > Sent: lundi 22 août 2022 11:04 > > > To: Pascal Thubert (pthubert) <pthubert=40cisco....@dmarc.ietf.org> > > > Cc: Michael Richardson <mcr+i...@sandelman.ca>; 6lo <6lo@ietf.org> > > > Subject: Re: [6lo] Call for WG adoption of > > > draft-li-6lo-native-short- > > > address-03 > > > > > > Hello Pascal, > > > > > > Please see inline. > > > > > > Best Regards, > > > Guangpeng > > > > > > > -----Original Message----- > > > > From: Pascal Thubert (pthubert) > > > > <pthubert=40cisco....@dmarc.ietf.org> > > > > Sent: Monday, August 22, 2022 2:18 PM > > > > To: Liguangpeng (Roc, Network Technology Laboratory) > > > > <liguangp...@huawei.com> > > > > Cc: Michael Richardson <mcr+i...@sandelman.ca>; 6lo <6lo@ietf.org> > > > > Subject: Re: [6lo] Call for WG adoption of > > > > draft-li-6lo-native-short-address-03 > > > > > > > > Hello Guangpeng > > > > > > > > If we take the DC sensors as use case and racks are organized in > > > > trees, and you add a new rack then there will be renumbering. > > > > > > No, it doesn't. Just attach this new rack to existing racks and > > > don't move existing racks to this new rack meanwhile. The latter > > > action is weird and superfluous. > > > > > > > > > > > This is why it’s safer to use this tech at L2. For the better and > > > > the worse IoT standards happen to use the IP address as a node ID. > > > > I was there when ISA 100 made that decision and I understand why. > > > > I see the same arguments applying in list constrained environments. > > > > > > > > Now say that NSA is an L2 address or an L2.5 address. You get > > > > redundancy by allowing a node to have more than one L2 address. > > > > Renumbering is OK by reassigning Mac/IP matches - though it has to > > > > be done carefully/transactional my as MACs are reassigned. > > > > > > > This is why the NSA mechanism try hard to avoid renumbering even > > > sacrifice the applicability of basic mechanism in wireless network. > > > Here, NSA is part of IPv6, hence it indeed a L3 address. So, I can > > > not understand why NSA would map to multiple L2 addresses. > > > > > > > Do it at L3 and you’re screwed. > > > > > > > BTW, I think derive IPv6 from L2 is not a reliable assumption > > > considering privacy issues and fake MAC problems. This is why we > > > need develop a short > > > L3 address in 6lo. > > > > > > > > Regards, > > > > > > > > Pascal > > > > > > > > > Le 22 août 2022 à 04:37, Liguangpeng (Roc, Network Technology > > > > Laboratory) <liguangpeng=40huawei....@dmarc.ietf.org> a écrit : > > > > > > > > > > Hi Michael, > > > > > > > > > > Thanks for the clarification. Please see below: > > > > >> If I insert a new device in the tree, then all of the tree > > > > >> below that device has to renumber. > > > > > Technically saying, it may exist but it seems weird to insert a > > > > > new device in > > > > the middle of the tree. When a user wants a new device, a normal > > > > way is append them to the network at the end of an existing rank. > > > > Totally, you mentioned a topology change manually, for which we > > > > put a sentence in Section 9 of the draft to hightlight this > consideration. > > > > > > > > > >> I also think that it can happen if I add a new device to an > > > > >> existing > > > rank. > > > > > No, as long as there is enough address for this new device. > > > > > > > > > > Cheers, > > > > > Guangpeng > > > > > > > > > >> -----Original Message----- > > > > >> From: Michael Richardson <mcr+i...@sandelman.ca> > > > > >> Sent: Monday, August 22, 2022 12:07 AM > > > > >> To: Liguangpeng (Roc, Network Technology Laboratory) > > > > >> <liguangp...@huawei.com> > > > > >> Cc: Alexander Pelov <a...@ackl.io>; 6lo <6lo@ietf.org> > > > > >> Subject: Re: [6lo] Call for WG adoption of > > > > >> draft-li-6lo-native-short-address-03 > > > > >> > > > > >> > > > > >> "Liguangpeng (Roc, Network Technology Laboratory)" wrote: > > > > >>> Thanks for share of Carpenter's draft. I fully agree with the > > > > >>> content of it after a quick read. I think it's for all > > > > >>> adoption process, not only for this adoption call. I believe 6lo > Chairs' > > > > >>> professional actions. > > > > >> > > > > >>> About the technical related concern: > > > > >>>> One concern that I have with NSA is that I think the network > > > > >>>> can get renumbered whenever there are new devices. > > > > >> > > > > >>> Can you explain a little more on how this problem happens? > > > > >> > > > > >> If I insert a new device in the tree, then all of the tree > > > > >> below that device has to renumber. > > > > >> I also think that it can happen if I add a new device to an > > > > >> existing > > > rank. > > > > >> > > > > >> > > > > >> -- > > > > >> Michael Richardson <mcr+i...@sandelman.ca> . o O ( IPv6 IøT > > > > consulting ) > > > > >> Sandelman Software Works Inc, Ottawa and Worldwide > > > > >> > > > > >> > > > > >> > > > > > > > > > > _______________________________________________ > > > > > 6lo mailing list > > > > > 6lo@ietf.org > > > > > https://www.ietf.org/mailman/listinfo/6lo > > > _______________________________________________ > > > 6lo mailing list > > > 6lo@ietf.org > > > https://www.ietf.org/mailman/listinfo/6lo > _______________________________________________ > 6lo mailing list > 6lo@ietf.org > https://www.ietf.org/mailman/listinfo/6lo _______________________________________________ 6lo mailing list 6lo@ietf.org https://www.ietf.org/mailman/listinfo/6lo
