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
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