Hello,

<Pascal>  I'm sure you mean addresses that are formed using a link-layer
address, not just Link Local. More in section 5.7
 </Pascal>

Yes of course! I guess though what I really meant is that according to the
draft, save for the 6LR(s) address(es), a link-local address based on the
EUI-64 is the only address a 6LN could send to directly.

This is a limitation of the 6lowpan-nd draft, if I am reading this
correctly. I'm not trying to argue for or against such a limitation, just
everyone should be aware of it, and if this is not acceptable look for a
solution.

It would be good to have some confirmation from the authors to ensure I'm
not just being stupid, something we can never rule out ;-)

Regards,

  -Colin O'Flynn

-----Original Message-----
From: Pascal Thubert (pthubert) [mailto:[email protected]] 
Sent: March 8, 2011 2:03 PM
To: [email protected]; Stok, Peter van der
Cc: 6lowpan 6lowpan
Subject: RE: [6lowpan] nd-15 for isolated network

Hi:

<Colin>
The link-local address based on EUI-64 can always be mapped directly to
a L2 address. This is a special case, no other address can be mapped
that way according to the spec.
</Colin>

 
<Pascal>  I'm sure you mean addresses that are formed using a link-layer
address, not just Link Local. More in section 5.7
 </Pascal>


<Peter> In the applications I am involved, the bulk (say >90%) will be
messages > to one hop neighbors and possibly two-hop neighbors.
Actually, I expect that the quality of the link between source and
destination can be better than the link quality between source and 6LBR.
(people may argue that this is bad network engineering, but given costs
and knowledge today it looks a very probable situation) 
</Peter>


<Pascal>  What's more troubling for Peter's point about 1-hop neighbors
is in 6.1:
"
   A router MUST NOT set the 'L' (on-link) flag in the Prefix
   Information options, since that might trigger hosts to send multicast
   Neighbor Solicitations.
"
This text prevents a node from checking whether another node is visible
at L2. I think that this recent addition is a mistake. Though clearly
costly on a mesh under, this could be reasonable in some route over
cases, as long as the multicast is not forwarded. 

What this spec should mandate is whether and how to enforce the
registration for a given prefix as opposed to classical ND. The 'L' bit
does not say that. We need a new bit.
 </Pascal>

Cheers,

Pascal

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