[DNA] Possible way forward: combining Link ID and Landmark?

[Pekka Nikander <pekka.nikander@nomadiclab.com>]

[As I wrote earlier, I haven't been able to follow the ML discussion,  
and won't.  My sincere apologies.]

Based on what I heard during the WG meeting on Thursday and in some  
discussions afterwards, the following proposal occurred to me.  It  
may be completely off the mark.  If so, please ignore it.  I am  
offering this just in the case it might be useful and let the WG to  
move forward.

Would the following work?

   1. Define a new Link ID RA option, as in the Link ID draft.

   2. Define new Landmark RS and RA options, as in the landmark draft.

   3. Routers in a link are encouraged to create a Link ID and  
announce it, but not required.  [Details need to be filled in, e.g.,  
if all routers need to agree etc.]

   4a. A host that arrives on a link *with* a Link ID picks the Link  
ID as its landmark.

   4b. A host that arrives on a link *without* a Link ID picks one of  
the prefixes as a landmark, just as in the current landmark draft.

   5. When a host detects that it may have changed links, it looks  
for a landmark (as in the landmark draft) unless it gets a Link ID  
(as the landmark) very quickly (as in the case of FastRA-like  
optimisation).

Based on my very partial understanding, the above outline might  
work.  However, it may also be more expensive (in term of bytes or  
packets) than the current proposals.  On the other hand, it might  
also be more flexible or robust.

Maybe someone could do further thinking and analysis.

--Pekka