Re: [DNA] Confirming today's face-to-face meeting decisions

[Brett Pentland <brett.pentland@eng.monash.edu.au>]

Sathya Narayanan wrote:
> Yes. The advantage in using a 'Link Identifier' with a scope
> applicable to all the nodes in the network is that the host will be
> able to determine whether it is on the same link or not from
> receiving a single (RA) message. On the other hand, when such
> identifier is not available, the host can ask the question 'does this
> landmark still exist' everytime it has (good) reason to believe it
> may have changed link.
> 
> Can we refer to the first scheme as 'link scoped identifier' and
> second as 'host scoped identifier' scheme? ;-)
> 
> The question to ask is, whether the cost of establishing the unique
> link identifier among all the nodes (routers) in the link is worth to
> avoid an extra 'does this landmark still exists' question and answer?

There may be extra cost in making all the routers on a link agree on
a "link scoped identifier", but that is an out of band management cost.
Using "does this landmark still exist" has a cost during movement in
that there is no negative acknowledgement and we have to wait for a
timer to expire if the link is new and the landmark does not still
exist.

Brett.