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

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

Erik Nordmark wrote:
> 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?
> 
> 
> Indeed.
> 
> But I think that we shouldn't constrain our thinking about the latter to 
> the case when only one router can answer the question about the 
> landmark; one could have the routers share this so that any of them can 
> answer the question.
> 
I agree that the routers on a link should share information.  If they
do, then isn't this similar to the cost of negotiating an explicit link
identifier, but with the additional cost of maintaining the "landmark"
information for the link as prefixes come and go?

Brett.