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

[Sathya Narayanan <sathya@research.panasonic.com>]

JinHyeock -

<snip>
> Landmark approach don't have to be host scoped. Many hosts can share the same landmark.
It is the minimum requirement - similarly the same linkID can conceivably be used in more than one link (as long as they are further apart), I don't remember global uniqueness of LinkID being agreed upon. But, the linkID MUST ATLEAST BE the same within the link in one case (link scoped) and its enough if the host picks its own in the other (host scoped).

> 
> > 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?
> >
> > Link scoped identifier scheme requires completely securing the 
> link so that nobody can spoof a RA message or confuse the link 
> identifier, while we (I am not sure about this) may not need 
> complete security as long as a secure association between the host 
> and the current AR is good in the host scoped identifier approach.
> 
> Even with host scoped (?) approach, if there is only the secure
> association between a host and the current AR, the host can't securely
> detect that a link change has happened. The host can't receive a 
> secure 
> message confirming a link change when it actually happens.

In the host scoped approach, link change is inferred when the current landmark is not confirmed by the network (timeout) - I know, packet loss will have the same effect as link change and this becomes a additional cost for host scoped approach.

My only request is that we do a cost comparison (atleast a preliminary one) before deciding to go with either approach.

with regards,
Sathya