Re: [DNA-BOF] Draft BoF agenda.

[JinHyeock Choi <athene@sait.samsung.co.kr>]

Dear Erik

Thanks for your elaboration. 

> I think the key question is what prefixes are assigned to the link
> and in this case both A and B apply. The same would be the case of
> both routers advertised both A and B, or if there was a single router
> advertising A and B.
> 
> I think the confusion is caused by the attempt to overload on-link prefixes
> to mean something different than intended. THeir meaning is: you can and
> should perform address resolution for an address that falls in the on-link
> prefix and send packets addressed to other routers to one of the default
> routers.

Thanks for your clarification. But kindly allow me one more question. 

Can we use on-link prefixes to check the validity of CoA? After a MN 
moves to a new link, if the current CoA falls in the on-link prefix, can we 
assume that CoA is still valid in a new link? 

I think so. But it seems to me that your definition of on-link prefix is a little 
weak for that. 

> RFC 2461 allows links that have no on-link prefixes i.e. where all packets
> would be sent to a default router (with the ability to redirect to on-link
> destinations).

If a MN moves into the link with no on-link prefix, how can it check the validity 
of the current CoA?  
 
> Thus as RFC 2461 is designed it is problematic to overload the on-link
> prefixes as some form of "link identifier".
> 
> I see two choices on how to proceed:
>  - revisit RFC 2461 and make all routers on the link advertise the same set
>    of on-link prefixes and require that at least one on-link prefix
>    be advertised on every link.

Interesting suggestion. I also thought about how a RA can act as 'link identifier' 
so that a MN can detect movement with the receipt of just one such RA. 

IMO, if a RA contains 1) all the on-link prefixes and 2) the indication that 
it contains all the on-link prefixes, it can act as 'link identifier'. 

Without such indication, I am worried that it may take too much bandwidth 
to make all routers on the link advertise the same set of on-link prefixes all 
the time. 

>  - introduce an explicit "link identifier" option in Neighbor Advertisements.
> 
>   Erik

Best regards

JinHyeock