Re: [DNA] Issue 6: DNAHostLinkIDList

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

Since I didn't hear any other objections, I am going start closing the 
issues using the suggested changes, except for this issue on 
DNAHostLinkIDList.

My proposal for removing DNAHostLinkIDList is as follows:
We remove the concept of identifying a particular prefix as LinkID 
prefix and mandate the inclusion of the smallest prefix in all RA 
messages. On the host side, we only need to check if there is a prefix 
included in the RA that is in the DNAHostPrefixList. This will work if 
we make sure that when there is a change in the smallest prefix, the RA 
includes the previous smallest and the current smallest (similar to what 
is done when the LinkID changes now). So, the algorithm will be:

For non-landmark RA or a NO landmark response:
Router SHOULD try to send a completeRA.
If the completeRA is not possible due size restriction, the RA MUST 
include the smallest prefix.
If the smallest prefix was first seen within 1.5 hours ago, then the 
second smallest prefix MUST be included in the RA.
If the second smallest prefix was first seen within 1.5 hours ago, then 
the third smallest prefix MUST be included in the RA.
And so on... (I don't like that this is open ended, but thats how things 
are right now with including LinkIDs)

For unsolicited RA:
MAY be a completeRA.

If not a completeRA, same rules as above to include the smallest prefix(es).

What I am trying to do here should be obvious. The functionality is 
exactly the same as the LinkID component of the current draft, but there 
is no explicit marking as such and more importantly no explicit LinkID 
check at the host. The overlapping prefix check covers that for us, 
removes the need for a DNAHostLinkIDList, thus simplifying the operation 
significantly on the host side.

For future non-prefix linkIDs, they can be included in the LPO and they 
MUST be 128 bits long. Since LPO cannot be used to configure addresses 
this won't cause any trouble and cannot overlap with other prefixes 
since they are 128 bits.

I would like to know if people think this is workable - am I overlooking 
something?

- Sathya

JinHyeock Choi wrote:
>> I can't see how you can remove the DNAHostLinkIDList without removing
>> the concept of LinkID itself. As I mentioned in issue 2, we will mandate
>> the inclusion of the "smallest" prefix in the RA, particularly the
>> multicast RA, and achieve the advantage of LinkID, but remove the
>> complexity. I am not 100% sure about this either, but I can't think
>> anything wrong with doing this. Lets think it over.
>
> I am ok to remove DNAHostLinkIDList but am not sure about removing
> 'LinkID' itself. I agree that we would think this over further.
>
> Best Regards
>
> JinHyeock