Re: [nemo] multiple CoAs registration

Hello Nicolas

thanks for comments.

> Hi Ryuji,
> 
> I read your draft on multiple CoAs registration and I also think that we 
> really need to define a solution to use MIPv6 with a multiple interfaces 
> MN.
> 
> Here are some comments on your draft:
> 
>    - Why do you introduce the interface identification (IFID) ? It could 
> be sufficient to only register a CoA with the associated priority. 
> Therefore, when the MN has to choose the destination address for a HoA, 
> it can take the most preferred CoA, which is bound to the most preferred 
> interface of the MN.

Priority can be changed by some reason during communication, but IFID
can not be changed until MN want to change it.

> Anyway you use a one-to-one mapping between a CoA and a IFID, therefore 
> you don't need both, or I missed a point ?
> 
> IMO, this is easier than all the mechanism to manage the IFID 
> (generation, maintenance...)

could be,  but I don't know why the maintenance and generation are so
difficult.

>    - If I well understand your draft, when the MN registers a CoA with a 
> CN, the MN has to first register the primary CoA. Then it can send a 
> Binding Update (after the RR procedure) to regsiter other CoA(s), with 
> the associated priority. However, you say that the lowest priority is 
> the preferred CoA/IF, and that the primary CoA has the priority 0. 
> Therefore, each CN will use the primary CoA with the MN. Then, you are 
> not able to perform load balancing, aren't you ?

Well, the draft does not mention about how to utilize multiple care-of
addresses. I don't think MIP is only way to manage policy sets to divide
flows to each CoAs. If you really want load-balancing, you need some
mechanism to maintain policy sets between MN and CNs.

Load-balancing, for example, can be supported by upper
layers.
The point is that CN must be able to accept packets sent from multiple
.CoAs of MN. 

>    - Last point: If you return home with your primary interface (you 
> connect to your home network with P-IF), do you have to de-register all 
> CoA (P-CoA and NP-CoA) with both your HA and CNs (see section 7.8) ?

You are right. I personally got the same comment. 
I just keep protocol simple. 
I will update the draft before the next meeting.

thanks again!

regards,
ryuji