Re: [MEXT] IETF-80 meeting minutes posted / clarifications on draft-liu-mext-distributed-mobile-ip

[<[e-mail]>]

Hi guys,

Julien, thanks for the minutes.

I didn't attend the meeting but I went through the recorded session and it seems there is couple of misunderstanding on item 5. Distributed Deployment of Mobile IPv6 (draft-liu-mext-distributed-mobile-ip-00). So, please let me, as co-author of this draft, try to clarify things:

This draft includes considerations on deployment of current mobile IP in distributed mobile architecture. This is a basic deployment where each access router supports the HA function. Maybe it's not optimal but it does not require modifications of MIP. The use-case is as follows:

Consider a MN attached to the access router AR1. If the MN initiates a flow (flow#1), flow#1 is routed in a standard way as long as the MN remain attached to AR1.

If the MN performs handover to a new access router, AR2: 
- flow#1 remains anchored to AR1, which now plays the role of HA. Data are tunnelled between AR1/HA1 and the MN.
- If the MN initiates a new flow (flow#2), flow#2 is routed in a standard way as long as the MN remain attached to AR2.

In other words, one flow is anchored (flow#1) and the other flow (flow#2) is not anchored.

If the MN performs handover to a new access router, AR3:
  - Flow#1 remains anchored to HA1/AR1. Data are still tunnelled between HA1/AR1 and the MN.
  - mobility support of AR2 comes into play and flow#2 is anchored to AR2/HA2. Data are tunnelled between AR2/HA2 and the MN.

In other words, both flows are anchored to two different HAs (flow#1 on AR1/HA1 and flow#2 AR2/HA2).

Here, there is no HA selection issue since, when the MN performs handover, the previous AR becomes the mobility anchor for IP flows initiated on it. 

IMHO, the "multiple home addresses" feature was misunderstood during the meeting. It is not require that a MN attached to a HA uses severals HoAs. Actually, the MN can use several home addresses only when attached to several HAs. Considering the use-case above, it means:
- Flow#1 served by HA1/AR1 and uses HoA1
- flow#2 served by HA2/AR2 and uses HoA2

Home address selection: there was a confusion with source address selection.  Some applications can survive to IP handover and, thus, do not need mobility support. We just say that these applications should use a local address (CoA) as source address instead of an anchored address (HoA). 


Hope that clarifies.

Regards,
Pierrick

> -----Message d'origine-----
> De : [e-mail] [mailto:[e-mail]] De la part de
> Julien Laganier
> Envoyé : mardi 19 avril 2011 17:15
> À : [e-mail]
> Objet : [MEXT] IETF-80 meeting minutes posted
> 
> http://www.ietf.org/proceedings/80/minutes/mext.txt
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