Subject: Re: [netlmm] question on the DHCP-PD

From: Julien Laganier <[email-masked]>
Date: Wed, 03 Dec 2008 10:38:29 +0100

Fan,

fan zhao wrote:
> On Wed, Nov 26, 2008 at 5:06 AM, Julien Laganier wrote:
>> On Wednesday 26 November 2008, fan zhao wrote:
>>> <[email-masked]> wrote:
>>>> On Friday 21 November 2008, fan zhao wrote:
>>>>> My question is when the MN connects to a source access network
>>>>> using PMIP (or other type of network
>>>>> based mobility protocol), it obtains a home network prefix. Then
>>>>> the MN handovers to a target access
>>>>> network (i.e. the foreign link for the MN) using the Mobile IPv6.
>>>>> The handover procedure is as follows.
>>>>>
>>>>> 1) The MN obtains a care-of address from the target access
>>>>> network. 2) The MN discovers the home agent if it does not know.
>>>>> 3) The MN sets up the IPsec SA with the HA if it does not have the
>>>>> SA with the HA before.
>>>>> 4) During the step 3), the MN requests the HNP allocated from the
>>>>> HA based on RFC 4877/5026.
>>>>> 5) The MN realizes it is on the foreign link, then it needs to
>>>>> send the BU to the HA.
>>>>> Since the Mobile IPv6 BU can only register the binding between the
>>>>> CoA and one single home address,
>>>>> in order to register the binding between the HNP and the CoA, the
>>>>> MN needs to use
>>>>> the NEMO extensions, for example, by setting up the 'R' bit and
>>>>> using the implicit mode.
>>>> There's no need to involve NEMO. You are confusing the notion of
>>>> Home Network Prefix with that of a NEMO Mobile Network Prefix: The
>>>> Home Network Prefix is a prefix advertized on the Home Link (by the
>>>> HA or a router in MIPv6 case, or a MAG in PMIPv6 case), while a
>>>> NEMO Mobile Network Prefix is a prefix delegated to a Mobile Router
>>>> and advertised in the Mobile Network. These are different cases.
>>> I completely agree with you on this. The home agent needs to know and
>>> set up the states for both the home network prefix and the mobile
>>> network prefix even though they may be the same.
>> The whole point is: The case where the Home Network Prefix and the
>> Mobile Network Prefix are the same doesn't make any sense in the
>> context of NEMO.
>>
>> The Home Network Prefix is advertized and used on the point-to-point
>> link between the MAG and the MN - or MR in the case we're discussing.
> That is correct in the PMIP domain. However, when the MN handovers to
> a foreign access network with the MIP used, the Home Network Prefix can
> be associated with the MN's logical/physical interface, right?

Why? The MN has Home Address(es) configured within the Home Network 
Prefix. If it goes away from home, it register said Home Address(es) 
with its Home Agent.

Without putting PMIPv6 in the picture, this is what happens with plain 
Mobile IPv6, i.e. the MN does not create a binding for the whole Home 
Network Prefix advertized on the Home Link, it simply creates binding 
for its Home Address(es).

Since the mechanism work just fine for a Mobile Node moving from a 
PMIPv6 Home Link to a foreign access network and thus needs to use 
MIPv6, there's no reason for "the Home Network Prefix [to] be associated 
with the MN's logical/physical interface", as you put it.

> Note that the case what I talked about is that a plain mobile IP terminal
> (not a MR) handovers between the PMIP and CMIP access network.

I understand that perfectly. I am saying that MIPv6 as-is handles both 
the case of a MN doing a handover from a MIPv6 home link to a foreign 
network, and that of a MN doing a handover from a PMIPv6 home link to a 
foreign network.

Thus there's no need to extend MIPv6, PMIPv6, or involve NEMO, and DHCP 
PD in the picture.

I am not going to reply to the rest of your note since I do not agree a 
protocol extension is required.

Regards,

--julien
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---

From: "fan zhao" <[email-masked]>
Date: Wed, 3 Dec 2008 11:21:01 -0800

Hi Julien,

Thanks for your reply.
The reason that I was proposing that the HNP option be included
in the MIP BU is to reduce overhead during binding registration when
the MN configures multiple IP addresses from the home network prefix.
If the WG believes this is not necessary, I am fine with it.

On the other hand, the DHCP PD is a separate issue. I will start
a separate thread and without ccing to NETLMM ML.

Sincerely,
fan

On Wed, Dec 3, 2008 at 1:38 AM, Julien Laganier
<[email-masked]> wrote:
> Why? The MN has Home Address(es) configured within the Home Network Prefix.
> If it goes away from home, it register said Home Address(es) with its Home
> Agent.
>
> Network Prefix advertized on the Home Link, it simply creates binding for
> its Home Address(es).
>
> Since the mechanism work just fine for a Mobile Node moving from a PMIPv6
> Home Link to a foreign access network and thus needs to use MIPv6, there's
> no reason for "the Home Network Prefix [to] be associated with the MN's
> logical/physical interface", as you put it.
>
> I understand that perfectly. I am saying that MIPv6 as-is handles both the
> case of a MN doing a handover from a MIPv6 home link to a foreign network,
> and that of a MN doing a handover from a PMIPv6 home link to a foreign
> network.
>
> Thus there's no need to extend MIPv6, PMIPv6, or involve NEMO, and DHCP PD
> in the picture.
>