Re: [Sipping] Request for Open discussion about SIP mobility

[Haruki Izumikawa <[e-mail]>]

Dear Paul,

Thank you for your comment. I cleary understand the process of this topic.

Regards,

Haruki


Paul Kyzivat wrote:
> 
> 
> Haruki Izumikawa wrote:
>> Dear Stefano,
>>
>> Thank you for your interest. I have reviewed your updated I-Ds. As you 
>> pointed, I also think that we share common requirements and scenarios.
>>
>> I understand the addition of a new SIP header could not be a major 
>> concern. In fact, I have proposed a new SIP header for bicasting 
>> before. But, I'm afraid that the addition of a new SIP header falls 
>> into terms of reference of SIP WG, not SIPPING WG. How do you feel 
>> about it?
> 
> That is true. But the work could and should start in SIPPING. If it 
> eventually is decided that a new header is needed then that work would 
> be shifted to the SIP WG with blessings from SIPPING. Since there is a 
> huge overlap in participation that should not cause any difficulty.
> 
>     Thanks,
>     Paul
> 
>> Best wishes,
>>
>> Haruki
>>
>>
>> Stefano Salsano wrote:
>>> Dear Haruki,
>>>
>>> thank you for restarting discussion on SIP mobility. I agree with the
>>> importance to discuss this topic in this WG.
>>>
>>> I'd like to bring again to the attention of the WG two related internet
>>> drafts that we submitted some time ago and that we've now updated
>>>
>>> [1] Requirements for vertical handover of multimedia sessions using 
>>> SIP http://tools.ietf.org/html/draft-niccolini-sipping-siphandover-03
>>>
>>> [2] A solution for vertical handover of multimedia sessions using SIP 
>>> http://tools.ietf.org/html/draft-salsano-sipping-siphandover-solution-02
>>>
>>> Now I would like in particular to focus on the requirements draft [1] 
>>> and to make some comparison with your work.
>>>
>>> It seems that the requirements and scenarios we consider are largely
>>> overlapping (while we take different approaches for solutions).
>>>
>>> We have in common the idea of letting the Correspondant Node as much as
>>> possible not involved in the seamless handover procedure and the
>>> introduction of some sort of B2BUA to assist in the procedure. We also
>>> share the idea that bi-casting can improve the handover and needs to be
>>> properly managed.
>>>
>>> As you have already outlined in your draft, a difference in the
>>> requirements is that you would like not to introduce new
>>> headers/parameters while we allow it.
>>>
>>> My point here is that the introduction of the new headers in our
>>> scenario only concerns the handover-capable mobile device and the
>>> intermediate element which is in charge to assist in the handover
>>> procedure. Correspondant Node and all other SIP elements are not touched
>>> anyhow. I feel that in any case there the need to implement a lot of
>>> specicif logic to properly handle the bi-casting (not to mention the
>>> problem of discovery of intermediate element that you deliberately
>>> neglect in your draft to simplify the problem). Therefore the addition
>>> of a new header may not be the biggest issue.
>>>
>>> Anyway these aspects could be clarified with some deeper technical
>>> discussion, which I hope can start in the WG.
>>>
>>> Best regards,
>>> Stefano
>>>
>>> Haruki Izumikawa wrote:
>>>> Hello folks,
>>>>
>>>> I'd like to have an open discussion about SIP-based mobility in this 
>>>> ML.
>>>> Mobility managements using SIP have been actively studied and developed
>>>> worldwide since "Mobility Support Using SIP" (by Elin and Henning) was
>>>> published. SIP-based mobility would have strong advantages such as its
>>>> great affinity for an application as well as flexibility, i.e., 
>>>> terminal
>>>> mobility can be optimally supported independent from underlying 
>>>> network.
>>>> On the other hand, despite many advantages, it is not used for
>>>> large-scale commercial yet. In addition, the discussion about SIP-based
>>>> mobility in IETF seems to be undynamic.
>>>> These days, a multimode terminal is getting popular. Each access
>>>> networks, e.g., cellular and WLAN, have different characteristics in
>>>> terms of throughput or delay. In such a heterogeneous network, SIP
>>>> becomes more useful tool for mobility management because of its
>>>> flexibility. The quality of a multimedia service can be adaptively
>>>> changed in accordance with a nature of an access networks even after
>>>> changing an access network. I think it is time to resume discussing
>>>> about SIP-based mobility. For your information, I have submitted I-D
>>>> regarding seamless session handoff by SIP-based bicasting.
>>>> http://www.ietf.org/internet-drafts/draft-izumikawa-sipping-sipbicast-01.txt 
>>>>
>>>> I would be happy to hear frank opinions of SIP specialists.
>>>>
>>>> Best regards,
>>>>
>>>> Haruki
>>>>
>>>>
>>>
>>
> 

-- 
Haruki Izumikawa
KDDI R&D Laboratories

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