Re: [802.21] [Mipshop] Re: Architectural Considerations for Handover InformationServices (was: Re: CARD Discussion Query Discussion)
Please see my comments inline...
> From: Yoshihiro Ohba <yohba@TARI.TOSHIBA.COM>
> Reply-To: Yoshihiro Ohba <yohba@TARI.TOSHIBA.COM>
> Date: Sun, 16 Oct 2005 00:04:11 -0400
> To: <STDS-802-21@listserv.ieee.org>
> Subject: Re: [802.21] [Mipshop] Re: Architectural Considerations for Handover
> InformationServices (was: Re: CARD Discussion Query Discussion)
>
> On Sat, Oct 15, 2005 at 11:22:02PM -0400, Singh Ajoy-ASINGH1 wrote:
>> Several comments:
>>
>> - Informaiton encoding is one design factor, but we should think more
>> about other factors such as extensibility, flexibility, and actual
>> volume of encoded contents (regardless of how it is encoded).
>>
>> Ajoy-> Sure, what makes you think that size of XML encoded message will
>> be smaller than TLV encoded message? TLV can be extensible and flexible
>> as well.
>> TLV encoding is used by very successful protocol such as L2TP that is
>> highly deployed and highly extensible as well.
>
> I am not claiming that the size of XML encoded message will be smaller
> than TLV encoded one.
>
> I am claiming that if Solution 1 that provides less semantic query
> (one may call it simple query) needs to carry x1 bytes of actual
> information with its encoding overhead o1 bytes, while Solution 2 that
> provides more semantic query (one may call it complex query) needs to
> carry x2 (<x1) bytes of actual information with its encoding overhead
> o2 (> o1) bytes, to make the same handover decision, then what we need
> to compare in terms of information volume is [x1+o1 vs. x2+o2],
> instead of [x1 vs. x2] or [o1 vs. o2]. And when we are discussing
> information encoding, we are just discussing [o1 vs. o2], and choosing
> a solution based only on this factor is wrong.
>
> If we view Solution 1 as TLV-based and Solution 2 as XML-based, then I
> think [x1 > x2] && [o1 < o2], and depending on how we encode XML,
> diffence between o1 and o2 can be small.
>
[hong-yon] I think your analysis is misleading. First of all, why semantic
query cannot be carried out with TLV encoding? TLV has been used to convey
flexible payloads, which can be of different combination of information
elements. One example is the optional fields; another is that different
information elements have their identifiers to allow them to be flexibly
selected for exchange on a per-need (semantic) basis. Thus, there is no
reason that x1 and x2 are different! Besides, in the overheads, there is
more than just information encoding, there is also the information
structure.
>>
>> - In reality, 3GPP2 has XML-based method (e.g., XCAP) in its
>> dependency list.
>>
>> Ajoy-> OK, I think it will be good to know if XML is being recommended
>> by of cellular standards for control plane signaling or handover related
>> signaling.
>
> Also note that real-time requirement for IS is relatively less critical
> than ES and CS.
>
> Yoshihiro Ohba
>
>>
>>
>> Yoshihiro Ohba
>>
>>
>>
>> On Fri, Oct 14, 2005 at 06:19:26PM -0400, Singh Ajoy-ASINGH1 wrote:
>>> But it does not seem to be true given the current discussion.
>>>
>>>
>>>
>>> Ajoy-> In IETF folks are trying to help 802.21 to get the work done
>>> better.
>>>
>>> I do not believe there is anything wrong if some folks do not agree
>> with
>>> XML query. Honestly I do not believe XML query is good for low power
>>>
>>> mobile devices. Based upon our current experience folks are finding
>> hard
>>> to cope up with SIP and SIP compression itself. It looks good on
>> paper,
>>>
>>> but somehow when you implement compression you may find that delay
>>> introduced by compression out performs the bandwidth saving gained
>> from
>>>
>>> compression. I do not believe that adding one more level of
>> compression
>>> for XML will be better idea.
>>>
>>> As a research topic it may look very attractive, but we have to look
>> at
>>> today's reality. I would like to state that in one of my discussions
>>>
>>> I suggested that even TLV encoding can be modified to carry XML script
>>> to address some use cases where XML may be a good choice.
>>>
>>> I am afraid we are trying to push XML without considering reality at
>>> hand.
>>>
>>>
>>>
>>> Also, what is wrong about sharing view of 802.21 when MIPSHOP is going
>>> to define a protocol that would cater need of
>>>
>>> 802.21 itself?
>>>
>>>
>>>
>>> Nothing wrong in sharing the view. But do we need to mention the
>> straw
>>> poll result to establish our technical reasoning?
>>>
>>>
>>>
>>> Ajoy-> Perhaps you did not like the word straw poll. I will make note
>>> of that. I think enough reasoning was given to justify that
>>>
>>> XML query complex query may not be good for low power mobile devices.
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>