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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.

> 
> - 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. 
> > 
> >  
> > 
> >  
> > 
> >  
> 
>