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Re: [802.21] Discussion on Information Service



Hi Qiaobing,

Regarding the last question, I can answer in the following way:

- Providing other network related information to upper layers can also
be supported by higher-layer mechanism/protocols.  However, we cannot
rely *solely* on higher-layer mechanism/protocols as the information
would need to be obtained even before establishing IP connectivity.
(i.e., IETF does not cover all use cases of the 802.21 information
service).

- Providing other network related information to upper layers using
link-layer specific mechanism may end up with each link-layer to
define its own way fo carrying the information.  802.21 will simplify
each link-layer by defining media-independent way of carrying other
network related information that can work across different
link-layers.

Yoshihiro Ohba


On Sun, Aug 21, 2005 at 04:22:12PM -0500, Qiaobing Xie wrote:
> All,
> 
> I think this discussion is very important at this point. Indeed, we have 
> talked about the scope and other issues before (a lot), but for one I am 
> not 100% satisfied with what we have concluded. I have also heard from 
> multiple sources outside of 802.21 that the current scope of 802.21 is 
> both too big and ambiguously defined. For example,
> 
>     - provide generic link layer intelligence and other network
>       related info to upper layers to optimize handovers between
>       heterogeneous media
> 
> It is easy to argue that 802.21 is in a good position to provide generic 
> link layer intelligence to upper layers for handover. But for providing 
> "other network related info to upper layers" for handover, I am not so 
> sure. People can rightly question why we think 802.21 is better suited 
> than other mechanisms/protocols in providing network info to upper 
> layers for optimizing handover.
> 
> regards,
> -Qiaobing
> 
> Koora Kalyan Com Bocholt wrote:
> >Hello All,
> >
> >after taking part in couple of telcons, I feel that there is a 
> >strong need to raise a disucussion on the .21 Information Service.
> >In particular I feel that there is an urgent need to fix the basic
> >information set at this point before proceeding to different
> >standardisation bodies.
> >
> >As a starting point, I am just putting couple of basic points 
> >together to have a common understanding in discussion.
> >I would be happy to see your comments/opinions/ideas/suggestions
> >to reach a common consensus on this matter.
> >
> >with best regards,
> >Kalyan Koora
> >
> >+-----------------------------------------------------------------+
> >|                Discussion on Information Service                | 
> >+-----------------------------------------------------------------+
> >
> >I.   What is 802.21 MIH scope?
> >II.  Handover of what?
> >III. Present Handover mechanisms
> >IV.  How to continue?
> >
> >I. What is 802.21 MIH scope?
> >
> >   - provide generic link layer intelligence and other network 
> >     related info to upper layers to optimize handovers between 
> >     heterogeneous media
> >
> >   - enhance and/or support handovers between heterogeneous 
> >     media
> >
> >   - maximize service continuity
> >
> >II. Handover of what?
> >
> >  - A session / an application running over a media to other media
> >
> >  - session/service continuity is desired
> >
> >  If we are speaking about a "session", then we mean 
> >  "running application".
> >
> >  If we are speaking about "handover of a running session" from 
> >  one to other media, it is a "must" that the minimum requirements 
> >  of the session are available at the other media.
> >
> >III. Present Handover mechanisms
> >   Present well known handover mechanisms (like MIP):
> >   - select one media for all sessions
> >   - do not do load-balancing
> >   - neither care about application needs nor take care of
> >     user or network preferences dynamically
> > 
> >  The evolving mechanisms are aiming to enable this.
> >  To assist these intelligent handover mechanis (what 802.21 is
> >  aiming at), it is important to have following information 
> >  as early as possible:
> >
> >  1. what applications are running on the terminal or what
> >     sessions are build up
> >  2. If a new session/application is started, what are its needs
> >  3. what medias are present in the terminal and what are their
> >     capabilities
> >  4. what are the reachable networks in the vicinity and
> >     what are their capabilities.
> >  5. what application support is provided by the networks
> >  6. Last but most, what are the user and operator preferences.
> >
> >  If these points are agreed, then comes the question:
> >  Taking the above mentioned points into consideration, if 802.21 
> >  likes to enhance the handover mechanisms, what is the 
> >  information envisaged by the .21?
> >
> >IV. How to continue:  
> >   
> >   To refine/enhance/modify I feel, there is an urgent need to
> >   take a look at the IS, in particular the basic set.
> >
> >   What is needed?
> >
> >   - shall we define a unique basic set for all standards, to be
> >     media independent?
> >   
> >   - shall we take the existing basic set, think of scenarios
> >     where this is needed and put them as essential and remove
> >     the things which are not needed?
> >
> >   - shall we define completely new set for each and every standard
> >     just like independent SAPs?
> >   
> >+-----------------------------------------------------------------+
> >
>