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?
> >
> >+-----------------------------------------------------------------+
> >
>