Re: [802.21] question on MIH event subscription
On Mon, Mar 05, 2007 at 02:12:23PM -0600, Qiaobing Xie wrote:
>
> >
> > So I guess you are talking about multiple MIH users on the IS server
> > side. But, I don't see a need for handling multiple MIH IS users on
> > the IS server, which makes me think that event subscription is not
> > needed to receive MIH_Get_Information.indication.
>
> It is still possible that we will face the same dispatching problem on
> the IS server side, since you may have multiple MIH Users above the
> MIHF, with one of them the IS server application. Keep in mind that an
> MIHF is supposed to have no knowledge of the type of application of a
> particular MIH User, i.e., to the MIHF all MIH Users above look the same
> and it has no way to know whether a given MIH User is an IS server or not.
This is an interesting point.
>
> So the MIHF will still need a way to know which MIH User(s) should
> receive an MIH_Get_Information.indication when the MIHF receives an
> MIH_Get_Information Request message. *When we write the spec*, the most
> elegant and clean way is to just follow the same consistent event
> subscribe/notify model. Inside your implementation, however, you can
> always choose to code the subscription as an default behavior which
> happens implicitly when you IS server application starts.
In general, I think what we need here is a mechanism for MIH Users to
register a set of indication-type primitives with the local MIHF, just
like registering a set of functions with OS when initializing a
driver.
This seems to be a different problem than event subscription. Said
that, use of event subscription may not be a cleaner approach.
Also, is this really a specification issue or an implementation issue?
Yoshihiro Ohba
>
> regards,
> -Qiaobing
>
> >
> > What do you think?
> >
> > Yoshihiro Ohba
> >
> >
> > On Mon, Mar 05, 2007 at 01:11:54PM -0600, Qiaobing Xie wrote:
> >> Hi, Yoshi,
> >>
> >> I would think so. On the surface it may seems to be an inconvenience
> >> (one more step for the IS client). However, if you think about the
> >> actual implementation, it is a big help:
> >>
> >> - You (as the local MIHF) generate a MIH_Get_Information.indication when
> >> you receive a MIH_Get_Information response from a peer MIHF.
> >>
> >> - If you only have one MIH User above you, it is quite simple - you
> >> invoke the MIH_Get_Information.indication to that MIH User.
> >>
> >> - But it becomes interesting if you have more than one MIH Users above
> >> you. You have the following options:
> >> 1) invoke a separate MIH_Get_Information.indication to each one of
> >> them. But this could be very unnecessary since some of your MIH Users
> >> may have nothing to do with Info Service.
> >> 2) invoke the MIH_Get_Information.indication to the MIH User who
> >> originally initiated the IS query - this is a much better design. The
> >> only limitation is that you will not be able to have one MIH User as the
> >> querier and different MIH User as the IS response handler.
> >> 3) use event subscription and only invoke
> >> MIH_Get_Information.indication to whichever MIH User(s) who has
> >> subscribed the event.
> >>
> >> To me 1) is unacceptable, 2) is ok, 3) is both efficient and flexible
> >> and consistent with event subscription/notify model.
> >>
> >> And we really want, we can even combine 2) and 3) - if no one subscribes
> >> the event, then we dispatch a MIH_Get_Information.indication to the
> >> original querier.
> >>
> >> regards,
> >> -Qiaobing
> >>
> >> Yoshihiro Ohba wrote:
> >>> Hi Qiaobing,
> >>>
> >>> I am a slow starter to follow this thread :)
> >>>
> >>> What about MIH_Get_Information indication for Information Service? Is
> >>> it also considered as an MIH event and event subscription is needed
> >>> for it?
> >>>
> >>> Yoshihiro Ohba
> >>>
> >>>
> >>> On Thu, Mar 01, 2007 at 11:40:22AM -0600, Qiaobing Xie wrote:
> >>>> All,
> >>>>
> >>>> I think the following statements should be true:
> >>>>
> >>>> - any MIH .indication primitive shall be considered an MIH event
> >>>> - an MIH User shall be notified about an MIH event only that User has
> >>>> explicit subscription for the event
> >>>>
> >>>> Therefore, we will need to accept the following scenario as perfectly
> >>>> normal:
> >>>>
> >>>> 1. An MIH User invokes MIH_Configure_Link and sets some threshold in
> >>>> order to get a link report when that threshold is crossed;
> >>>>
> >>>> 2. But he forgets to (or intentionally does not) explicitly subscribe
> >>>> MIH_Link_Parameters_Report.indication event;
> >>>>
> >>>> 3. When the event happens, the User will not get the indication.
> >>>>
> >>>> My reasoning is that one may want to build a User whose responsibility
> >>>> is just to set link thresholds but the responsibility for receiving and
> >>>> processing the events are delegated to a different User (or Users). The
> >>>> latter will subscribe for the event but not the former.
> >>>>
> >>>> regards,
> >>>> -Qiaobing
> >>>>
> >
>