A clarification with regard to the need for push notifications. I am not aware that this is an Ofcom requirement. In their last consultation Ofcom's description of a master device says that it must "cease transmission immediately where the time validity expires or where it moves outside of the geographic area of validity". The master polls every x hours (e.g. every two hours), using a periodicity set by regulation, in order to maintain validity for the TVWS channel it is using, and does not need to be able to receive pushed information. This works because any changes to channel availability (due to a local news event requiring wireless microphones for example) have a lead time, which give the opportunity for the channel to be cleared. Microphones needing to be operational more quickly than x hours could be operated in other spectrum (for example). The same process would enable a network to be turned off within x hours if Ofcom so desired.
Having said that, I am in favour of there being a push capability from the database to masters. I just think it would not be implemented by all masters if not required the regulator, so would be optional. Regards Andy -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 18 January 2012 16:51 To: [email protected] Cc: [email protected] Subject: Re: [paws] next steps for the wg An example: A white space database may decide to withdraw channels that were previously indicated as being available for use to a set of master devices (reason being a need for those channels by some emergency service). Devices register with the database as part of the initial authentication/authorization process and hence the database would have the capability of sending such messages only to the relevant devices and not to all devices. It does result in state being maintained at the database. The requirement for such capability is needed by Ofcom (AFAIK) and hence the proposal. Solutions will need to consider how to deal with this optimally. -Raj On 1/18/12 10:43 AM, "ext Joel M. Halpern" <[email protected]> wrote: >Sorry to be slow. >How does the database know which changes are of interest to any >particular registered client? I would hope that it does not push all >changes to all clients. But i not, it needs to somehow guess which >changes matter. Would it keep track of what answers it has sent to >each such registered clients, and try to track which changes may affect >actions of that client? > >Yours, >Joel > >On 1/18/2012 11:38 AM, [email protected] wrote: >> >> Hi Joel, >> >> The proposal to include unsolicited Push notifications from the white >>space database to a master device is different from the >>Request/Response mechanism itself. >> A master device making a request for available channels expects a >>response in some time window. Not proposing we change that. >> However the white space database knows of devices which have >>registered with it. And hence can send push notifications at will >>without necessarily having to react to a request. >> >> -Raj >> >> On 1/17/12 8:03 PM, "ext Joel M. Halpern"<[email protected]> wrote: >> >>> While responses have time windows, as far as I know, requests do not >>> specify when the response will be acted upon, if ever, or for how long. >>> >>> As such, this seems to imply either that we add significantly more >>> information to requests, or that any change in anything that has >>> ever been asked for gets pushed? >>> That does not sound like a good design. >>> >>> Yours, >>> Joel >>> >>> On 1/17/2012 6:08 PM, [email protected] wrote: >>>> >>>> Hi Gabor, >>>> >>>> On 1/12/12 8:26 PM, "ext >>>> [email protected]"<[email protected]> >>>> wrote: >>>> >>>>> P.3 currently says: The protocol between the master device and >>>>>the WS Database MUST support pushing updates in channel >>>>>availability changes to subjects. >>>>> There were comments that this requirement involves a mechanism, we >>>>>should reformulate to be mechanism agnostic. >>>>> There was a suggestion to "make the requirement "quick way to >>>>>change availability" rather than imply a mechanism.". >>>>> The use case is that if the channel availability changes in the >>>>>DB, the client has to be able to detect it and get the new >>>>>availability list within a time period set by the regulator. >>>>> Can someone send suggested text on how to reformulate this >>>>>requirement? >>>> >>>> The requirement to enable Push notifications to be sent to a white >>>>space device which has registered with a database is important >>>>especially in the context of Ofcom requirements (I believe). The >>>>reasons for such push notifications could be for purposes that go >>>>beyond just channel availability updates. A proposal for the >>>>requirement is as follows: >>>> >>>> Requirement: A white space database should be able to send >>>> unsolicited messages to a master device which has registered with >>>> it. The protocol between the WS database and master device MUST >>>> allow for push notifications to be sent from the database to the master >>>> device. >>>> >>>> -Raj >>>> >>>> _______________________________________________ >>>> paws mailing list >>>> [email protected] >>>> https://www.ietf.org/mailman/listinfo/paws >>>> >> >> _______________________________________________ paws mailing list [email protected] https://www.ietf.org/mailman/listinfo/paws _______________________________________________ paws mailing list [email protected] https://www.ietf.org/mailman/listinfo/paws
