I also think it's a valuable capability.  

Brian

On Jan 18, 2012, at 12:22 PM, <[email protected]> wrote:

> 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
>>>>> 
>>> 
>>> 
> 
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