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Re: [HOME_NETWORK_TF] Comments on "Application Communication" requirement

From: Giuseppe Pascale <giuseppep@opera.com>
Date: Mon, 29 Aug 2011 12:15:02 +0200
To: "Jean-Claude Dufourd" <jean-claude.dufourd@telecom-paristech.fr>, "public-web-and-tv@w3.org" <public-web-and-tv@w3.org>, "Bob Lund" <B.Lund@cablelabs.com>, "Matt Hammond" <matt.hammond@rd.bbc.co.uk>
Message-ID: <op.v0yz3cph6ugkrk@laptop>
On Mon, 29 Aug 2011 11:59:30 +0200, Matt Hammond <matt.hammond@rd.bbc.co.uk> wrote:

> I think you are right - this needs separating into two requirements.
>
> I believe that what Bob originally suggested regarding "discovery" might
> apply "application communication" too.  For example:
>
> "Application communication: Conforming specifications should provide a
> means for applications running in different user-agents to discover each
> other and exchange messages directly via the home network."
>
>
There is a separate section/requirement for discovery.
As is phrased now the requirement about discovery mention both services and "application exposing services":

http://www.w3.org/2011/webtv/wiki/HNTF/Home_Network_TF_Requirements#Service_Discovery

***
Service Discovery:
Conforming specifications should provide a means for applications to discover devices and applications in the home network which advertise services. Details of the advertising protocol are out of scope for this document and the type and number of supported discovery protocols are user agent dependent. Nevertheless conforming specifications should provide a means for application to identify the type of discovered services that are available and to search for services of a specific type.
***

I think is just a matter of semantics here: is an application that is discoverable implicitly "exposing a service"? If so, then we may not need a new requirement; if not, we may want to separate discovery/communication of applications from discovery/communication of services.

Honestly I don't have a strong opinion.  One reason why we may want to split this in 2 requirements could be that app-2-app discovery and communication could probably generate slightly different requirements if compared to app-2-service discovery & communication when going into the actual specification work.

In short I see 2 options:
#1 we keep the requirement as quote above
#2 we add to the requirement above another one that could look like this:

***
Application Discovery:
Conforming specifications should provide a means for applications running in different user-agents to discover each other directly via the home network. Details of the advertising protocol are out of scope for this document.
***

I would propose to go for option #2.

/g

>
> many thanks
>
>
>
> Matt
>
>
> On Sun, 28 Aug 2011 23:31:05 +0100, Giuseppe Pascale <giuseppep@opera.com>
> wrote:
>
>> On Sun, 28 Aug 2011 21:49:33 +0200, Matt Hammond
>> <matt.hammond@rd.bbc.co.uk> wrote:
>>
>>> Definitely agree with Bob that this requirement should be expressed in
>>> terms of how there needs to be discovery in order to initiate
>>> communication.
>>>
>>> Thinking about the use of the term 'services': should this be phrased
>>> in terms of 'applications' throughout, rather than 'services'?
>>> Communication with services is already covered by other requirements.
>>> This particular requirement originated from the "Local Link for Web
>>> Applications" use case[1]:
>>>
>>> http://www.w3.org/2011/webtv/wiki/HNTF/Home_Network_TF_Requirements#U14:_Local_Link_of_Web_Applications
>>>
>>
>> Agree. It seems to me we need 2 requirements. We can leave the one about
>> "service communication" as phrased below, plus I would add the following:
>>
>> "Application communication: Conforming specifications should provide a
>> means for applications running in different user-agents to exchange
>> messages directly via the home network."
>>
>> Bob, Matt, what do you think?
>>
>> /g
>>
>>> regards
>>>
>>>
>>> Matt
>>>
>>> On Tue, 23 Aug 2011 16:08:04 +0100, Giuseppe Pascale
>>> <giuseppep@opera.com> wrote:
>>>
>>>> On Mon, 22 Aug 2011 18:13:38 +0200, Bob Lund <B.Lund@cablelabs.com>
>>>> wrote:
>>>>
>>>>> I agree but I think it should be stated in terms of access to
>>>>> services discovered on the home network:
>>>>>
>>>>> "Service communication: Conforming specifications should provide a
>>>>> means for a client to exchange messages directly via the home network
>>>>> with services discovered in the home network."
>>>>>
>>>> As discussed I changed this into
>>>>
>>>> "Service communication: Conforming specifications should provide a
>>>> means for an application to exchange messages directly via the home
>>>> network with services discovered in the home network."
>>>>
>>>> http://www.w3.org/2011/webtv/wiki/HNTF/Home_Network_TF_Requirements#Service_communication
>>>>
>>>> /g
>>>>
>>>>> Bob
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: public-web-and-tv-request@w3.org [mailto:public-web-and-tv-
>>>>>> request@w3.org] On Behalf Of Jean-Claude Dufourd
>>>>>> Sent: Monday, August 22, 2011 9:05 AM
>>>>>> To: public-web-and-tv@w3.org
>>>>>> Subject: Re: [HOME_NETWORK_TF] Comments on "Application
>>>>>> Communication"
>>>>>> requirement
>>>>>>
>>>>>> I strongly support this clarification about direct communication.
>>>>>> Best regards
>>>>>> JC
>>>>>>
>>>>>> On 22/8/11 16:44 , Giuseppe Pascale wrote:
>>>>>> > On Sun, 21 Aug 2011 20:20:43 +0200, Matt Hammond
>>>>>> > <matt.hammond@rd.bbc.co.uk> wrote:
>>>>>> >
>>>>>> >> Hi all,
>>>>>> >>
>>>>>> >> Apologies for this being a little later than I originally
>>>>>> intended:
>>>>>> >> as I mentioned in last week's conf call, I have a comment
>>>>>> regarding
>>>>>> >> the "Application Communication" requirement.
>>>>>> >>
>>>>>> >> Would it be helpful to clarify that this requirement is
>>>>>> specifically
>>>>>> >> intended to enable direct communication between applications? This
>>>>>> >> would be to distinguish it from an implementation that (for
>>>>>> example)
>>>>>> >> sent all communications through a cloud based relay or proxying
>>>>>> service?
>>>>>> >>
>>>>>> >> For example: "Conforming specifications should provide a means for
>>>>>> >> applications to exchange messages directly via the home network
>>>>>> with
>>>>>> >> other applications running on a different user agent in the home
>>>>>> >> network."
>>>>>> >>
>>>>>> >
>>>>>> > Hi Matt,
>>>>>> > thanks for raising this in writing.
>>>>>> > I agree that several (all?) of the use cases we have discussed
>>>>>> require
>>>>>> > (preferably) a direct communication. I think this is pretty
>>>>>> > uncontroversial and could add it right away to the requirement
>>>>>> document.
>>>>>> > Some of the use cases could actually be covered by an indirect
>>>>>> > communication mechanism as well, so probably also that would be in
>>>>>> > scope. On other end such a mechanism may either not need
>>>>>> (additional)
>>>>>> > standardization or fall back to the a different discussion about
>>>>>> which
>>>>>> > services could be standardized.
>>>>>> >
>>>>>> > So in short I'm fine to re-word the requirement as you suggested if
>>>>>> > nobody objects.
>>>>>> >
>>>>>> > /g
>>>>>> >
>>>>>> >> regards
>>>>>> >>
>>>>>> >>
>>>>>> >>
>>>>>> >> Matt
>>>>>> >
>>>>>> >
>>>>>>
>>>>>>
>>>>>> --
>>>>>> JC Dufourd
>>>>>> Directeur d'Etudes/Professor
>>>>>> Groupe Multimedia/Multimedia Group
>>>>>> Traitement du Signal et Images/Signal and Image Processing Telecom
>>>>>> ParisTech, 37-39 rue Dareau, 75014 Paris, France
>>>>>> Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>


-- 
Giuseppe Pascale
TV & Connected Devices
Opera Software - Sweden
Received on Monday, 29 August 2011 10:15:45 UTC

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