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RE: Extending Network Service Discovery draft with advertisement

From: Jan Lindquist <jan.lindquist@ericsson.com>
Date: Mon, 12 Mar 2012 16:02:54 +0100
To: Bryan Sullivan <blsaws@gmail.com>, Rich Tibbett <richt@opera.com>
CC: Clarke Stevens <c.stevens@cablelabs.com>, "public-device-apis@w3.org" <public-device-apis@w3.org>
Message-ID: <82276AE38FD87A4C9CF6C820AC5276EA36D953E06E@ESESSCMS0362.eemea.ericsson.se>
Hi Rich,

Bryan did a good job in expanding on the examples. If we agree in the general use case we can work on the details of how the API's may look like to support the "registration" of these services that want to be shared in the home.

The one additional aspect to the use case is that there is no "middle man" to provide communication between the two applications. Below is the "Depencencies" requirements:
"This is a prerequisite to applications discovering each other without a "middle man": one of the two applications exposes a service that the other application may discover."

The tricky part is the security and privacy aspects of this advertisement of the service. Here I suggest to do an interation of proposals from the requirements to see see if there is a ideal solution. This step can be done with some demos to better understand the solution. I would be concerned to jump too quickly on those aspects before getting an agreement on base requirements to analyze the alternatives.


> -----Original Message-----
> From: Bryan Sullivan [mailto:blsaws@gmail.com] 
> Sent: den 12 mars 2012 14:37
> To: Rich Tibbett
> Cc: Jan Lindquist; Clarke Stevens; public-device-apis@w3.org
> Subject: Re: Extending Network Service Discovery draft with 
> advertisement
> Rich, as below the referenced req doc describes the use case 
> pretty well, but perhaps we can dive a little deeper e.g. if 
> someone has a demo that they've done re something similar we 
> can get a few more details as to how that was done.
> The protocol handler registration of HTML5 (and also content 
> hander, both are addressed by
> http://www.w3.org/TR/html5/timers.html#custom-handlers) is a 
> specific exposure approach based upon advertisement of a URL 
> scheme or MIME type handler capability by a website, via the 
> registerContentHandler() method. In the use case below, how 
> do you think this website
> (HTML+Javascript) content from the advertising device could 
> get to the other devices in the HN, so that it could 
> advertise itself? Would all the discovering devices have to 
> browse to all the other devices somehow, or is there an 
> automated way to make this happen under HTML5's API for this?
> From: 
> http://www.w3.org/TR/2011/NOTE-hnreq-20111201/#u6.-application
> -exposing-a-service
> "An application exposes a service on the home network. In 
> order to allow this with some technologies, it may be 
> necessary for the HNTF user agent to advertise itself on the 
> HN as a device. For example, an application rendered on a 
> connected TV has access to the connected TV API for EPG 
> information. Other devices on the HN do not have access to 
> this information. The application implements a service 
> exposing the EPG information and makes it discoverable by 
> other devices.
> Possible implementation:
> the application A is a TV-broadcast-related application, 
> which is allowed to call the function returning the 
> description of the next program.
> the application A exposes a service with one message 
> getNextProgramDescription.
> application B on another device discovers the service (not 
> knowing that it is an application, it is just another service 
> to application B).
> Neither application A or B know the actual nature of the 
> other. They may have an IP address, and they share a service type."
> On Mon, Mar 12, 2012 at 7:27 AM, Rich Tibbett <richt@opera.com> wrote:
> > Jan Lindquist wrote:
> >>
> >> Hi,
> >> Even though this is only a draft I would like to suggest to extend 
> >> the draft "Network Service Discovery and Messaging" with 
> >> advertisement support.
> >> Reference to original draft
> >> 
> _http://people.opera.com/richt/release/specs/discovery/Overview.html_
> >> The proposal is to update section 9 Use Cases and 
> Requirements with a 
> >> new requirement that is in line with the requirement specified in 
> >> published "Requirements for Home Network Scenarios".
> >> Reference to published requirements
> >> _http://www.w3.org/TR/2011/NOTE-hnreq-20111201/_
> >> The requirements to be added are according to the following two 
> >> sections 1. 
> >> 
> _http://www.w3.org/TR/2011/NOTE-hnreq-20111201/#services-advertisemen
> >> t_
> >> 2.
> >>
> >> 
> _http://www.w3.org/TR/2011/NOTE-hnreq-20111201/#u6.-application-expos
> >> ing-a-service_ If this is agreed then I will contribute with the 
> >> necessary changes to provide the support.
> >
> >
> > Perhaps you could describe in more detail the use case 
> here? Is this 
> > about web apps advertising themselves as Local Network 
> Services? That 
> > is something I'd particularly like to see proposals for so please 
> > forward them here and we can discuss them further. For the 
> most part 
> > that's something that I see registerProtocolHandler doing [1].
> >
> > Best regards,
> >
> > Rich
> >
> > [1]
> > 
> http://www.whatwg.org/specs/web-apps/current-work/multipage/timers.htm
> > l#dom-navigator-registerprotocolhandler
> >
> --
> Thanks,
> Bryan Sullivan
Received on Monday, 12 March 2012 15:03:27 UTC

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