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Re: Extending Network Service Discovery draft with advertisement

From: Dave Raggett <dsr@w3.org>
Date: Mon, 12 Mar 2012 14:22:36 +0000
Message-ID: <4F5E06AC.6000006@w3.org>
To: public-device-apis@w3.org
On 12/03/12 12:27, Rich Tibbett wrote:

> 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.html#dom-navigator-registerprotocolhandler


Something I've thought about is locally installed web apps that act as
multiplayer games, and where the game players are all on the same local
network. You need some way to locate other game players, and an
efficient means to communicate with them.

Multicast messaging seems very promising for this purpose, firstly as a
means to advertise your readiness to play, and secondly as an efficient
means to distribute events to all players. In practice, multicast
messages are limited in length, but present no problem for modest sized
JSON encoded events.

To avoid security problems, you would limit the multicast port range and
impose checks on the messages. The users would first need to give their
consent.  We don't need to limit discovery to UPnP!

A further idea was to look at privacy friendly local discovery, given
that multicast packets can typically be read by anyone on the same LAN.
Sometimes you might care about who can see which devices/services are
being advertised. The advertisements are encrypted to ensure that only
intended parties can read them. This is a bit like DRM in that you need
careful key management.

-- 
Dave Raggett <dsr@w3.org> http://www.w3.org/People/Raggett
Received on Monday, 12 March 2012 14:23:05 UTC

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