HNTF/Home Network TF Discussions/ServiceDistribution

From Web and TV IG

Service Distribution

Submitter: Jean-Claude Dufourd, Telecom ParisTech

Tracker Issue ID: ISSUE-8

Description: An application spawning other applications on other devices and communicating with them: e.g. the TV set receives and renders an application implementing some voting; the application discovers multiple phones in the home, proposes to activate voting interfaces on each of the viewers' phones, communicates with the voting interfaces, collates votes and sends them back to the channel's voting service.


  • The TV receives a connected TV application for voting, which starts automatically.
  • The application exposes a service on the HN to collect votes and forward them to the TV channel.
  • The application discovers personal interactive devices (phones and tablets for our case) running the HNTF document UA which exposes a recognizable service.
  • The application sends a suggest message with a URL to a voting interface.
  • Willing users accept the suggested migration and their UA loads the voting interface.
  • The voting interface document loads and discovers and binds to the vote collecting service.
  • The user votes
  • The voting interface document sends a vote message to the vote collecting service.
  • The vote collecting service exposed by the TV application receives the vote message and forwards them for a certain voting period.
  • At the end of the show (or of the voting period), the application is killed by the TV system, so the voting collection service disappears.
  • Seeing the voting collection service disappear, the voting interfaces may shut down.

This use case does not require new technology, but reuses technology required by other use cases. Technologies required by other use cases are:

  • the ability to discover
  • the ability to expose a service

This use case requires:

  • the HNTF UAs to implement a service which could be called "HNTF service", so that documents can discover other "HNTF UAs"
  • the HNTF service to include a "suggest" message telling the UA to please render a document given by URL
  • maybe the HNTF service to include a message allowing a document to determine its capabilities, to be able to segregate between devices appropriate for voting or not.

A few sketches for clarification:


This is the generic version of a crucial "second screen" usage scenario.

As there are more devices in the home, some generic and some task-specific, and with varying capabilities (including different UI methods), there is a growing need to spread an application across different devices to achieve service distribution. But the service usually "enters" the home network through one particular device. The service running entirely on the initial device, as part of other use cases, can discover its environment and determine that other devices could meaningfully contribute to the quality of experience. From then on, the service needs to send part of "itself" to other devices. Hence this use case.

Dependencies: Depends on Service UI, Document Responding to Requests, Document Exposing a Service, Document Discovering a Service