1 Motivation
In their conversion to digital television, cable television systems in many countries are also provisioning very high-speed bidirectional data facilities intended to support, among other payloads, those utilizing Internet Protocols (IP). These facilities can also be used to supply other digital services to the home, based on packet-data, exploiting the broadband capacity provided by hybrid fibre/coaxial (HFC) digital cable television systems, and interconnecting local, geographically distinct digital cable television systems through direct connections or managed backbones.
The envisaged range of packet-based data services to be provided encompasses those services and applications that are based on the use of IP. It also encompasses among others, digital bidirectional (interactive) television and sound-programme cablecasting, advanced interactive television, sound-programme and multimedia services, video conference and video telephony down to the emulation of some services that are now normally provided over the public switched telephone network
(PSTN).
The technology considered for the delivery of those packet-based data services over the cable television infrastructure resorts to the use of the relevant transmission protocols, including Internet Protocols (IP) and enhancements thereof.
The peculiarities common to the range of services to be provided are:
- the use of modern hybrid bidirectional fibre/coax television cable networks;
- the use of the transmission methods specified for those networks;
- the use of the architecture and modems specified for those networks;
- compliance with the specifications and QoS peculiar to those networks;
- capability for real time (low latency) operation for interactive services that require it;
- interoperability with relevant transmission protocols for packet-based data, notably IP protocols;
- a performance level that is equal to or better than the one provided by the PSTN, for telephone-type services.
2 Question
- What are the services that could desirably be provided over the digital cable television infrastructure, by means of packet-based data transmission?
- What are the functionalities that each service should be capable to provide in order to meet its service requirements?
- Which open protocols can be used for the envisaged services, preferably choosing them among those already recommended for packet-based data by other bodies, or identifying the need for appropriate enhancements to them, paying attention to their desirable interoperability with Internet protocols?
- Which specification should be recommended for the mechanisms to be provided for each considered service, in order to allow its future extension to further functionalities?
- In particular, for those services and applications that utilize Internet Protocols, the following specific Questions should be studied:
- Which user requirements apply to the provision of digital services that support applications utilizing Internet Protocols (IP) and operate over bidirectional cable television systems?
- Which digital interfaces are needed to support applications utilizing Internet Protocols over cable television systems?
- Which systems implications for cable television systems derive from the requirement that they should be able to support digital services and applications that utilize Internet Protocols?
3 Tasks
Tasks include, but are not limited to the preparation of new Recommendations, that will eventually fully specify the open protocols recommended for use in the secondary distribution of the desired IP-based and/or packet-based data services and applications via the digital cable television infrastructure.
The studies should be completed by the end of the year 2006.
An up-to-date status of work under this Question is contained in the SG 9 Work Programme.
4 Relationships
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Cooperation in the study of this Question should be established with at least Study Groups 13, 15 and 16; the studies should preferably be performed in a Joint Rapporteur Group that would report to Study Group 9 and would enjoy the active participation of experts from the other study groups.
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