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FG IPTV-C-0939

INTERNATIONAL TELECOMMUNICATION UNION / Focus Group On IPTV
TELECOMMUNICATION
STANDARDIZATION SECTOR
STUDY PERIOD 2005-2008 / FG IPTV-C-0939
English only
WG(s): 4 / 6th FG IPTV meeting:
Tokyo, Japan, 15-19 October 2007
CONTRIBUTION
Source: / ETRI
Title: / Clarification on Content ID and Content Reference ID

1.  Introduction

The IPTV network acquires content from content provider and delivers it within the context of various services. The network requires content identifier for acquisition, publish, process, deployment and management activities. Unlike other identifiers, content identifier has several aspects due to the nature of content and IPTV service.

2.  Ambiguity of the term, “Content Identifier”

Figure 1 shows various aspect of content in the IPTV networks. Even a single content exists in the IPTV network as an abstract item or an instantiated item in a specific format and a specific system. Every box can be considered as the same content or the individual content. It depends on its usage context in the IPTV network.

The word “content” itself is not a well-defined term. In a narrow sense, content means some intellectual works including audio and video works or books, games and so on. In a broad sense, it means any digital item or entity. For example, MPEG-21 which defining an open framework for multimedia application doesn’t use the term “content”. Instead, it uses the term “digital item” defined as “a fundamental unit of distribution and transaction”. And ISO ISAN (International Standard Audiovisual Number) uses the term “audiovisual works”.

And the term “identifier” has two meanings in the digital industry. One meaning is just a persistent label.(e.g. user id) The other meaning implies some action or effect. URI, http://site/something , is an identifier but it implies that you can get something by the specification of http and URI.

Content identifier, in a narrow sense, is a permanent label for intellectual works. Many standard developing organizations define their own domain-specific numbering schemes and notation syntax for their identifiers, ISAN (International Standard Audiovisual Number), ISBN (International Standard Book Numbering), ISMN (International Standard Music Number), ISRC (International Standard Recoding Code) and so on.

In a wide sense, content identifier is a label specifying metadata including attributes of entity, relationship between entities and context such as time, place, and resource. Recent results from many SDOs specify content identifier in this sense.

When we specify “Content ID” as “unique identifier of Individual Content”, it can be understood as a restricted meaning.

Figure 1. Various aspects of Content in the IPTV network

3.  Usage of Content Identifier in the IPTV network

The IPTV service is the content-centric service. Thus almost all operation in the IPTV network is related to content identifier as shown in Figure 2. All transaction, shown in Figure 2, required specifying content in any format.

Content identifier for transaction between service provider and content provider should be persistent and globally interoperable. Typically, it has permanent lifetime and is managed by some naming authority such as ISAN-IA.

But content identifier for transaction between the application functions and ITF should be flexible to support all IPTV business model. It is not necessarily required to be persistent and globally interoperable. For example, a user purchases “today’s hot 10” which is meaningful only in one service provider and today. Moreover it implicitly specifies its format and quality.

When an ITF request a service, the request should specify the content which implemented in a specific format and instantiated in the context of service, time, place and resource.

When an ITF request a connection to the delivery function, the request should specify the content in the context of physical IP network resource.

Also, the specified content can be mapped into different physical resources, which are distributed to a number of servers having the same IP address.

In all cases, every transaction should designate the content with content identifier regardless its format. And the IPTV network should manage relationship between identifiers having different granularity.

Figure 2. Use cases of Content ID in the IPTV network

Although a single identification scheme can specifies all 5 use cases. In the IPTV network control perspective, it is desirable to express the required characteristics as requirements.

4.  Proposals

1.  We propose to remove the word “Individual” from the description of “Content ID” to avoid restricting the meaning.

2.  We propose the following text as a revision of paragraphs describing “locators” as a clarification for locators, CRID and content ID in a narrow sense.

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The IPTV network uses content identifier to identify content, with different granularity and in various business models. Content identifier in the IPTV network can be classified into the following five identifiers by their characteristics and use cases. The IPTV network manages mapping between these identifiers.

l  Persistent Content ID – specifies content with persistent and globally interoperable identifier. It is used for transaction between service provider and content provider, or between service providers.

l  Content Referencing ID – specifies content which is provisioned for service, and it is issued by a service provider. It may be not persistent and may be valid only in the service provider domain. It is used for transaction between a service provider and a user/subscriber.

l  Logical Locator – specifies content in the context of service, time, place and resource. It is used for requesting a service to the IPTV network. It may include the protocol and service specific information.

l  Physical Locator – specifies content in the context of physical IP network resource. It is used for establishing and routing of a delivery connection to the IPTV network. It may include the protocol, IP address and port number.

l  Internal Locator – specifies content in the context of internal delivery platform resource of a service provider. It is used for allocation and management of internal server resources of delivery platform. Especially, when servers share a single IP address, it is used for load balancing.

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