A Framework for the Usage of Internet Media Guides (IMGs)
RFC 4435
Network Working Group Y. Nomura
Request for Comments: 4435 Fujitsu Labs.
Category: Informational R. Walsh
J-P. Luoma
Nokia
H. Asaeda
Keio University
H. Schulzrinne
Columbia University
April 2006
A Framework for the Usage of Internet Media Guides (IMGs)
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document defines a framework for the delivery of Internet Media
Guides (IMGs). An IMG is a structured collection of multimedia
session descriptions expressed using the Session Description Protocol
(SDP), SDPng, or some similar session description format. This
document describes a generalized model for IMG delivery mechanisms,
the use of existing protocols, and the need for additional work to
create an IMG delivery infrastructure.
Nomura, et al. Informational [Page 1]
RFC 4435 IMG Framework April 2006
Table of Contents
1. Introduction ....................................................3
2. Terminology .....................................................3
2.1. New Terms ..................................................4
3. IMG Common Framework Model ......................................5
3.1. IMG Data Types .............................................5
3.1.1. Complete IMG Description ............................5
3.1.2. Delta IMG Description ...............................6
3.1.3. IMG Pointer .........................................6
3.2. IMG Entities ...............................................6
3.3. Operation Set for IMG Delivery .............................7
3.3.1. IMG ANNOUNCE ........................................7
3.3.2. IMG QUERY ...........................................8
3.3.3. IMG RESOLVE .........................................8
3.3.4. IMG SUBSCRIBE .......................................8
3.3.5. IMG NOTIFY ..........................................9
3.3.6. Binding between IMG Operations and Data Types .......9
3.4. Overview of Protocol Operations ...........................10
4. Deployment Scenarios for IMG Entities ..........................10
4.1. Intermediary Cases ........................................10
4.2. One-to-Many Unidirectional Multicast ......................12
4.3. One-to-One Bidirectional Unicast ..........................12
4.4. Combined Operations with Common Metadata ..................13
5. Applicability of Existing Protocols to the Proposed
Framework Model ................................................14
5.1. Existing Standard Fitting the IMG Framework Model .........14
5.2. IMG Mechanism Needs Which Are Not Met by Existing
Standards .................................................15
5.2.1. A Multicast Transport Protocol .....................16
5.2.2. Usage of Unicast Transport Protocols ...............16
5.2.3. IMG Envelope .......................................17
5.2.4. Metadata Data Model ................................18
6. Security Considerations ........................................18
7. Normative References ...........................................19
8. Informative References .........................................19
9. Acknowledgements ...............................................20
Nomura, et al. Informational [Page 2]
RFC 4435 IMG Framework April 2006
1. Introduction
Internet Media Guides (IMGs) provide and deliver structured
collections of multimedia descriptions expressed using SDP [2], SDPng
[3], or other description formats. They are used to describe sets of
multimedia services (e.g., television program schedules, content
delivery schedules) and refer to other networked resources including
web pages. IMGs provide an envelope for metadata formats and session
descriptions defined elsewhere with the aim of facilitating
structuring, versioning, referencing, distributing, and maintaining
(caching, updating) such information.
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