1、 International Telecommunication Union ITU-T X.603.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2007) SERIES X: DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY OSI networking and system aspects Networking Information technology Relayed multicast protocol: Specification for simplex gro
2、up applications ITU-T Recommendation X.603.1 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY PUBLIC DATA NETWORKS Services and facilities X.1X.19 Interfaces X.20X.49 Transmission, signalling and switching X.50X.89 Network aspects X.90X.149 Maintenance X.150X.179
3、 Administrative arrangements X.180X.199 OPEN SYSTEMS INTERCONNECTION Model and notation X.200X.209 Service definitions X.210X.219 Connection-mode protocol specifications X.220X.229 Connectionless-mode protocol specifications X.230X.239 PICS proformas X.240X.259 Protocol Identification X.260X.269 Sec
4、urity Protocols X.270X.279 Layer Managed Objects X.280X.289 Conformance testing X.290X.299 INTERWORKING BETWEEN NETWORKS General X.300X.349 Satellite data transmission systems X.350X.369 IP-based networks X.370X.379 MESSAGE HANDLING SYSTEMS X.400X.499DIRECTORY X.500X.599 OSI NETWORKING AND SYSTEM AS
5、PECTS Networking X.600X.629 Efficiency X.630X.639 Quality of service X.640X.649 Naming, Addressing and Registration X.650X.679 Abstract Syntax Notation One (ASN.1) X.680X.699 OSI MANAGEMENT Systems Management framework and architecture X.700X.709 Management Communication Service and Protocol X.710X.
6、719 Structure of Management Information X.720X.729 Management functions and ODMA functions X.730X.799 SECURITY X.800X.849 OSI APPLICATIONS Commitment, Concurrency and Recovery X.850X.859 Transaction processing X.860X.879 Remote operations X.880X.889 Generic applications of ASN.1 X.890X.899 OPEN DIST
7、RIBUTED PROCESSING X.900X.999 TELECOMMUNICATION SECURITY X.1000 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. X.603.1 (02/2007) i INTERNATIONAL STANDARD ISO/IEC 16512-2 ITU-T RECOMMENDATION X.603.1 Information technology Relayed multicast protocol: Specification
8、for simplex group applications Summary This Recommendation | International Standard describes an application-layer protocol which constructs multicast tree for data delivery from a sender to multiple receivers over Internet where IP multicast is not fully deployed. The specified relayed multicast pr
9、otocol consists of multicast agent and session manager. This Recommendation | International Standard specifies a series of functions and procedures of multicast agent to construct one-to-many relayed data path and to relay simplex data. It also specifies the operations of session manager to manage m
10、ulticast sessions. This protocol can be used for applications that require one-to-many data delivery services, such as multimedia streaming service, file dissemination service, etc. Source ITU-T Recommendation X.603.1 was approved on 13 February 2007 by ITU-T Study Group 17 (2005-2008) under the ITU
11、-T Recommendation A.8 procedure. An identical text is also published as ISO/IEC 16512-2. ii ITU-T Rec. X.603.1 (02/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sec
12、tor (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets ever
13、y four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview
14、, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is volunta
15、ry. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the ne
16、gative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the
17、 use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendat
18、ion, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:
19、/www.itu.int/ITU-T/ipr/. ITU 2008 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. X.603.1 (02/2007) iii CONTENTS Page 1 Scope . 1 2 Normative references 1 3 Definitions 1 4 Abbreviations 2 5 Overview
20、 2 5.1 RMCP-2 entities . 3 5.2 RMCP-2 protocol block . 4 5.3 Simplex delivery model of RMCP-2 . 5 5.4 Types of RMCP-2 messages 5 6 Protocol operation 6 6.1 SMs operation 6 6.2 MAs operation . 8 7 RMCP-2 message format . 18 7.1 Common format of RMCP-2 message. 18 7.2 Control data format . 20 7.3 Mess
21、ages. 21 8 Parameters 44 8.1 Data forwarding profile 44 8.2 Parameters used in RMCP-2 45 8.3 Encoding rules to represent values used in RMCP-2. 46 Annex A Tree configuration algorithm 49 A.1 Bootstrapping rule. 49 A.2 Neighbour discovering rule . 50 A.3 HMA selection rule . 51 A.4 CMA acceptance rul
22、e. 51 A.5 Parent decision rule . 52 A.6 Tree improvement rule. 53 A.7 PMAs kicking-out rule 53 Annex B Real-time data delivery scheme . 54 B.1 Overview. 54 B.2 IP-IP tunnel mechanism for RMCP-2 real-time data delivery. 54 Annex C Reliable data delivery scheme . 56 C.1 Overview. 56 C.2 Operation 56 C
23、.3 Data encapsulation format. 58 C.4 Data profile 58 Annex D RMCP-2 API. 59 D.1 Overview. 59 D.2 RMCP-2 API functions 60 iv ITU-T Rec. X.603.1 (02/2007) Introduction Relayed MultiCast Protocol Part 2 (RMCP-2) is an application-layer relayed multicast protocol for simplex group applications. RMCP-2 c
24、an construct an optimized and robust one-to-many relayed multicast delivery path over a unicast network with the help of RMCP entities defined by ITU-T Rec. X.603 | ISO/IEC 16512-1. An RMCP-2 session consists of one SM and one or more MAs; SM initiates and terminates RMCP-2 session and manages RMCP-
25、2 session and participated MAs; MA configures an RMCP-2 tree to deliver group data by exchanging a series of RMCP-2 control messages. Along the relayed multicast delivery path, several types of data delivery channels can be constructed according to the requirement of application services. ISO/IEC 16
26、512-2:2008 (E) ITU-T Rec. X.603.1 (02/2007) 1 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information technology Relayed multicast protocol: Specification for simplex group applications 1 Scope This Recommendation | International Standard describes the Relayed MultiCast Protocol (RMCP) Part 2, an ap
27、plication-layer protocol, which constructs multicast tree for data delivery from a sender to multiple receivers over Internet where IP multicast is not fully deployed. The specified relayed multicast protocol consists of multicast agent and session manager. This Recommendation | International Standa
28、rd specifies a series of functions and procedures of multicast agent to construct one-to-many relayed data path and to relay simplex data. It also specifies the operations of session manager to manage multicast sessions. This protocol can be used for applications that require one-to-many data delive
29、ry services, such as multimedia streaming service, file dissemination service, etc. 2 Normative references The following Recommendations and International Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation | International Standard. At the
30、 time of publication, the editions indicated were valid. All Recommendations and Standards are subject to revision, and parties to agreements based on this Recommendation | International Standard are encouraged to investigate the possibility of applying the most recent edition of the Recommendations
31、 and Standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau of the ITU maintains a list of currently valid ITU-T Recommendations. ITU-T Recommendation X.601 (2000), Multi-peer communications framework
32、. ITU-T Recommendation X.603 (2004) | ISO/IEC 16512-1:2005, Information technology Relayed multicast protocol: Framework. ITU-T Recommendation X.605 (1998) | ISO/IEC 13252:1999, Information technology Enhanced communications transport service definition. ITU-T Recommendation X.606 (2001) | ISO/IEC 1
33、4476-1:2002, Information technology Enhanced communications transport protocol: Specification of simplex multicast transport. ITU-T Recommendation X.606.1 (2003) | ISO/IEC 14476-2:2003, Information technology Enhanced communications transport protocol: Specification of QoS management for simplex mul
34、ticast transport. 3 Definitions For the purposes of this Recommendation | International Standard, the following definitions apply: 3.1 multicast: A data delivery scheme where the same data unit is transmitted from a single source to multiple destinations over a single invocation of service. 3.2 IP m
35、ulticast: A multicast scheme in an IP network supported by multiple multicast-enabled IP routers. 3.3 relayed multicast: A multicast data delivery scheme that can be used in unicast environments; the scheme is based on intermediate multicast agents that relay multicast data from a media server to me
36、dia players over a tree hierarchy. 3.4 relayed multicast protocol (RMCP): A protocol that supports and manages the relayed multicast data transport. 3.5 RMCP-2 session: An MA set that uses the RMCP to configure the data delivery path. 3.6 multicast agent (MA): An intermediate data transport entity u
37、sed to relay the multicast application data. Depending on the deployment, an MA may be installed in the same system as a receiving client. 3.7 sender multicast agent (SMA): The MA attached to the sender in the same system or local network. 3.8 receiver multicast agent (RMA): The MA attached to the r
38、eceiver in the same system or local network. 3.9 head multicast agent (HMA): A representative of the MA inside a local network where the multicast is enabled. ISO/IEC 16512-2:2008 (E) 2 ITU-T Rec. X.603.1 (02/2007) 3.10 session manager (SM): An RMCP entity that is responsible for the overall RMCP op
39、erations; it may be located in the same system as the media server or located separately from the media server. 3.11 parent multicast agent (PMA): The next upstream MA in the RMCP-2 data delivery path. 3.12 child multicast agent (CMA): The next downstream MA in the RMCP-2 data delivery path. 4 Abbre
40、viations For the purposes of this Recommendation | International Standard, the following abbreviations apply: AUTH Authentication CMA Child Multicast Agent DMA Dedicated Multicast Agent HANNOUNCE HMA announce message HB Heartbeat message HLEAVE HMA leave message HMA Head Multicast Agent HSOLICIT HMA
41、 solicit message IP-IP IP in IP LEAVANS Leave answer message LEAVREQ Leave request message MA Multicast Agent MAID Multicast Agent Identification PMA Parent Multicast Agent PPROBANS Parent probe answer message PPROBREQ Parent probe request message RELANS Relay answer message RELREQ Relay request mes
42、sage RMA Receiver Multicast Agent RMCP Relayed MultiCast Protocol SDP Session Description Protocol SID RMCP-2 Session Identification SMA Sender Multicast Agent STANS Status report answer message STCOLANS Status report collect answer message STCOLREQ Status report collect request message STREQ Status
43、 report request message SUBSANS Subscription answer message SUBSREQ Subscription request message T/TCP TCP extensions to Transactions TCP Transmission Control Protocol TERMANS Ter mination answer message TERMREQ Termination request message UDP User Datagram Protocol 5 Overview The RMCP-2 is an appli
44、cation-level protocol that uses multicast agents (MAs) and a session manager (SM) to support and manage a relayed multicast data transport over a unicast-based Internet. With the help of the SM, the RMCP-2 ISO/IEC 16512-2:2008 (E) ITU-T Rec. X.603.1 (02/2007) 3 begins by constructing a relayed multi
45、cast control tree that consists of MAs. Consequently with the preconfigured control tree, each MA connects appropriate data channels with each other. The RMCP-2 entities for a simplex delivery model are described in clause 5.1. 5.1 RMCP-2 entities The RMCP-2 entities are the same as those described
46、in RMCP Part 1. As shown in Figure 1, each RMCP-2 session constructs a relayed multicast data delivery model with the following entities: a) one SM; b) one sender multicast agent (SMA) per sender application; c) one or more receiver multicast agents (RMAs); d) one or more sending or receiving group
47、applications. An SM, which can handle one or multiple sessions simultaneously, can be implemented separately or as a part of other entities in an RMCP-2 session. X.603.1(07)_F01SessionmanagerRMA RMA RMARMAsSMAReceivingapp.Sendingapp.Receivingapp.Receivingapp.Figure 1 RMCP-2 service topology An SM ca
48、n provide the following functionalities: a) session initialization; b) session release; c) session membership management; d) session status monitoring. An MA, which refers to both the SMA and the RMA, constructs a relayed multicast delivery path from one sender to many receivers and then forwards da
49、ta along the constructed path, can provide the following functionalities: a) session initialization; b) session join; c) session leave; d) session maintenance; e) session status reporting; f) application data relay. ISO/IEC 16512-2:2008 (E) 4 ITU-T Rec. X.603.1 (02/2007) 5.2 RMCP-2 protocol block An SM should exchange control messages with other MAs to control and manage RMCP-2 session. The control messages used by SM should be delivered reliably; otherwise, RMCP-2 session becomes unrecoverab
