1、BSI Standards Publication BS ISO/IEC 16512-1:2016 Information technology Relayed Multicast Control Protocol (RMCP) FrameworkBS ISO/IEC 16512-1:2016 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO/IEC 16512-1:2016. The UK participation in its preparation was e
2、ntrusted to Technical Committee ICT/-/1, Information systems co-ordination. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correc
3、t application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 90433 2 ICS 35.100.70 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and St
4、rategy Committee on 30 April 2016. Amendments/correction issued since publication Date T e x t a f f e c t e dBS ISO/IEC 16512-1:2016Reference number ISO/IEC 16512-1:2016(E) ISO/IEC 2016INTERNATIONAL STANDARD ISO/IEC 16512-1 Second edition 2016-04-01 Information technology Relayed Multicast Control
5、Protocol (RMCP) Framework Technologies de linformation - Protocole de multidiffusion relay (RMCP) Cadre gnral BS ISO/IEC 16512-1:2016 ISO/IEC 16512-1:2016(E) COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2016 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or ut
6、ilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyr
7、ight office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO/IEC 2016 All rights reservedBS ISO/IEC 16512-1:2016 ISO/IEC 16512-1:2016(E) ISO/IEC 2016 All rights reserved ii-1 Foreword ISO (the Inter
8、national Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees establis
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10、eld of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed fo
11、r the different types of document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. IS
12、O and IEC shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in t
13、his document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers
14、 to Trade (TBT), see the following URL: Foreword Supplementary information. This second edition cancels and replaces firs edition of ISO/IEC 16512-1:2005 which has been technically revised. ISO/IEC 16512-1 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, in collaborat
15、ion with ITU-T. The identical text is published as ITU-T X.603 (03/2012). ISO/IEC 16512 consists of the following parts, under the general title Information technology Relayed multicast protocol: Part 1: Framework Part 2: Specification for simplex group applications BS ISO/IEC 16512-1:2016BS ISO/IEC
16、 16512-1:2016Rec. ITU-T X.603 (03/2012) iii CONTENTS Page 1 Scope 1 2 Normative references 1 3 Definitions 1 3.1 Terms defined elsewhere . 1 3.2 Terms defined in this Recommendation | International Standard 1 4 Abbreviations . 2 5 Conventions 2 6 Framework of RMCP . 2 6.1 Introduction . 2 6.2 Basic
17、concept of RMCP 3 6.3 RMCP data delivery model . 5 6.4 Security consideration in RMCP . 8 7 RMCP functions . 8 7.1 Session initiation . 8 7.2 Session subscription and join 9 7.3 Session leave . 9 7.4 Session termination . 9 7.5 Session maintenance . 9 7.6 Session monitoring 9 8 Messages 10 8.1 Basic
18、 message structure 10 8.2 Control format . 10 8.3 Sub-control format 10 Bibliography 12 BS ISO/IEC 16512-1:2016iv Rec. ITU-T X.603 (03/2012) Introduction This Recommendation | International Standard specifies the relayed multicast protocol (RMCP) used for realizing relayed multicast. Relayed multica
19、st, also known as an overlay multicast or an application-layer multicast, is a data- delivery scheme for group communications applications over an IP-based network environment. RMCP employs intermediate multicast agents for relaying application data from one or more senders to many receivers. The de
20、sign of RMCP has been motivated from the following observations: In the marketplace, diverse group applications and services have been provisioned commercially all over the world. Some of the examples include Internet TV, remote education, real-time media streaming applications, live broadcasting of
21、 special events such as the Victorias Secret Fashion Show, stock-tickers, etc. At present, most of the group applications mentioned above use a replicated IP unicast method to realize group services. As a result, those applications have scalability problems due to the limitation in supporting a numb
22、er of simultaneous users. In terms of a business model, it would mean less revenue or profit. IP multicast has been known as an effective transport technology for providing group communication services. Nevertheless, the IP multicast has not been deployed widely over the Internet due to several reas
23、ons, including the following: high deployment cost along with an uncertainty of return-on-investment (ROI) IP multicast alone cannot support all kinds of group applications. Network services such as group file transfer or network games, need a reliable multicast transport mechanism. However, even cu
24、rrent reliable multicast transport mechanisms still have unresolved problems including scalability, flow control, congestion control, etc. Until an appropriate multicast transport mechanism is laid down, group communication applications requiring reliable data transfer will continue to depend on the
25、 server-based replicated unicast method. Although IP multicast is not deployed globally, various local networks have already been equipped with IP multicast capability. For example, Ethernet-based LANs and private networks, such as corporate and campus networks, substantially provide the multicast t
26、ransport capability within their local subnet or administrative domains. Recognizing these observations, there is a crucial need to develop an alternative group delivery scheme. RMCP is one such scheme to realize group delivery over the IP-based network. RMCP utilizes existing unicast, multicast, an
27、d/or multicast tunnelling schemes. In addition, RMCP is designed in separate forms to support any kind of group service type. RMCP is expected to provide a substantial solution for group services over the IP-based network. BS ISO/IEC 16512-1:2016 ISO/IEC 16512-1:2016 (E) Rec. ITU-T X.603 (03/2012) 1
28、 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information technology Relayed multicast protocol: Framework 1 Scope Relayed multicast protocol (RMCP) is a protocol which is used to realize a relayed multicast data transport scheme. Different from the conventional IP multicast, RMCP can configure a rel
29、ayed multicast path that multicast traffic flows by using intermediate end-hosts. RMCP can be applied to the current unicast based IP network where IP multicast is not fully deployed. This Recommendation | International Standard addresses the basic concepts needed to specify RMCP for relayed multica
30、st. It defines the related terminology and proposes a framework for the future development of subsequent protocols. The framework covers network topology including network entities and the relationship among them, service scenarios, basic operations, and message format. 2 Normative references None.
31、3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation | International Standard For the purpose of this Recommendation | International Standard the following definitions apply: 3.2.1 child multicast agent (CMA): A next downstream multicast agent (MA) in the relayed
32、multicast protocol (RMCP) data delivery path. 3.2.2 IP multicast: Realizes a multicast scheme in the IP network with the help of multicast-enabled IP routers. 3.2.3 multicast: A data delivery scheme where the same data unit is transmitted from a single source to multiple destinations in a single inv
33、ocation of service. 3.2.4 multicast agent (MA): An intermediate node which relays group application data. 3.2.5 N-plex: Wherein anyone can send something, and, if someone does so, all others may receive it. 3.2.6 parent multicast agent (PMA): A next upstream multicast agent (MA) in the relayed multi
34、cast protocol (RMCP) data delivery path. 3.2.7 relayed multicast: A multicast data delivery scheme that can be used in unicast environments. 3.2.8 receiver multicast agent (RMA): A multicast agent (MA) other than sender multicast agent (SMA). 3.2.9 relayed multicast protocol (RMCP): A protocol to re
35、alize the relayed multicast scheme using end hosts. 3.2.10 relayed multicast protocol (RMCP) session: A set of multicast agents (MAs) which configures the data delivery path using RMCP. 3.2.11 session identification (SID): Corresponds to group name and identifies relayed multicast protocol (RMCP) se
36、ssion uniquely. 3.2.12 session manager (SM): A relayed multicast protocol (RMCP) entity that is responsible for the overall RMCP operations. 3.2.13 sender multicast agent (SMA): A multicast agent (MA) attached to a sender in the same system or local network. 3.2.14 simplex: Wherein only one sender i
37、s send-only and all others are receive-only. BS ISO/IEC 16512-1:2016 ISO/IEC 16512-1:2016 (E) 2 Rec. ITU-T X.603 (03/2012) 4 Abbreviations For the purposes of this Recommendation | International Standard, the following abbreviations apply: CMA Child Multicast Agent IPC Inter-Process Communication IP
38、IP IP in IP encapsulation MA Multicast Agent PMA Parent Multicast Agent RMA Receiver Multicast Agent RMCP Relayed Multicast Protocol RMT Reliable Multicast Transport SID Session ID SM Session Manager SMA Sender Multicast Agent T/TCP TCP extensions to Transactions TCP Transmission Control Protocol TP
39、 Transport Protocol UDP User Datagram Protocol 5 Conventions None. 6 Framework of RMCP 6.1 Introduction Relayed multicast protocol (RMCP) is an application-level multicast protocol. It constructs and manages a relayed multicast network to support the group communication services over the current uni
40、cast-based IP network. After a series of RMCP control connections are established, a multicast data delivery path is constructed by using multiple multicast agents (MAs). Along the delivery path, real-time or reliable data transport channels are inter-connected between upstream and downstream MAs. O
41、nly after the data delivery path and data channel are established, group communication applications can work as in the native IP multicast network. RMCP aims to support various kinds of group-based applications and services. Table 1 categorizes the group communication services with types of communic
42、ations and characteristics of data delivery. Table 1 Considerable group communication services Characteristics Type of communications Real-time data Reliable data Simplex Internet live TV, Internet live banner Stock-ticker, file dissemination, software live update N-plex Videoconference, inter-domai
43、n multicast proxy Distributed virtual environment, network game, data mirroring and caching BS ISO/IEC 16512-1:2016 ISO/IEC 16512-1:2016 (E) Rec. ITU-T X.603 (03/2012) 3 6.2 Basic concept of RMCP Each RMCP session configures relayed multicast data delivery model with the following entities as shown
44、in Figure 1: a) One session manager (SM); b) Sender multicast agent (SMA) per sender application; c) One or more receiver multicast agents (RMAs); d) Group communication applications sending or receiving group data. Sending application Receiving application Receiving application Receiving applicatio
45、n SM Sending application SMA SMA RMA RMA RMAs RMA RMA RMAFigure 1 RMCP entities The SM is involved in session configuration and maintenance. A single SM can handle one or multiple sessions, simultaneously. Since the SM does not participate in data delivery, it has RMCP control module only. Figure 2
46、shows the protocol stack of SM. Transport protocol for message delivery RMCP control module IP (unicast)Figure 2 Protocol stack of SM A session manager (SM) can provide the following functionalities: a) Session initiation; b) Session termination; c) Session membership management; d) Session status m
47、onitoring and management. BS ISO/IEC 16512-1:2016 ISO/IEC 16512-1:2016 (E) 4 Rec. ITU-T X.603 (03/2012) The MA, which covers both SMA and RMA, constructs a relayed multicast data delivery path and forwards data along the constructed path from SMA to RMA(s). An MA consists of an RMCP control module a
48、nd a data module. The main function of the control module is to establish a relayed data delivery path, and the data module is to deliver data along the constructed delivery path. Figure 3 shows the protocol stacks of the MA. Data module IP (unicast or multicast) Transport protocol for data relay RM
49、CP control moduleIP (unicast or multicast) Transport protocol for message delivery MAFigure 3 Protocol stack of the MA The RMCP control module exchanges RMCP messages with RMCP control modules in other RMCP entities. It performs the following functions: a) Session join; b) Session leave; c) Session maintenance; d) Session status report. The message flows among RMCP control modules are shown in Figure 4. As shown in the figure, an MA can be implemented in the same system with the application or in the same local network such as Ethernet-LA
