1、 International Telecommunication Union ITU-T X.607TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2007) SERIES X: DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY OSI networking and system aspects Networking Information technology Enhanced communications transport protocol: Specification o
2、f duplex multicast transport ITU-T Recommendation X.607 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
3、 X.150X.179 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.2
4、60X.269 Security 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 AN
5、D SYSTEM ASPECTS 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 Proto
6、col X.710X.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.89
7、9 OPEN DISTRIBUTED PROCESSING X.900X.999 TELECOMMUNICATION SECURITY X.1000 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. X.607 (02/2007) i INTERNATIONAL STANDARD ISO/IEC 14476-3 ITU-T RECOMMENDATION X.607 Information technology Enhanced communications transport p
8、rotocol: Specification of duplex multicast transport Summary This Recommendation | International Standard describes a protocol for duplex multicast transport over Internet where IP multicast is supported. Control tree mechanism for scalability and error control mechanism for reliable multicast data
9、delivery are specified. Protocol details such as packet format, parameter values and procedures are described. This protocol can be used for applications that require one-to-many as well as many-to-one data delivery services. Source ITU-T Recommendation X.607 was approved on 13 February 2007 by ITU-
10、T Study Group 17 (2005-2008) under the ITU-T Recommendation A.8 procedure. An identical text is also published as ISO/IEC 14476-3. ii ITU-T Rec. X.607 (02/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The I
11、TU Telecommunication Standardization Sector (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 Standardi
12、zation Assembly (WTSA), which meets every 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 tec
13、hnology which fall within ITU-Ts purview, 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. Compli
14、ance with this Recommendation is voluntary. 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 oblig
15、atory language such as “must“ and the negative 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 implementatio
16、n of this Recommendation may involve the 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
17、the date of approval of this Recommendation, 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
18、consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2007 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.607 (02/2007) iii CONTENTS Page 1 Scope . 1 2 Normative references 1 3 Defi
19、nitions 1 4 Abbreviations 2 5 Conventions 3 6 Overview 3 7 Design considerations 5 7.1 Participants 5 7.2 Control tree 5 7.3 Data channels. 6 7.4 Addressing. 7 7.5 Tokens 8 8 Packets. 8 8.1 Base header 8 8.2 Extension elements 10 8.3 Packet format . 13 9 Procedures 25 9.1 Connection creation. 25 9.2
20、 Late join 25 9.3 Forward data transport . 26 9.4 Token control. 27 9.5 Backward data transport . 29 9.6 Reliability control . 29 9.7 Connection management 31 Annex A Timers and parameters. 32 A.1 Timers 32 A.2 Parameters. 32 Annex B State transition diagrams 34 Annex C Application programming inter
21、faces. 36 iv ITU-T Rec. X.607 (02/2007) Introduction This Recommendation | International Standard specifies the Enhanced Communications Transport Protocol (ECTP), which is a transport protocol designed to support Internet multicast applications running over multicast-capable networks. ECTP operates
22、over IPv4/IPv6 networks that have the IP multicast forwarding capability with the help of IGMP and IP multicast routing protocols. ECTP could possibly be provisioned over UDP. ECTP is designed to support tightly controlled multicast connections in simplex, duplex and N-plex applications. This third
23、part of ECTP (ITU-T Rec. X.607 | ISO/IEC 14476-3) specifies the protocol mechanisms for reliability control in the duplex case. ECTP also provides QoS management functions for stable management of the QoS of the connection users. The procedures for QoS management of the duplex case will be defined i
24、n the duplex QoS management specification (ITU-T Rec. X.607.1 | ISO/IEC 14476-4). In the duplex multicast connection, the participants are classified into one TC-Owner and many TS-users. TC-Owner will be designated among the TS-users before the connection begins. In the duplex multicast connection,
25、the two types of data transports are supported: multicast data transport from TC-Owner to all the other TS-users and unicast data transport from TS-users to TC-Owner. After the connection is created, TC-Owner can transmit multicast data to the group, whereas each TS-user is allowed to send unicast d
26、ata to TC-Owner just after it gets a token from the TC-Owner. In ECTP, TC-Owner is at the heart of multicast group communications. It is responsible for overall connection management by governing the connection creation and termination, connection pause and resumption and the late join and leave ope
27、rations. The duplex multicast connection specified in ECTP-3 is targeted to the multicast applications in which the TC-Owner (a single multicast sender) transmits the data information to all the other TS-users, and some of the TS-users respond to the multicast sender with the unicast feedback data.
28、Basically, the duplex multicast transport will be well suited to the one-to-many multicast applications that need the unicast feedback channels from some TS-users (e.g., remote education, Internet broadcasting, etc). For example, in a remote education application, the multicast sender (lecturer) tra
29、nsmits the data such as voice, text and image to the student group, whereas some of the students may respond to the lecturer with the unicast data like questions for confirmation. It is noted that this duplex multicast connection can also be used for the some-to-many multicast applications (e.g., a
30、panel conferencing) in which a few of TS-users want to send multicast data to the group. In this scenario, the multicast data from the TS-users may first be delivered to the TC-Owner by unicast, and then TC-Owner will transmit the received unicast data to the group by multicast. For example, in the
31、panel conferencing, some of the TS-users may act as a panel and transmit multicast data via TC-Owner (the conference convener) to the listener group. The detailed use of the duplex multicast connection depends on the applications of this duplex multicast transport protocol. ISO/IEC 14476-3:2007 (E)
32、ITU-T Rec. X.607 (02/2007) 1 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information technology Enhanced communications transport protocol: Specification of duplex multicast transport 1 Scope This Recommendation | International Standard specifies the Enhanced Communications Transport Protocol (ECTP)
33、, which is a transport protocol to support Internet multicast applications over the multicast-capable IP networks. This Recommendation | International Standard specifies the ECTP part 3 (ECTP-3) for the duplex multicast transport connection in which the participants are classified into one TC-Owner
34、and many TS-users. The duplex multicast transport connection supports two kinds of data transport: the multicast data transport from TC-owner to all the other TS-users and the unicast data transport from TS-users to TC-Owner. A TS-user is allowed to send unicast data to TC-Owner, only if it gets a t
35、oken from TC-Owner. This Specification describes the protocol for supporting the duplex multicast transport, which includes the connection management (establishment, termination, pause, resumption, user join and leave) and the reliability control mechanisms for the multicast and unicast data transpo
36、rt. In particular, the protocol operations for the multicast data transport from TC-Owner to the TS-users will be designed with the congruency of the simplex multicast transport protocol (ECTP-1), as specified in ITU-T Rec. X.606 | ISO/IEC 14476-1. 2 Normative references The following Recommendation
37、s and International Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation | International Standard. At the time of publication, the editions indicated were valid. All Recommendations and Standards are subject to revision, and parties to agre
38、ements based on this Recommendation | International Standard are encouraged to investigate the possibility of applying the most recent edition of the Recommendations and Standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. The Telecommunicatio
39、n Standardization Bureau of the ITU maintains a list of currently valid ITU-T Recommendations. ITU-T Recommendation X.601 (2000), Multi-peer communications framework. ITU-T Recomendation X.602 (2004) | ISO/IEC 16513:2005, Information technology Group management protocol. ITU-T Recommendation X.605 (
40、1998) | ISO/IEC 13252:1999, Information technology Enhanced communications transport service definition. ITU-T Recommendation X.606 (2001) | ISO/IEC 14476-1:2002, Information technology Enhanced communications transport protocol: Specification of simplex multicast transport. ITU-T Recommendation X.6
41、06.1 (2003) | ISO/IEC 14476-2:2003, Information technology Enhanced communications transport protocol: Specification of QoS management for simplex multicast transport. 3 Definitions This Recommendation | International Standard is based on the following definitions, which were specified in Enhanced C
42、ommunications Transport Service (ITU-T Rec. X.605 | ISO/IEC 13252). a) Transport connection: Simplex, duplex and N-plex; b) TC-Owner and TS-users. This Recommendation | International Standard uses the following terminologies specified in Enhanced Communications Transport Protocol: part 1 (ITU-T Rec.
43、 X.606 | ISO/IEC 14476-1). a) control tree; b) parent and children; ISO/IEC 14476-3:2007 (E) 2 ITU-T Rec. X.607 (02/2007) c) TO (Top Owner): TO is a single sender of multicast data packets, which can transmit multicast data to the other TS-users, and it manages overall operations of ECTP-3. The TO w
44、ill be designated among the TS-users before the connection begins, and the TO will do the functions of TC-Owner; d) LO (Local Owner): An LO is located on the control tree of ECTP-3. One or more LOs could be designated for scalable error recovery and status monitoring in ECTP-3. An LO is also a TS-us
45、er, which can also receive the multicast data from TO. LOs will be configured as a parent of the local groups through the control tree configuration in ECTP-3; and e) LE (Leaf Entity): An LE is a leaf node on the ECTP-3 control tree. It is a TS-user in the ECTP-3 connection, and it can receive multi
46、cast data sent by TO. This Recommendation | International Standard also applies the following definitions: a) SU (Sending TS-user): Some of the ECTP-3 TS-users can send unicast data to the TO. A sending TS-user (SU) is a TS-user who gets a token from TO. Only the SU is allowed to send unicast data t
47、o TO. In other words, before sending unicast data, each user must request a token to TO. b) Token: It represents the right for a TS-user to transmit data. The TS-user who has a token is called a Sending TS-user (SU). The tokens are managed by TO. c) Forward data channel: It represents the multicast
48、data channel from TO to the group members. TO sends multicast data to all the other group members over IP multicast address. d) Backward data channel: It represents the unicast data channel, in which the data packets flow from an SU to TO. An SU can send unicast data to TO over IP unicast address. 4
49、 Abbreviations For the purposes of this Recommendation | International Standard, the following abbreviations apply, which includes the ECTP-3 packets: ACK Acknowledgment CC Connection Creation Confirm CR Connection Creation Request CT Connection Termination Request DT Data HB Heartbeat HBACK Heartbeat Acknowledgment JC Late Join Confirm JR Late Join Request LE Leaf Entity LO Local Owner LR User Leave Request ND Null Data RD Retransmission Data SU Sending TS-user TC Tree Join Confirm TGC Token Get Confirm TGR Token Get Re
