1、 International Telecommunication Union ITU-T X.608TELECOMMUNICATION 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 N-plex multicast transport ITU-T Recommendation X.608 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.608 (02/2007) i INTERNATIONAL STANDARD ISO/IEC 14476-5 ITU-T RECOMMENDATION X.608 Information technology Enhanced communications transport p
8、rotocol: Specification of N-plex multicast transport Summary This Recommendation | International Standard describes a protocol for N-plex multicast transport over Internet where IP multicast is supported. It provides the mechanisms of session control and error control. For session control, one parti
9、cipant is designated to manage creation/termination of a connection; join/leave of a participant; and tokens which allow the specific participants to send data. For error control, it provides the mechanisms of tree-based loss recovery; control tree construction with two-layer logical tree; and logic
10、al tree adaptation with packet delivery status. This Specification describes the protocol details such as packet format, procedures and parameter values. This protocol can be used for the applications which require many-to-many reliable data delivery service. Source ITU-T Recommendation X.608 was ap
11、proved on 13 February 2007 by ITU-T Study Group 17 (2005-2008) under the ITU-T Recommendation A.8 procedure. An identical text is also published as ISO/IEC 14476-5. ii ITU-T Rec. X.608 (02/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the
12、field of telecommunications. The ITU 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
13、 World Telecommunication Standardization 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
14、. In some areas of information technology 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 r
15、ecognized operating agency. Compliance 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
16、 words “shall“ or some other obligatory 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
17、that the practice or implementation 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 Recommen
18、dation development process. As of 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 an
19、d are therefore strongly urged to consult the TSB patent database at http:/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.608 (02/2007) iii CONTENTS Page 1 Scope .
20、 1 2 References 1 2.1 Normative references. 1 2.2 Informative references . 1 3 Definitions 1 4 Abbreviations 2 5 Conventions 3 6 Overview 3 7 Considerations . 5 7.1 Participants 5 7.2 Data channel and addressing . 6 7.3 Control channel and tree. 6 7.4 Tokens 8 7.5 Logical tree adaptation . 8 8 Packe
21、ts. 10 8.1 Base header 10 8.2 Extension elements 12 8.3 Packet format . 17 9 Procedures 35 9.1 Connection management 35 9.2 Logical tree management 37 9.3 Multicast data transport 42 9.4 Token control. 45 9.5 RTT measurement. 47 10 System parameters 47 Annex A Application programming interfaces. 49
22、A.1 Overview. 49 A.2 ECTP-5 API functions . 49 Annex B State transition diagrams 54 Annex C An example of system parameters values in ECTP-5 . 56 iv ITU-T Rec. X.608 (02/2007) Introduction ECTP is designed to support tightly controlled multicast connections in simplex, duplex and N-plex applications
23、. This part of ECTP (Part 5: ITU-T Rec. X.608 | ISO/IEC 14476-5) specifies the protocol mechanisms for the N-plex multicast data transport. In the N-plex multicast connection, the participants include one TC-Owner and many TS-users. TC-Owner will be designated among the TS-users before the connectio
24、n begins. TC-Owner is at the heart of multicast group communications. It is responsible for overall connection management by governing the connection creation and termination, multicast data transport, and the late join and leave operations. In the N-plex multicast connection, the multicast data tra
25、nsmissions are allowed by TS-users as well as TC-Owner. Each TS-user is allowed to send multicast data to the group only if it gets a token from the TC-Owner. That is, the multicast data transmissions of TS-users are controlled by TC-Owner. The N-plex multicast connection specified in this Recommend
26、ation | International Standard targets the many-to-many multicast applications in which many participants (TS-users) may want to transmit the multicast data to all the other TS-users. Typical examples of such applications include teleconferencing and multi-users on-line game, etc. In the teleconfere
27、ncing application, TC-Owner may act as a conferencing server, and all the other participants (TS-users) may send multicast data, such as voice, text and image, to the other participants. ISO/IEC 14476-5:2008 (E) ITU-T Rec. X.608 (02/2007) 1 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information tec
28、hnology Enhanced communications transport protocol: Specification of N-plex multicast transport 1 Scope This Recommendation | International Standard specifies the N-plex multicast transport connection in which all participants are TS-users and one of them is TC-Owner. The N-plex multicast transport
29、connection allows TS-users to send the multicast data to all the group members. It is noted that a TS-user is allowed to send the multicast data to the group, only if it gets a token from TC-Owner. This Specification describes the protocol for supporting the N-plex multicast transport, which include
30、s the connection management (establishment, termination, user join and leave) and the reliability control mechanisms for the multicast data transport. 2 References 2.1 Normative references The following Recommendations and International Standards contain provisions which, through reference in this t
31、ext, 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 agreements based on this Recommendation | International Standard are encouraged to inve
32、stigate 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 Telecommunication Standardization Bureau of the ITU maintains a list of currently valid ITU-T Recom
33、mendations. ITU-T Recommendation X.601 (2000), Multi-peer communications framework. ITU-T Recommendation X.602 (2004) | ISO/IEC 16513:2005, Information technology Group management protocol. ITU-T Recommendation X.605 (1998) | ISO/IEC 13252:1999, Information technology Enhanced communications transpo
34、rt 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.606.1 (2003) | ISO/IEC 14476-2:2003, Information technology Enhanced communications
35、 transport protocol: Specification of QoS management for simplex multicast transport. ITU-T Recommendation X.607 (2007) | ISO/IEC 14476-3:2007, Information technology Enhanced communications transport protocol: Specification of duplex multicast transport. 2.2 Informative references ITU-T Recommendat
36、ion X.607.1 (draft) | ISO/IEC 14476-4, Information technology Enhanced communications transport protocol: Specification of QoS management for duplex multicast transport. 3 Definitions This Recommendation | International Standard is based on the following definitions, which were specified in Enhanced
37、 Communications Transport Service (ITU-T Rec. X.605 | ISO/IEC 13252). a) Transport connection: Simplex, Duplex and N-plex. ISO/IEC 14476-5:2008 (E) 2 ITU-T Rec. X.608 (02/2007) This Recommendation | International Standard redefines the following definitions specified in Enhanced Communications Trans
38、port Service (ITU-T Rec. X.605 | ISO/IEC 13252). a) TC-owner (TCN): TCN manages overall operations of an N-plex multicast connection. b) transport service user (TS-user): TS-users can send and receive multicast data in the N-plex multicast connection. c) sending TS-user (SU): A TS-user who gets a to
39、ken from TCN. Only the SU is allowed to send multicast data to the group. In other words, before sending multicast data, each TS-user must request a token to TCN. This Recommendation | International Standard redefines the following terminologies specified in Enhanced Communications Transport Protoco
40、l: part 1 (ITU-T Rec. X.606 | ISO/IEC 14476-1) to accommodate to N-plex multicast connection. a) local group: A set of nodes in vicinity which has network-layer correlation in terms of packet loss and delay. b) local owner (LO): LO is a representative node of a local group and designated statically.
41、 It is responsible for maintaining an intra-group tree of the group and control trees for all SUs in its local group. Each LO is also connected to the other LOs along inter-group trees. It also generates test traffic periodically for logical tree adaptation. c) multicast data channel: TCN or SU can
42、send multicast data to all the other group members over IP multicast address. This Recommendation | International Standard newly defines the following terminologies: a) logical tree: A tree that spans all TS-users and one or more control trees are derived from it. b) inter-group tree: A per-source l
43、ogical tree of the LOs. c) intra-group tree: A shared logical tree of each local group. d) control tree: A tree along which control packets for error control are traversed. e) token: It represents the right for a TS-user to transmit multicast data. The TS-user who has a token is called SU. The token
44、s are managed by TCN. 4 Abbreviations The following acronyms for ECTP protocols are used in this Recommendation | International Standard: ECTP-1 ECTP part 1 (ITU-T Rec. X.606 | ISO/IEC 14476-1) ECTP-2 ECTP part 2 (ITU-T Rec. X.606.1 | ISO/IEC 14476-2) ECTP-3 ECTP part 3 (ITU-T Rec. X.607 | ISO/IEC 1
45、4476-3) ECTP-4 ECTP part 4 (ITU-T Rec. X.607.1 | ISO/IEC 14476-4) ECTP-5 ECTP part 5 (ITU-T Rec. X.608 | ISO/IEC 14476-5) ECTP-6 ECTP part 6 (ITU-T Rec. X.608.1 | ISO/IEC 14476-6) The following acronyms for ECTP-5 packets are used in this Recommendation | International Standard: ACK Acknowledgment C
46、C Connection Creation Confirm CCC Control Tree Change Confirm CCR Control Tree Change Request CR Connection Creation Request CT Connection Termination Request DT Data JC Late Join Confirm JR Late Join Request LR User Leave Request NACK Negative Acknowledgement PB Probe ISO/IEC 14476-5:2008 (E) ITU-T
47、 Rec. X.608 (02/2007) 3 PBACK Probe Acknowledgment RD Retransmission Data TC Tree Join Confirm TCC Tree Change Confirm TCR Tree Change Request TDC Tree Delegation Confirm TDR Tree Delegation Request TGC Token Get Confirm TGR Token Get Request TJ Tree Join Request TLC Tree Leave Confirm TLR Tree Leav
48、e Request TNC Tree Change Notification Confirm TNR Tree Change Notification Request TRC Token Return Confirm TRR Token Return Request TSR Token Status Report TSRR Token Status Report Request 5 Conventions In this Recommendation | International Standard, packets of ECTP-5 are represented as words wit
49、h all capital characters (e.g., CR for Connection Creation Request packet), and system parameters are represented as words with all italic capital characters (e.g., TD_PACKET_INT for test data packet interval). 6 Overview The Enhanced Communications Transport Protocol (ECTP) is a transport protocol designed to support Internet multicast applications. ECTP operates over IPv4/IPv6 networks that have the IP multicast forwarding capability with the help of IGMP and IP multicast routing protocols
