1、INTERNATIONAL TELECOMMUN CATION UN ION ITU-T TELECOMMUNICATION STAN DARD IZATI ON SECTOR OF ITU X.606 ( 1 0/200 1 ) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMM U N ICATIONS OS1 networking and system aspects - Networking Information technology - Enhanced communications transport protocol: Specificat
2、ion of simplex multicast transport ITU-T Recommendation X.606 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU X.606 ( 1 0/200 1 ) SERIES X: DATA NETWORKS AND OPEN SYSTEM COM M U N I CATI ON S OS1 networking and system aspects - Networking Information techn
3、ology - Enhanced communications transport protocol: Specification of simplex multicast transport ITU-T Recommendation X.606 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS PUBLIC DATA NETWORKS Services and facilities Interfaces Transmission, signalling and switching Netwo
4、rk aspects Maintenance Administrative arrangements Model and notation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS proformas Protocol Identification security Protocols Layer Managed Objects Conformance testing General Satellite data tra
5、nsmission systems IP-based networks MESSAGE HANDLING SYSTEMS DIRECTORY OS1 NETWORKING AND SYSTEM ASPECTS OPEN SYSTEMS INTERCONNECTION INTERWORKING BETWEEN NETWORKS Efficiency Quality of service Naming, Addressing and Registration Abstract Syntax Notation One (ASN. 1) OS1 MANAGEMENT b X. 1-X. 19 X.20
6、-X.49 X.50-X.89 X.90-X.149 X.150-X.179 X. 180-X. 199 X.200-X.209 X.21 0-X.2 19 X.220-X.229 X.230-X.239 X.240-X.259 X.260-X.269 X.270-X.279 X.280-X.289 X.290-X.299 X.300-X.349 X.350-X.369 x.370-x.399 X.400-X.499 X.500-X.599 Systems Management hmework and architecture Management Communication Service
7、and Protocol Stnicture of Management Information Management functions and ODMA functions SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING X.630-X.639 x.640-x.649 X.650-X.679 X.680-X.699 X. 700-X. 709 X.7 1 0-X.7 19 X.
8、720-X.729 x.730-x.799 X.800-X.849 X.850-X. 859 X.860-X.879 X. 8 80-X. 899 X.900-X.999 For further details, please refr to the list of ITU-TRecommendations. INTERNATIONAL STANDARD ISO/IEC 14476-1 ITU-T RECOMMENDATION X.606 Information technology - Enhanced communications transport protocol: Specifica
9、tion of simplex multicast transport Summary The Enhanced Communications Transport Protocol (ECTP) is a transport protocol designed to support Internet multicast applications running over multicast-capable networks. ECTP operates over IPv4/IPv6 networks that have the IP multicast forwarding capabilit
10、y with the help of IGMP and IP multicast routing protocols. ECTP could possibly be provisioned over UDP. ECTP is targeted to support tightly controlled multicast connections. This Recommendation I International Standard defines the protocol which provides reliability control in the simplex multicast
11、 case, adopting a tree-based approach. Other Recommendations I International Standards in the ECTP family will define the QoS management functions for the simplex case and will define reliability control and corresponding QoS management functions for the duplex case and the N-plex case. The sender i
12、s at the heart of multicast group communications. A single sender in the simplex multicast connection is assigned the role of the connection owner. The connection owner is responsible for overall connection management by governing connection creation and termination, connection pause and resumption,
13、 and join and leave operations. For tree-based reliability control, a hierarchical tree is configured during connection creation. The sender is the root of the control tree. The control tree can define a parent-child relationship between any pair of tree nodes. This treebased structure can result in
14、 local owners occurring at lower levels in the tree hierarchy as the control structure extends. Each local owner created becomes the root of its own local control tree. The connection owner will then be the root of the overall control tree. Error control is performed for each local group defined by
15、a control tree. Each parent retransmits lost data, in response to retransmission requests fiom its children. Source IT-T Recommendation X.606 was prepared by ITU-T Study Group 7 (2001-2004) and approved on 29 October 2001. An identical text is also published as ISOAEC 14476-1. ITU-T RW. X.606 (10/20
16、01) 1 FOREWORD The International Telecommunication Union (I“) is the United Nations specialized agency in the field of telecommunications. The IT Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions
17、and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in tuni, produce Recommendations on t
18、hese 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, the necessary standards are prepared on a collaborative basis with IS0 and EC. NOTE In this Recommendation, the exp
19、ression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Inte
20、llectual 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 Recommendation, ITU had not recei
21、ved notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. o ITU 2002 Ail rights reserve
22、d. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. 11 ITU-T Rec. X.606 (10/2001) CONTENTS 1 2 3 4 5 6 7 8 9 10 Scope Normative references Definitions 3.1 Ter
23、ms defined in ITU-T Rec . X.601 . 3.2 3.3 Abbreviations Terms defined in IT-T Rec . X.605 I ISO/IEC 13252 Terms defined in this Recommendation I International Standard 4.1 Packet types . 4.2 Miscellaneous Conventions Overview Protocol components 7.1 Nodes . 7.2 Control tree 7.3 Addressing . 7.4 Pack
24、ets . Protocol procedures 8.1 8.2 Connection creation . 8.3 Data transmission 8.4 Error recovery 8.5 8.6 Latejo in . 8.7 Leave . 8.8 Tree membership maintenanCe 8.9 Connection termlliation . Packet formats 9.1 Fixed header 9.2 Extension elements 9.3 Packet structure . Timers and variables . 10.1 Tim
25、ers . Operations before the connection creation Connection pause and resume . 10.2 Operation variables Annex A -Network considerations . Annex B . Tree configuration mechanisms considered in ETF RMT WG Bibliography ITU-T Rec . X.606 (10/2001) Page 1 1 1 1 1 2 2 2 3 3 3 5 5 6 7 7 8 8 9 12 13 14 14 15
26、 15 16 16 17 18 21 24 24 24 25 26 27 . 1ll Introduction This Recommendation I Intemational 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 operate
27、s over IPv4/IPv6 networks that have the IP multicast forwarding capability with the help of IGMP and IP multicast routing protocols, as shown in Figure 1. ECTP could possibly be provisioned over UDP. I Internet Multicast Applications I I Enhanced Communications Transport Protocol I I - UDP IP Multic
28、ast I I Figure 1 - ECTP Model ECTP is designed to support tightly controlled multicast connections in simplex, duplex and N-plex applications. This Part of ECTP specifies the protocol mechanisms for reliability control in the simplex case. ECTP also provides QoS management functions for stable manag
29、ement of the QoS of the connection users. Such QoS management functionality can be achieved with QoS negotiation, monitoring and maintenance operations. The protocol procedures for QoS management of the simplex case will be defined in the simplex QoS management specification (ITU-T Rec. X.606.1 I IS
30、O/IEC 14476-2), which forms an integral part of this Recommendation I International Standard. Further specifications will define control procedures and associated QoS management functions for the duplex case (ITU-T Rec. X.607 I ISO/IEC 14476-3 and ITU-T Rec. X.607.1 I ISO/IEC 14476-4) and for the N-
31、plex case (ITU-T Rec. X.608 I ISO/IEC 14476-5 and ITU-T Rec. X.608.1 I ISO/IEC 14476-6). In ECTP, ail prospective members are enrolled into a multicast group, before a connection or session is created. Those members defne an enrolled group. Each receiver in the enrolled group is referred to as an en
32、rolled receiver. In the enrolment process, each member will be authenticated. The group information, including group key and IP multicast addresses and port numbers, will be distributed to the enrolled members during the enrolment process. An ECTP connection is created for these enrolled group membe
33、rs. ECTP is targeted for tightly controlled multicast services. The sender is at the heart of multicast group communications. A single sender in the simplex multicast connection is assigned the role of the connection owner, designated as top owner (TO) in this Specification. The connection owner is
34、responsible for overall connection management by governing connection creation and termination, connection pause and resumption, and join and leave operations. The sender triggers the connection creation process. Some or all of the enrolled receivers will participate in the connection, becoming desi
35、gnated “active receivers“. Any enrolled receiver that is not active may participate in the connection as a late-joiner. An active receiver can leave the connection. After the connection is created, the sender begins to transmit multicast data. If network problems (such as severe congestion) are indi
36、cated by the ECTP QoS management functions (defined in ECTP part 2), the sender suspends multicast data transmission temporarily, invoking the connection pause operation. After a pre-specified time, the sender resumes data transmission. If all of the multicast data have been transmitted, the sender
37、terminates the connection. ECTP provides the reliability control mechanisms for multicast data transport. ECTP mechanisms are designed to keep congruency with those being proposed in the IETF. To address reliability control with scalability, the IETF has proposed three approaches: Tree based ACK (TR
38、ACK), Forward Error Correction (FEC), and Negative ACK Oriented Reliable Multicast (NORM). Each approach has its own pros and cons, and each service provider may take a different approach toward implementing reliability control. ECTP adopts the TRACK approach, because it is more similar to the exist
39、ing TCP mechanisms and more adaptive to the ECTP framework. For tree-based reliability control, a hierarchical tree is configured during connection creation. The sender is the root of the control tree. The control tree can define a parent-child relationship between any pair of tree nodes. This tree-
40、based structure can result in local owners (parents) occurring at lower levels in the tree hierarchy as the control structure extends. Each local owner created becomes the root of its own local control tree. The connection owner will then be the root of the overall control tree. Error control is per
41、formed for each local group defined by a control tree. Each parent retransmits lost data, in response to retransmission requests fkom its children. iv ITU-T Rec. X.606 (10/2001) ISO/IEC 14476-1:2002 (E) INTEmATIONAL STANDARD ISO/IEC 14476-1 ITU-T RECOMMENDATION X.606 Information technology - Enhance
42、d communications transport protocol: Specification of simplex multicast transport 1 Scope This Recommendation I International Standard specifies the Enhanced Communications Transport Protocol (ECV), which is a transport protocol designed to support Internet multicast applications over multicast-capa
43、ble IP networks. This Recommendation I International Standard specifies the ECTP for the simplex multicast transport connection that consists of one sender and many receivers. This Recommendation I International Standard specifies the protocol procedures for the following protocol operations: a) b)
44、multicast data transmission; c) d) late join and leave; e) tree membership maintenance; and f) connection termination. connection creation with tree creation; tree-based reliability control with error detection, retransmission request and retransmission; 2 Normative references The following Recommen
45、dations and International Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation I International Standard. At the time of publication, the editions indicated were valid. Ail Recommendations and Standards are subject to revision, and parties t
46、o agreements based on this Recommendation I 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 IS0 maintain registers of currently valid International Standards. The Telecommun
47、ication Standardization Bureau of the ITU maintains a list of the currently valid ITU-T Recommendations. - - ITU-T Recommendation X.601(2000), Multi-peer communicatiomfiamework. ITU-T Recommendation X.605 (1998) I ISO/IEC 13252:1999, Information technology - Enhanced Communications Transport Service
48、 Definition. 3 Definitions 3.1 This Recommendation I Intemational Standard is based on the definitions of the multicast groups developed in Multi- Peer Communications Framework (IT-T Rec. X.601). Terms defined in ITU-T Rec. X.601 a) Enrolled group; and b) Activegroup. 3.2 This Recommendation I Inter
49、national Standard is based on the concepts developed in Enhanced Communications Transport Service (ITU-T Rec. X.605 I ISO/IEC 13252). Terms defined in ITU-T Rec. X.605 I ISO/IEC 13252 a) Transport connection; and b) Simplex. ITU-T Rec. X.606 (10/2001) 1 ISO/IEC 14476-1:2002 (E) 3.3 For the purposes of this Recommendation I Intemational Standard, the following definitions apply: 3.3.1 application: Represents an Internet multicast application in this Specification. It corresponds to a transport service user in the OS1 mode. It exchanges transport service primitives with the corresponding
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