1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T X.606.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2003) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS OSI networking and system aspects Networking Information technology Enhanced Communications Transport Protocol: Specification of QoS ma
2、nagement for simplex multicast transport ITU-T Recommendation X.606.1 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS 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 Mainten
3、ance 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
4、 X.260X.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.399 MESSAGE HANDLING SYSTEMS X.400X.499 DIRECTORY X.500X.599 OSI NETWORKI
5、NG AND 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
6、Protocol 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.899 OPEN DISTRIBUTED PROCESSING X.900X
7、.999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. X.606.1 (02/2003) i INTERNATIONAL STANDARD ISO/IEC 14476-2 ITU-T RECOMMENDATION X.606.1 Information technology Enhanced Communications Transport Protocol: Specification of QoS management for simplex multicast tra
8、nsport Summary This Recommendation | International Standard (the second part of ECTP) specifies an end-to-end multicast transport protocol to support QoS negotiation, monitoring and maintenance functions in a simplex (1-to-n) multicast connection. This protocol can be used by multicast applications
9、such as real-time multimedia streaming services for supporting their QoS requirements. If QoS management is enabled, QoS parameter negotiation can optionally be performed during the connection creation phase. The controlling sender then arbitrates parameter values from those proposed by the receiver
10、s. If negotiation is not enabled, the sender imposes predefined values. The level of QoS achieved is monitored during the data transfer phase. Each receiver measures the QoS values actually experienced, and reports the status of each parameter to its parent controller using modified ACK packets. The
11、 sender aggregates the parameter status values reported from the receivers to obtain a view of connection QoS status. The sender takes QoS maintenance actions, such as data transmission rate adjustment, based upon analysis of the connection QoS status. Source ITU-T Recommendation X.606.1 was prepare
12、d by ITU-T Study Group 17 (2001-2004) and approved on 13 February 2003. An identical text is also published as ISO/IEC 14476-2. Keywords ECTP, multicast transport protocol, QoS, simplex multicast . ii ITU-T Rec. X.606.1 (02/2003) FOREWORD The International Telecommunication Union (ITU) is the United
13、 Nations specialized agency in the 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 telecommu
14、nications 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 turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the proce
15、dure 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 ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telec
16、ommunication 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 Intellectual Property Right. ITU takes no position concerning the evidence, v
17、alidity 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 received notice of intellectual property, protected by patents, which may be r
18、equired 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. ITU 2003 All rights reserved. No part of this publication may be reproduced, by any means whatsoever,
19、without the prior written permission of ITU. ITU-T Rec. X.606.1 (02/2003) iii CONTENTS Page 1 Scope 1 2 Normative references . 1 3 Definitions 2 3.1 Terms defined in ITU-T Rec. X.605 | ISO/IEC 13252 2 3.2 Terms defined in ITU-T Rec. X.606 | ISO/IEC 14476-1 2 3.3 Terms defined in this Recommendation
20、| International Standard 2 4 Abbreviations . 2 4.1 Packet types. 2 4.2 Miscellaneous 3 5 Conventions 3 6 Overview 3 7 Components for QoS management. 6 7.1 Connection information element. 6 7.2 QoS parameters . 7 7.3 QoS extension element 7 7.4 Acknowledgement element. 9 7.5 Packets used for QoS mana
21、gement . 10 8 Procedures for QoS management . 10 8.1 QoS negotiation. 10 8.1.1 Negotiation procedures . 11 8.1.2 QoS negotiation in the tree hierarchy 12 8.1.3 MSS negotiation 12 8.1.4 Resource reservation . 12 8.2 QoS monitoring. 13 8.2.1 Generation of ACK . 13 8.2.2 Measurement of QoS parameter va
22、lues. 13 8.2.3 Mapping to a parameter status value. 14 8.2.4 Reporting toward the sender . 14 8.3 QoS maintenance 15 8.3.1 Adjustment of data transmission rate 16 8.3.2 Connection pause and resume. 16 8.3.3 Troublemaker ejection 17 8.3.4 Connection termination. 17 9 Timers and variables 17 9.1 Timer
23、s . 17 9.2 Operation variables . 17 Annex A Interworking between ECTP and RSVP for resource reservation. 19 A.1 ECTP QoS parameters 19 A.2 Overview of RSVP 19 A.2.1 RSVP SENDER_TSPEC 19 A.2.2 RSVP ADSPEC 20 A.2.3 RSVP FLOWSPEC. 20 A.2.4 RSVP API . 20 A.3 An example of the parameter mapping between R
24、SVP and ECTP. 21 A.4 A scenario of interworking between ECTP and RSVP . 21 Annex B Application Programming Interfaces. 24 B.1 Overview. 24 B.1.1 API functions 24 B.1.2 Use of ECTP API functions 24 B.2 ECTP API functions 25 B.2.1 msocket(). 25 B.2.2 mbind() 26 B.2.3 maccept(). 27 B.2.4 mconnect() 28
25、iv ITU-T Rec. X.606.1 (02/2003) Page B.2.5 msend() . 28 B.2.6 mrecv() 29 B.2.7 mclose(). 30 B.2.8 mgetsockopt() and msetsockopt() . 30 B.3 An example of the msocket.h header file 32 Bibliography. 36 ITU-T Rec. X.606.1 (02/2003) v Introduction This Recommendation | International Standard specifies th
26、e Enhanced Communications Transport Protocol (ECTP), which 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 capability with the help of IGMP and IP multicas
27、t routing protocols, as shown in Figure 1. ECTP could possibly be provisioned over UDP. Internet Multicast ApplicationsEnhanced Communications Transport ProtocolIP MulticastUDPFigure 1 ECTP model ECTP is targeted to support tightly controlled multicast connections in simplex, duplex and N-plex appli
28、cations. This part of ECTP (part 2) specifies the QoS management functions for stable management of the QoS of connection users in a simplex multicast connection. QoS management functionality consists of QoS negotiation, QoS monitoring, and QoS maintenance operations. The protocol procedures for rel
29、iability control in simplex multicast transport are defined in ECTP part 1 (ITU-T Rec. X.606 | ISO/IEC 14476-1), which forms an integral part of this Recommendation | International Standard. Further parts of the standard will define control procedures and associated QoS management functions respecti
30、vely for the duplex case (X.ectp-3 | ISO/IEC 14476-3 and X.ectp-4 | ISO/IEC 14476-4) and for the N-plex case (X.ectp-5 | ISO/IEC 14476-5 and X.ectp-6 | ISO/IEC 14476-6). In ECTP, all prospective members are enrolled into a multicast group, before a connection or session is created. Those members def
31、ine an enrolled group. Each receiver in the enrolled group is referred to as an enrolled 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 t
32、he enrolment process. An ECTP connection is created for these enrolled group members. 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 top owner (TO) in this Specification. The c
33、onnection owner is responsible for overall connection management by governing the connection creation and termination, the connection pause and resumption, and the late join and leave operations. The sender triggers the connection creation process. Some or all of the enrolled receivers will particip
34、ate in the connection, becoming designated “active receivers”. Receivers active at this stage are able to participate in negotiating the desired quality of service for the session. Any enrolled receiver that is not active at this stage may participate in the connection as a late-joiner, but will hav
35、e to accept the established QoS. An active receiver can leave the connection. After the connection is created, the sender begins to transmit multicast data. While the connection is active, the sender monitors the status of the session via feedback control packets from the active receivers. The sende
36、r may take a range of actions if network problems (such as severe congestion) are indicated by the feedback received from active receivers. These actions include adjusting the data transmission rate, suspending multicast data transmission temporarily, or in the last resort, terminating the connectio
37、n. This QoS management specification can be used in the multicast applications that want to support various QoS requirements and the corresponding billing/charging models. ISO/IEC 14476-2:2003 (E) ITU-T Rec. X.606.1 (02/2003) 1 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information technology Enhan
38、ced Communications Transport Protocol: Specification of QoS management for simplex multicast transport 1 Scope This Recommendation | International Standard is an integral part of ITU-T Recs X.606.x | ISO/IEC 14476 “ECTP: Enhanced Communications Transport Protocol“, which is a family of Protocol Spec
39、ifications designed to support multicast transport services. ITU-T Rec. X.606 | ISO/IEC 14476-1 provides a specification of various protocol operations for simplex multicast transport. Those protocol operations include connection management such as connection creation/termination and connection paus
40、e/resume, membership management such as late join, user leave and membership tracking, and error control for multicast data transport such as error detection and recovery. This part of the Recommendation | International Standard provides a specification of QoS management for accomplishing desirable
41、quality of service in simplex multicast transport connection. This Specification describes the following QoS management operations: a) QoS negotiation For QoS negotiation, this Specification assumes that a desired QoS level for multicast application service can be expressed in terms of a set of QoS
42、parameters. QoS negotiation is performed via exchange of control packets between sender and receivers. Sender proposes the target values of QoS parameters obtained from the applications requirements, and then each receiver can propose modified values based on its system and/or network capacity. Send
43、er arbitrates the modified values proposed by receivers. Target values for QoS parameters can be used as input parameters for reservation of network resources. b) QoS monitoring QoS control in ECTP is based on feedback of control packets from receivers. The feedback messages from receivers enable th
44、e sender to keep track of the number of active receivers and also to monitor the connection status for multicast data transport. QoS monitoring is designed to allow the sender to diagnose the connection status in terms of QoS parameter values, and thus to take the necessary actions for maintaining t
45、he connection status at a desired QoS level. The monitored connection status will be reported to the application at the sender side. The information conveyed could provide statistics useful for billing purposes, for example. c) QoS maintenance Based on feedback information from receivers, the sender
46、 takes one or more actions so as to maintain the connection status at a desired QoS level. These QoS maintenance actions include adjustment of the data transmission rate, connection pause and resume, troublemaker ejection and connection termination operations. These QoS monitoring and maintenance fu
47、nctions, based on monitored parameter status, provide rate-based congestion control. This Recommendation | International Standard is an integral part of ITU-T Recs X.606.x | ISO/IEC 14476, which has 6 parts. All of the protocol components, including packet formats and protocol procedures specified i
48、n ITU-T Rec. X.606 | ISO/IEC 14476-1, are also valid in this Recommendation | International Standard. 2 Normative references The following Recommendations and International Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation | Internationa
49、l 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 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 Telecommunication Standardization Bureau of the ITU maintains a list of currently valid ITU-T Recomm
