1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Series QTELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 51(12/2004) SERIES Q: SWITCHING AND SIGNALLING Signalling requirements for IP-QoS ITU-T Q-series Recommendations Supplement 51 ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNA
2、LLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4, 5, 6, R1 AND R2 Q.120Q.499
3、 DIGITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.11
4、99 INTELLIGENT NETWORK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799 SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) Q.1900Q.1999 BROADBAND ISDN Q.2000Q.2999 For further details, please refer to the list of ITU-T Recommendations. Q series
5、 Supplement 51 (12/2004) i Supplement 51 to ITU-T Q-series Recommendations Signalling requirements for IP-QoS Summary This Supplement specifies IP-QoS signalling requirements for the development of new or enhanced specifications. It identifies the capabilities for IP-QoS signalling. In addition, it
6、describes the essential features and models for the development of functional entity actions in support of IP-QoS signalling. Source Supplement 51 to ITU-T Q-series Recommendations was agreed on 10 December 2004 by ITU-T Study Group 11 (2005-2008). ii Q series Supplement 51 (12/2004) FOREWORD The In
7、ternational Telecommunication Union (ITU) is the United 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 Recomme
8、ndations 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 turn, produce Recommendations on these topics. The ap
9、proval 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 ISO and IEC. NOTE In this publication, the expression “Administrati
10、on“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with
11、the publication is achieved when all of these mandatory provisions are met. The 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 publication is required of any
12、 party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property
13、Rights, whether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementors are
14、 cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2005 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Q series Supplement 51
15、 (12/2004) iii CONTENTS Page 1 Scope 1 2 Introduction 2 3 References. 3 4 Definitions 3 5 Abbreviations 4 6 Functional model 5 6.1 Path-Coupled 7 6.2 Path-decoupled . 8 7 Requirements 9 7.1 User-network signalling . 9 7.2 QoS signalling at the network Network interface . 11 7.3 QoS Release 13 7.4 Pe
16、rformance 13 7.5 Symmetry of information transfer capability . 13 7.6 Contention resolution . 13 7.7 Error reporting 13 7.8 Unrecoverable failures 13 7.9 Forward and backward compatibility. 13 7.10 Parameters and values for transport connections . 14 7.11 User-initiated QoS resource modification 14
17、7.12 Emergency service 14 7.13 Reliability/priority attributes 14 8 Interfaces description of requirements 14 8.1 Call/connection control interface . 14 8.2 Network control interface. 16 8.3 Switch control interface 17 Appendix I IP signalling flows . 19 I.1 Path-coupled bearer control 19 I.2 Path-d
18、ecoupled bearer control 34 Appendix II An instance of functional model of IP QoS signalling requirements. 48 Appendix III Multi-operator scenario. 48 Appendix IV Typical process of QoS signalling in interfaces 49 Appendix V Examples to support QoS signalling requirements based on Y.1541 network QoS
19、classes, and additional information on reliability/priority 51 V.1 User-network signalling in support of network QoS class. 51 V.2 Network-network signalling. 52 V.3 Future development of classes to support reliability and priority attributes 53 iv Q series Supplement 51 (12/2004) Page Appendix VI P
20、ath-coupled and path-decoupled interoperability scenarios and scenarios with/without the participation of SeCFE/SvCFE . 53 VI.1 Path-coupled and path-decoupled interoperability scenarios. 53 VI.2 Scenarios with/without the participation of SeCFE/SvCFE. 54 Q series Supplement 51 (12/2004) 1 Supplemen
21、t 51 to ITU-T Q-series Recommendations Signalling requirements for IP-QoS 1 Scope This Supplement provides the requirements for signalling information regarding IP-based quality-of-service (QoS) at the interface between the user and the network (UNI), across interfaces between different networks (NN
22、I), including access networks. These requirements and the signalling information elements identified will enable the development of a signalling protocol(s) capable of the request, negotiation and ultimately delivery of known IP QoS classes from UNI to UNI, spanning NNIs as required. The signalling
23、requirements also address signalling information related to traffic priority and admission control, as these are also central to truly comprehensive QoS. This Supplement specifies the signalling requirements for control plane and transport control signalling in the support of Quality of Service, wit
24、hout presuming how these requirements may be met. It is based upon the following ITU-T Recs: Y.1221 9, Y.1291 8, Y.1540 6, and Y.1541 7. Figure 1 depicts the scope of this Supplement. Note that the figure does not imply that signalling data and user data will necessarily flow on the same links from
25、network to network. Figure 1 The Scope of QoS signalling requirements It is expected that continued study of IP QoS signalling requirements will address interworking/interoperability to allow hybrid signalling solutions. 2 Q series Supplement 51 (12/2004) 2 Introduction Although QoS is by definition
26、 (in multiple ISO, ITU-T and other standards) based on the experience of the service user, the mechanisms for achieving differentiated packet treatment are themselves taken all too often as being the same as “real“ end-to-end QoS. To meet specific network performance requirements such as those speci
27、fied for the QoS classes of ITU-T Rec. Y.1541 7, a network provider needs to implement services such as those specified in ITU-T Rec. Y.1221 9. To implement the transfer capabilities defined in ITU-T Rec. Y.1221 9, a network needs to provide specific user plane functionality at UNI, NNI, and INI int
28、erfaces. A network may be provisioned to meet the performance requirements of ITU-T Rec. Y.1541 7 either statically or dynamically on a per flow basis using a protocol that meets the requirements specified in this Supplement. Static network provisioning is typically performed by a network engineerin
29、g team using a network management system. Static provisioning typically takes into account both overall network performance requirements and performance requirements for individual customers based on traffic contracts between the customer and the network provider. Dynamic network provisioning at a U
30、NI and/or NNI node allows the ability to dynamically request a traffic contract for an IP flow (as defined in ITU-T Rec. Y.1221 9) from a specific source node to one or more destination nodes. In response to the request, the network determines if resources are available to satisfy the request and pr
31、ovision the network. True QoS goes beyond just the delay and loss that can occur in the transport of IP packets. The requirements include: bandwidth/capacity needed by the application, and the priority with which such bandwidth will be maintained during congestion and with which it will be restored
32、after various failure events. As these aspects of QoS can be related to routing, they go beyond the resource management of the packet transport. To make the protocol envisioned by this Supplement comprehensive, requirements on priority and admission controls are also considered. To achieve the “Hard
33、 QoS“ guarantee, networks must incorporate the following functions: 1) Network resource management with QoS sensitive scalability. 2) Intra-domain and inter-domain routing with QoS sensitivity. 3) Session admission control with QoS sensitivity. These functions must be provided whether path-coupled o
34、r path-decoupled signalling techniques are utilized within the network. The requirements in this Supplement are intended to apply to implementations that operate using path-coupled QoS control mode, path-decoupled QoS control mode, or both modes in tandem. The subject of QoS signalling has generated
35、 much interest in the industry. In particular, it is noted that some related work is under way in the IETF NSIS (Next Step in Signalling) Working Group focused on general IP signalling protocols that could be used to achieve different purposes such as QoS and security. The requirements of signalling
36、 protocols have been addressed in RFC 3726 10, in which QoS has been considered as the first-use case. The effort within the IETF is complementary to the contents of this Supplement. The IP QoS signalling solution needs to be scalable. Q series Supplement 51 (12/2004) 3 3 References This Technical R
37、eport incorporates, by dated or undated reference, provision for referencing material from other publications. These references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publi
38、cations apply to this document only when incorporated into it by amendment or revision. For undated references, the latest edition of the publication applies. 1 IETF RFC 791 (1981), Internet Protocol. 2 IETF RFC 2460 (1998), Internet Protocol, Version 6 (IPv6) Specification. 3 IETF RFC 2474 (1998),
39、Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers. 4 IETF RFC 768 (1980), User Datagram Protocol. 5 IETF RFC 793 (1981), Transmission Control Protocol. 6 ITU-T Recommendation Y.1540 (2002), Internet protocol data communication service IP packet transfer and avai
40、lability performance parameters. 7 ITU-T Recommendation Y.1541 (2002), Network performance objectives for IP-based services. 8 ITU-T Recommendation Y.1291 (2004), An architectural framework for support of Quality of Service in packet networks. 9 ITU-T Recommendation Y.1221 (2002), Traffic control an
41、d congestion control in IP-based networks. 10 IETF RFC 3726 (2004), Requirements for Signalling Protocols. 11 IETF RFC 3260 (2002), New Terminology and Clarifications for Diffserv. 12 ITU-T Recommendation G.109 (1999), Definition of categories of speech transmission quality. 13 ITU-T Recommendation
42、G.1010 (2001), End-user multimedia QoS categories. 14 ITU-T Recommendation P.911 (1998), Subjective audiovisual quality assessment methods for multimedia applications. 15 ITU-T Recommendation Q.1224 (1997), Distributed functional plane for intelligent network Capability Set 2. 4 Definitions 4.1 BCFE
43、: The BCFE is an entity that performs the Resource and Admission Control functions related to QoS requests as well as routing functions. 4.2 IP service endpoint: A functional entity which includes one type of IP signalling endpoint and the user. 4.3 IP signalling endpoint: The termination point of a
44、n IP signalling path. 4.4 IP transport packet size: Length of the payload of an IP transport protocol contained in an IP packet. 4.5 network entity: The network element responsible for terminating the IP signalling protocol. 4.6 QoS class: Identifies the category of the information that is received
45、and transmitted in the U-plane. 4 Q series Supplement 51 (12/2004) 4.7 SeCFE: The SeCFE (Session Control Functional Entity) is an entity that provides the call/session control function. 4.8 SFE: The SFE (Switching Functional Entity) is an entity that performs stream classification, i.e., QoS guarant
46、ee. 4.9 SvCFE: The SvCFE (Service Control Functional Entity) is an entity that provides value-added service functionality. 4.10 Terminal Equipment (TE): A specific implementation of an IP signalling endpoint. 4.11 transport connection: A bidirectional user plane association between two IP service en
47、dpoints at the transport layer. 4.12 transport sink address: Contains the IP address and port number, where the sender expects to receive U-plane information. 4.13 unidirectional QoS path: A unidirectional QoS path is a path along which the user data packets flow in the same direction. 4.14 user: An
48、 entity served by the IP signalling protocol. 5 Abbreviations BCFE Bearer Control Functional Entity CC Connection Control CCI Connection Control Interface CN Core Network CPN Customer Premises Network DiffServ Differentiated Services FE Functional Entity GW Gateway IETF Internet Engineering Task For
49、ce IN Intelligent Network INI Inter-Network Interface IP Internet Protocol IPDV IP Packet Delay Variation IPLR IP Packet Loss Ratio IPTD IP Packet Transfer Delay MCU Multipoint Control Unit MPLS Multi-Protocol Label Switching NC Network Control NCI Network Control Interface NNI Network-Network Interface NSIS Next Step in Signalling QoS Quality of Service SC Switch Control Q series Supplement 51 (12/2004) 5 SCI Switching Control Interface SeCFE Session Control Functional Entity SFE Swi
