1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU E.726 (O 3/2 O 00) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Quality of service, network management and traffic engineering - Traffic engineering - ISDN traff
2、ic engineering Network grade of service parameters and target values for B-ISDN ITU-T Recommendation E.726 (Formerly CCITT Recommendation) ITU-T E-SERIES RECOMMENDATIONS OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS OPERATION, NUMBERING, ROUTING AND MOBILE SERVICE
3、S I NT ER NAT I ON AL OP E RAT I ON Definitions General provisions concerning Administrations General provisions concerning users Operation of international telephone services Numbering plan of the international telephone service International routing plan Tones in national signalling systems Number
4、ing plan of the international telephone service Maritime mobile service and public land mobile service OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE Charging in the international telephone service Measuring and recording call durations for accounti
5、ng purposes TELEPHONY APPLICATIONS General Phototelegraphy ISDN PROVISIONS CONCERNING USERS International routing plan NETWORK MANAGEMENT International service statistics International network management Checking the quality of the international telephone service TRAFFIC ENGINEERING Measurement and
6、recording of traffic Forecasting of traffic Determination of the number of circuits in manual operation Determination of the number of circuits in automatic and semi-automatic operation Grade of service Definitions UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON- QUALITY OF SERVICE, NETWO
7、RK MANAGEMENT AND TRAFFIC ENGINEERING ISDN traffic engineering Mobile network traffic engineering QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING Terms and definitions related to the quality of telecommunication services Models for telecommunication ser
8、vices Objectives for quality of service and related concepts of telecommunication services Use of quality of service objectives for planning of telecommunication networks Field data collection and evaluation on the performance of equipment, networks and services E. 1 OO-E. 103 E.104-E.119 E. 120-E.
9、139 E. 140-E. 159 E. 160-E. 169 E. 1 70-E. 1 79 E.180-E.189 E. 1 90-E. 1 99 E.200-E.229 E.230-E.249 E.260-E.269 E.300-E.319 E.320-E.329 E.350-E.399 E.400-E.409 E.410-E.419 E.420-E.489 E.490-E.505 E.506-E.509 E.510-E.519 E.520-E.539 E.540-E.599 E.600-E.649 E.750-E.799 E.800-E.809 E.810-E.844 E. 845-E
10、. 859 E.860-E.879 E.880-E.899 Forfurther details, please rtfer to ITU-T List of Recommendations. ITU-T RECOMMENDATION E.726 NETWORK GRADE OF SERVICE PARAMETERS AND TARGET VALUES FOR B-ISDN Summary This Recommendation provides reference connections, network Grade of Service (GOS) parameters, and targ
11、et values at both the call and the cell level for the user-plane for ATM-based B-ISDNs. The first release of E.726 applies to calls that consist of a pair of point-to-point ATM connections providing bidirectional communication between two ATM end-points. This release also assumes that switched ATM c
12、onnections are established via associated signalling as defined by Recommendations Q.2931 and Q.2761, see also E.728. This Recommendation pertains to both terrestrial and satellite- based systems. Source ITU-T Recommendation E.726 was prepared by ITU-T Study Group 2 (1997-2000) and was approved unde
13、r the WTSC Resolution No. 1 procedure on 13 March 2000. Recommendation E.726 (03/2000) 1 FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of
14、the ITU. The 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 Standardization Conference (WTSC), which meets every four years, establishes
15、the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts p
16、urview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU dra
17、ws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU membe
18、rs or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may
19、 not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 2000 All rights reserved. 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 pe
20、rmission in writing from the ITU. 11 Recommendation E.726 (03/2000) CONTENTS 1 2 3 4 5 5.1 5.2 5.3 6 7 8 8.1 9 9.1 9.2 9.3 10 10.1 10.2 11 12 Scope . References . Definitions Abbreviations General considerations Call-level GOS Cell-level GOS Effect of CAC . Reference architecture . Reference connect
21、ions for GOS parameters at the call and cell level GOS parameters at the call level . Definition of grade of service parameters . 8.1.1 Post-selection delay . 8.1.2 Answer-signal delay 8.1.3 Connection-release delay . 8.1.4 Probability of end-to-end blocking GOS parameters at the cell level . Cell-b
22、ased GOS parameters Frame-based GOS parameters 9.2.1 Frame transmission delay Throughput GOS parameters Considerations for target values Specification of target values 9.2.2 Frame discard ratio Target values for GOS parameters at the call level Target values for GOS parameters at the cell level Hist
23、ory . Annex A . Explanation of basis for target values for post-selection delay. answer-signal delay. and connection-release delay Recommendation E.726 (03/2000) Page 1 1 2 3 4 4 5 5 5 6 8 8 8 8 8 9 9 9 9 10 10 10 10 10 11 13 13 13 . 111 Recommendation E.726 NETWORK GRADE OF SERVICE PARAMETERS AND T
24、ARGET VALUES FOR B-ISDN (Geneva, 2000) 1 Scope This Recommendation provides reference connections, network Grade of Service (GOS) parameters, and target values at both the call and the cell level for the user-plane for ATM-based B-ISDNs. The first release of E.726 applies to calls that consist of a
25、pair of point-to-point ATM connections providing bidirectional communication between two ATM end-points. This release also assumes that switched ATM connections are established via associated signalling as defined by Recommendations Q.2931 and Q.2761, see also E.728. This Recommendation pertains to
26、both terrestrial and satellite- based systems. For traffic engineering, the Recommendation assumes that the network is available: that is, it does not consider network equipment in a failure state. Furthermore, outside the scope of this Recommendation are aspects peculiar to mobile and UPT services,
27、 or to B-ISDN signalling, as well as to call-level performance parameters for calls established via the management plane. This Recommendation complements the specifications in E.721,1.356 and 1.358. 2 References The following ITU-T Recommendations and other references contain provisions which, throu
28、gh reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applyi
29、ng the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. - - - - - - - ITU-T Recommendation E.492 (1 996), Trafic reference period. ITU-T Recommendation E.493 (1996), Grade of sewice (GOS) monitor
30、ing. ITU-T Recommendation E.500 (1 998), Trafic intensity measurement principles. ITU-T Recommendation E.600 (1993), Terms and definitions of trafic engineering. CCITT Recommendation E.711 (1992), User demand modelling. CCITT Recommendation E.720 (1988), ISDN grade of service concept. ITU-T Recommen
31、dation E.721 (1999), Network grade of sewice parameters and target values for circuit-switched sewices in the evolving ISDN. ITU-T Recommendation E.724 (1996), GOS parameters and target GOS objectives for IN sewices. ITU-T Recommendation E.728 (1998), Grade-of-sewice parameters for B-ISDN signalling
32、. ITU-T Recommendation E.735 (1997), Framework for trafic control and dimensioning in ITU-T Recommendation E.736 (2000), Methods for cell level trafic control in B-ISDN. ITU-T Recommendation E.737 (1 997), Dimensioning methods for B-ISDN. - - - B-ISDN. - - Recommendation E.726 (03/2000) 1 ITU-T Reco
33、mmendation E.745 (2000), Cell level measurement requirements for the ITU-T Recommendation E.800 (1994), Terms and definitions related to quality of service and network performance including dependability. ITU-T Recommendation 1.31 1 (1996), B-ISDN general network aspects. ITU-T Recommendation 1.325
34、(1 993), Reference configurations for ISDN connection types. ITU-T Recommendation 1.350 (1993), General aspects of quality of service and network performance in digital networks, including ISDN. ITU-T Recommendation 1.356 (2000), B-ISDN ATM layer cell transfer performance. ITU-T Recommendation 1.358
35、 (1998), Call processing performance for switched Virtual Channel Connections (VCCs) in a B-ISDN. ITU-T Recommendation 1.361 (1999), B-ISDN ATM layer specifcation. ITU-T Recommendation 1.37 1 (2000), Trafic control and congestion control in B-ISDN. ITU-T Recommendation Q.543 (1 993), Digital exchang
36、e performance design objectives. ITU-T Recommendation Q.706 (1993), Specifcations of Signalling System No. 7 -Message transfer part signalling performance. ITU-T Recommendation Q.709 (1993), Specifications of Signalling System No. 7 - Hypothetical signalling reference connection. ITU-T Recommendatio
37、n Q.766 (1993), Specifications of Signalling System No. 7 - Performance objectives in the integrated services digital network application. B-ISDN. ITU-T Recommendation Q.921 (1997), ISDN user-network interface - Data link layer specifcation. ITU-T Recommendation Q.2650 (1999), Interworking between S
38、ignalling System No. 7 Broadband ISDN User Part (B-ISUP) and Digital Subscriber Signalling System No. 2 (DSS2). ITU-T Recommendation Q.2761 (1999), Functional description of the B-ISDN User Part (B-ISUP) of Signalling System No. 7. ITU-T Recommendation Q.2931 (1995), Digital subscriber signalling sy
39、stem No. 2 (DSS2) - User-Network Interface (UNI) layer 3 specifcation for basic call/connection control. - - 3 Definitions For ease of reference, the definitions for Grade of Service given in E.600, and for Network Performance and Quality of Service given in E.800, are repeated herein. Grade of Serv
40、ice (GOS) is a number of traffic engineering variables used to provide a measure of adequacy of a group of resources under specified conditions. These grade of service variables may be probability of loss, dial tone delay, etc. NOTE 1 -The parameter values assigned as objectives for grade of service
41、 variables are called grade of service standards. NOTE 2 - The values of grade of service parameters achieved under actual conditions are called grade of service results. 2 Recommendation E.726 (03/2000) Quality of Service (QOS) is the collective effect of service performance which determines the de
42、gree of satisfaction of a user of the sewice. NOTE 3 - The quality of service is characterized by the combined aspects of service support performance, service operability performance, serveability performance, service security performance and other factors specific to each service. NOTE 4 - The term
43、 “quality of service“ is not used to express a degree of excellence in a comparative sense nor is it used in a quantitative sense for technical evaluations. In these cases a qualifying adjective (modifier) should be used. Network Performance is the ability of a network or network portion to provide
44、the functions related to communications between users. NOTE 5 - Network performance applies to the network providers planning, development, operations and maintenance and is the detailed technical part of QOS, excluding service support performance and human factors. NOTE 6 - Network performance is t
45、he main influence on serveability performance. NOTE 7 - Network performance measures are meaningful to network providers and are quantifiable at the part of the network to which they apply. Quality of service measures are only quantifiable at a service access point. NOTE 8 - It is up to the network
46、provider to combine the network performance parameters in such a way that the economic requirements of the network provider, as well as the satisfaction of the user, are both fulfilled. Terminology related to the architectural components and network elements in an ATM transport network follows that
47、defined in Recommendation 1.311. The terms VP switch, VC switch, and VP-VC switch defined in 1.311 are collectively referred to as ATM switch herein. Similarly, the terms VP cross-connect, VC cross-connect, and VP-VC cross-connect defined in 1.31 1 are collectively referred to as ATM cross-connect h
48、erein. Also, as specified in 1.311, VC and VP connections are unidirectional. To provide bidirectional communication in a user ATM call between two end-points, two such types of connections are therefore needed, with one in each direction. 4 Abbreviations This Recommendation uses the following abbre
49、viations: ABR ABT ANM ATC ATM B-ISDN B-ISUP CAC CPM DBR DSS GOS IAM IIP Available Bit Rate ATM Block Transfer Answer Message ATM Transfer Capability Asynchronous Transfer Mode Broadband Integrated Services Digital Network Broadband ISDN User Part Connection Admission Control Call Progress Message Deterministic Bit Rate Digital Subscriber Signalling Grade of Service Initial Address Message International Interoperator Portion Recommendation E.726 (03/2000) 3 IN1 ITP MP MPI MPT PCR PDU QOS SBR SECB UBR UNI UPT vcc VPC 5 Inter-Network Interface International Transit Portion Measurement Point Mea
