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1、h IEEE Standard Definitions of Switching System Performance in a Telecommunications Environment Communications Technology Sponsored by the Switching Committee of the IEEE Communications Society Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 12:48:1
2、7 UTC from IEEE Xplore. Restrictions apply. IEEE std 973-1990 IEEE Standard Definitions of Switching System Performance in a Telecommunications Environment Sponsor SWitchingCommittee o f the IEEE Communications society Approved February 15,1990 rEm3standardsBoard Abstract: IEEE Std 973-1 990, IEEE S
3、tandard Definitions of Switching System Performance in a Telecommunications Environment, addresses 35 performance parameters for a telecommunica- tions switching system. The parameters encompass factors that affect system operations, admin- istration, and maintenance, as well as customer service. Th
4、ey are generic and are formulated from the point of view of the user. Copyright 0 1990 by The Institute of Electrical and Electronics Engineers, Inc. 345 East 47th Street, New York, NY 10017-2394, USA No part of this publication may be reproduced in any form, in an electronic retrieval system or oth
5、erwise, without the prior written permission of the publisher. Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 12:48:17 UTC from IEEE Xplore. Restrictions apply. IEEE Standards documents are developed within the Technical Committees of the IEEE Soci
6、eties and the Standards Coordinating Committees of the IEEE Standards Board. Members of the committees serve voluntarily and without compensation. They are not necessar- ily members of the Institute. The standards developed within IEEE represent a consensus of the broad expertise on the subject with
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14、31 Piscataway, NJ 08855-1331 USA IEEE Standards documents are adopted by the Institute of Electrical and Electronics Engineers without regard to whether their adoption may involve patents on articles, materials, or processes. Such adop- 1 tion does not assume any liability to any patent owner, nor d
15、oes it as- sume any obligation whatever to parties adopting the standards ldocuments. Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 12:48:17 UTC from IEEE Xplore. Restrictions apply. Foreword (This foreword is not a part of IEEE Std 973-1990, IEEE
16、 Standard Definitions of Switching System Performance in a Telecommunications Environment). This standard is prepared in conformance with the IEEE Standards Manual of December 1982 and defines performance in accordance with parameters used in the North American telephone network. This standard addre
17、sses 35 performance parameters for a telecommunications switching sys- tem. They encompass factors that affect system operations, administration, and maintenance, as well as customer service. They are generic (independent of design or implementation of the switching system). They are formulated from
18、 the point of view of the user, looking at the reactions expected by a customer or an administrator. The telecommunications field is expanding rapidly. Parameters covering new services such as ISDN, broadband, and packet switching have not been fully established. Many parameters in this standard are
19、 broad enough to define performance in a new telecommunications service. Others are limited primarily to traditional voice Public Telephone Service or analog services. The definitions are organized according to groups that have a similar impact on the user. If they are alphabetized, then their categ
20、ory should be noted. “Performance” includes both service stan- dards and reliability. Service standards generally apply to elements of a switching system that are engineered as the load on the system changes or growth occurs. Reliability generally applies to the inherent design and manufacture of a
21、system to minimize internal failures and their impact on the customer. Although the confidence of analysis may vary considerably between software and hardware problems, the reliability parameters do not distinguish between the two, and the boundaries chosen should apply to both. Each parameter is de
22、scribed in detail, its dimensions and constraints defined. However, nu- merical values are omitted. The actual numerical values can vary from one network to another. They may be allocated among network elements in different ways, and the needs of customers dif- fer for different applications. This s
23、tandard was authorized July 27, 1982, as Project 973. It was prepared by the Switching Performance Standards Subcommittee of the IEEE Communications Switching Committee. Suggestions for improvement of this standard are welcome. Members of the subcommittee are: G. T. Clark Russell G. DeWitt James C.
24、Ewin Thomas F. Gillett A. Bruce Hoadly Karl A. Greenhagle, Chairman William Karas Alan W. King Jack Kinn E. Paul Lange Benjamin Leon Fred J. Ricci Howard Shimokura Ralph Showers R. Willoughby Brian J. Wilson The following persons were on the balloting committee that approved this document for submis
25、- sion to the IEEE Standards Board: Vladimir A. Bolotin Steve Bootman Dean A. Dion John S. Edwards J. C. Ewin Larry Gitten Jiirgen Haag H. Scott Hinton Ronald W. Horn Joe G. Kappel Sal Lederman John Lemp, Jr. John Mahoney John J. OConnor Nigel Reynolds Anna A. Robrock Randy Sanders Nobuhiko Shimasak
26、i David Vlack David P. Worral Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 12:48:17 UTC from IEEE Xplore. Restrictions apply. When the IEEE Standards Board approved this standard on February 15,1990, it had the follow- ing membership: Marco W. Mi
27、gliaro, Chairman James M. Daly, Vice Chairman Andrew G. Salem, Secretary Dennis Bodson Thomas L. Hannan Paul L. Borrill Kenneth D. Hendrix Fletcher J. Buckley John W. Horch Allen L. Clapp Joseph L. Koepfinger* Stephen R. Dillon Michael A. Lawler Donald C. Fleckenstein Donald J. Loughry Jay Forster*
28、John E. May, Jr. Lawrence V. McCall L. Bruce McClung Donald T. Michael* Stig Nilsson Roy T. Oishi Gary S. Robinson Terrance R. Whittemore Donald W. Zipse *Member Emeritus Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 12:48:17 UTC from IEEE Xplore.
29、 Restrictions apply. SECTION PAGE 1 . Introduction . 7 1.1 Scope . 7 1.2 Purpose 7 1.3 References 7 2 . Customer Access . 7 2.1 Dial-Tone Delay . 7 Blocked Dial Tone . 7 2.4 Cross-Office Delay 8 3 . Switching System Availability and Reliability . 8 2.2 2.3 Postdialing Delay . 7 2.5 Answer Supervisio
30、n Delay . 8 3.1 Downtime . 8 3.2 Reliability 9 3.3 Initialization 10 4 . 5 . 6 . 7 . 8 . . Billing 10 4.2 Timing Accuracy 10 4.1 Charge Delay 10 4.3 Billing Error 10 Transmission . 10 Idle Channel Noise . 10 5.3 Impulse Noise . 1 1 5.4 Quantizing Noise . 1 1 5.5 Crosstalk . 1 1 Signal Propagation De
31、lay or Transmission Delay 11 5.9 Buffer Storage . 1 1 Operating Company Parameters 12 Service Order Process Time . 12 6.2 Diagnostic Resolution 12 6.4 Measurement Accuracy 12 Capacity Measurements and Definitions 13 5.1 5.2 Signal-to-Distortion Ratio (C-Notched Noise) 1 1 5.6 5.7 Digital Synchroniza
32、tion Slip., 1 1 5.8 Clock Accuracy . 1 1 6.1 6.3 Roll Back 12 6.5 6.6 Energy Consumption . 14 Customer Signaling 14 DTMF and Dial-Pulse Signaling Characteristics . 15 7.1 Timing . 14 7.2 Network Service 15 8.1 8.2 Outgoing Blocking . 16 Incoming Matching Loss 15 8.3 Intra-Office Blocking 16 Authoriz
33、ed licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 12:48:17 UTC from IEEE Xplore. Restrictions apply. 8.4 Tandem Blocking 16 8.5 Service Circuits . 16 Appendix Glossary of Acronyms . 17 Index 18 Authorized licensed use limited to: Tsinghua University Library.
34、Downloaded on December 25,2010 at 12:48:17 UTC from IEEE Xplore. Restrictions apply. IEEE Standard Definitions of Switching System Performance in a Telecommunications Environment 1 . Introduction 1.1 Scope. This standard provides definitions of switching system performance in a telecommunications en
35、vironment. It in- cludes parameters in seven categories: - Customer access - Network reliability - Billing - Transmission - Operating company - Customer signaling - Network service The dimensions and critical aspects of each parameter are presented without numer- ical values. The definitions will fa
36、cilitate a description of switching requirements for different networks and applications. Each application may be characterized by its own set of parameters and values. 1.2 Purpose. This standard provides defini- tions that will promote a consistent interpre- tation of performance by users, service
37、providers, manufacturers, and designers. 1.3. References. This standard shall be used in conjunction with the following publica- tions. When the following standards are superseded by an approved revision, the revi- sion shall apply. ll IEEE Std 743-1984, IEEE Standard Methods and Equipment for Measu
38、ring the Trans- mission Characteristics of Analog Voice Frequency Circuits (ANSI). IEEE publications are available from the Institute of Electrical and Electronics Engineers, Inc., Service Center, 445 Hoes Lane, Rscataway, NJ 08854-1331. 2 . Customer Access These measures are derived primarily from
39、voice telecommunication services. Similar parameters are required to charac- terize most nonvoice services. 2.1 dial-tone delay. A measure of the time it takes for a telephone switching system to re- turn a dial tone to an originating line after the customer goes off-hook. This measure is stated in
40、terms of probability that a customer line requiring connection to a Dial Pulse (DP) or Dual-Tone Multifrequency (DTMF) receiver experiences a delay of more than 3 s. These times are cumulative. 2.2 blocked dial tone. Occurs when the cus- tomer line cannot access any digit receiver because of overloa
41、d, particularly in the front- end concentrator. In some systems, overload is the major reason for extremely long dial- tone delays. 2.3 postdialing delay. The time interval be- tween the end of dialing and a physical con- nection that ensures completion or correct call disposition, insofar as these
42、are under switch control. For example, the time from seizure of a ringing circuit until the actual start of ringing (or audible ringing) is not included in postdialing delay. This interval excludes the timing period sometimes re- quired to detect the end of dialing. The origi- nating system delay ob
43、jective excludes the outpulsing interval. The terminating system delay objective excludes the interval between seizure of a ringing circuit and the start of called-party alerting and excludes the inter- val between the start of called-party alerting 7 Authorized licensed use limited to: Tsinghua Uni
44、versity Library. Downloaded on December 25,2010 at 12:48:17 UTC from IEEE Xplore. Restrictions apply. IEEE Std 973-1990 and the initiation of the audible ring signal to the caller. 2.4 cross-office delay. The interval between starting time point and ending point as de- fined below for a tandem call
45、switched cross- office. (1) Starting point: For Common Channel Signaling (CCS) incoming trunk: Receipt of the Initial Address Message (IAM). For non-Centralized Automatic Message Accounting (CAMA) per- trunk-signaling incoming trunk: End of valid called-number digit reception. For CAMA per-trunk-sig
46、naling incoming trunk: End of reception of first Automatic Number Identification (ANI) digit exclu- sive of start of dialing or Key Pulse (KP) signal and Informa- tion digit or first Operator Num- ber Identification (ONI) digit. - (2) Ending point: (a) For CCS outgoing trunk: Trans- mittal of IAM. (
47、b) For per-trunk-signaling outgoing trunk: Transmittal of connect sig- nal to next office. Where the following definitions apply: - Receipt of a CCS signal or message. Occurs when the signal or complete message becomes available for accep- tance by the processor (that is, stored in the input buffer)
48、. - Transmittal of a CCS signal or mes- sage. Occurs when the signal or com- plete message becomes available for transmission (that is, stored in the out- put buffer). - Receipt of a per-trunk-signaling su- pervisory signal. Occurs when the state transition that begins the signal is received (that i
49、s, E-lead signal or loop open or closure). All times noted are exclusive of hit timing. - Transmittal of a per-trunk-signaling supervisory signal. Occurs when the state transition that begins the sig- LEEE STANDARD DEFINITIONS OF SWITCHING SYSTEM nal occurs at the M lead (or M-lead equivalent). 2.5 answer supervision delay. The time in- terval between the transition of the called line equipment from on-hook to off-hook and transfer of the answer signal to the originat- ing system during a multi-ofice call. NOTE: To transmit an answer signal to an originating switching system in