1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU X.135 (08/97) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATION Public data networks - Network aspects Speed of service (delay and throughput) performance values for public data networks when providing in
2、ternational packet-switched services ITU-T Recommendation X.135 (Previously CCITT Recommendation) IT-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATION PUBLIC DATA NETWORKS X.1-X.199 Services and facilities Interfaces X.20-X.49 Transmission, signalling and switching X.50-X.89 X.
3、1 -X. 19 Maintenance Administrative arrangements OPEN SYSTEM INTERCONNECTION Model and notation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS profonnas Protocol Identification Security Protocols Layer Managed Objects Conformance testing
4、INTERWORKING BETWEEN NETWORKS General Satellite data transmission systems MESSAGE HANDLING SYSTEMS DIRECTORY OS1 NETWORKING AND SYSTEM ASPECTS Networking Efficiency Naming, Addressing and Registration Abstract Syntax Notation One (ASN.l) OS1 MANAGEMENT Systems Management framework and architecture M
5、anagement Communication Service and Protocol Structure of Management Information Management functions SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING X. 150-X. 179 X.180-X.199 X.200-X.299 X.200-X.209 X.210-X.219 X.22
6、0-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.399 X.300-X.349 x.350-x.399 X.400-X.499 X.500-X.599 X.600-X.699 X.600-X.629 X.630-X.649 X.650-X.679 X.680-X.699 X.700-X.799 X.700-X.709 X.710-X.719 X.720-X.729 X.730-X.799 X.800-X.849 X.850-X.899 X.850-X.859 X.86
7、0-X.879 X.880-X.899 X.900-X.999 For further details, please refer to ITU-T List of Recommendations. STD-ITU-T RECMN X.135-ENGL 1997 Sl 48b259L ObY3182 738 ITU-T RECOMMENDATION X.135 SPEED OF SERVICE (DELAY AND THROUGHPUT) PERFORMANCE VALUES FOR PUBLIC DATA NETWORKS WHEN PROVIDING INTERNATIONAL PACKE
8、T-SWITCHED SERVICES Summary This Recommendation defines protocol-specific speed of service parameters and values associated with each of the three data communication functions: access, user information, transfer and disengagement. Source ITU-T Recommendation X.135 was revised by ITU-T Study Group 7
9、(1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 9th August 1997. Recommendation X.135 (08/97) 1 STD-ITU-T RECMN X.135-ENGL 1997 E 4862591 Ob43183 674 E FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecomm
10、uni- cations. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of 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
11、Telecommunication Standardization Conference (WTSC), which meets every four years, establishes 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 do
12、wn in WTSC Resolution No. 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 IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunica
13、tion administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws 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, v
14、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, the ITU had not received notice of intellectual property, protected by patents, which may
15、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. 6 ITU 1998 All rights reserved. No part of this publication may be reproduced or utilized in any f
16、ormor by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation X.135 (08197) STD-ITU-T RECMN X-135-ENGL 1997 4862593 Ob43184 500 = CONTENTS Introduction References Abbreviations . Call Set-up delay . 4.1 definition of
17、 call Set-up delay at a single section boundary 4.2 definition call set-up delay between two section boundaries 4.3 Values . Data packet transfer delay 5.1 data packet transfer delay definition . 5.2 Values . Throughput parameters 6.1 throughput definition 6.2 steady-state throughput definition 6.3
18、throughput capacity definition 6.4 Values . Call clearing delay 7.1 Clear indication delay . 7.2 clear confirmation delay . Annex A . Factors to be specified in reporting throughput performance . A.l Signalling rates . A.2 Interface windows . A.3 Packet length . A.4 Additional virtual connections AS
19、 Time-of-day A.6 Direction . A.7 Throughput class . A.8 D-bit usage A.9 Delay . A.10 Reporting throughput capacity . Annex B - Ancillary information on throughput measurement and the application of throughput capacity values . Annex C . Representative end-to-end speed of service performance . Defini
20、tion of the example end-to-end connections . C.l C.2 C.3 End-to-end speed of service performance for the type 1 and type 2 configuration examples Methods for calculating mean and 95% points of delays and throughputs of packet-switched services with two or more concatenated portions . C.4 Reference N
21、otes on key assumptions, results, and implications Recommendation X.135 (08/97) Page 1 3 4 4 4 5 6 7 7 8 9 9 10 10 11 13 13 15 15 15 15 15 16 16 16 16 16 16 16 17 17 18 18 19 24 24 . 111 STDmITU-T RECMN X-135-ENGL 1997 = 4862593 Ob43185 447 Page Supplement No . 1 to Recommendation X.135 - Some test
22、results from specific national and international portions . International B portion call Set-up delay values International B portion throughput values (9600 bids) . International B portion throughput values (64 O00 bit/s) International B portion data packet transfer delay values . 2 DATEX-P network
23、testing . National B portion delay and throughput values 1 Telstra network testing . 1.1 1.2 1.3 1.4 2.1 2.2 National A portion delay and throughput values 25 25 26 27 28 29 29 29 29 iv Recommendation X.135 (08/97) STD-ITU-T RECMN XnL35-ENGL L997 Y862571 Ob43L8b 383 Recommendation X.135 SPEED OF SER
24、VICE (DELAY AND THROUGHPUT) PERFORMANCE VALUES FOR PUBLIC DATA NETWORKS WHEN PROVIDING INTERNATIONAL PACKET-SWITCHED SERVICES (revised in 1997) 1 Introduction 1.1 This Recommendation is the second in a series of four Recommendations (X.134 to X.137) that define performance parameters and values for
25、international packet-switched data communication services. Figure 1 illustrates the scope of these four Recommendations and the relationships among them. Rec. X.134 Circuit section DTE DSE I defines particular collections of basic sections, called virtual connection portions, for which performance v
26、alues will be specified; and defines a set of Packet layer reference events (PES) which provide a basis for performance parameter definition. The basic sections consist of network sections and circuit sections. They are delimited, in each case, by physical Data Terminal Equipment (DTE) or Data Switc
27、hing Exchange (DSE) interfaces. Virtual connection portions are identified either as national portions or international portions. Each PE is defined to occur when a packet crossing a section boundary changes the state of the packet layer interface. 1.3 For comparability and completeness, packet-swit
28、ched network performance is considered in the context of the 3 x 3 performance matrix defined in Recommendation X. 140. Three protocol-independent data communication functions are identified in the matrix: access, user information transfer, and disengagement. These general functions correspond to ca
29、ll Set-up, data (and interrupt) transfer, and call clearing in packet-switched virtual call services conforming to Recommendations X.25 and X.75. Each function is considered with respect to three general performance concerns (or “performance criteria“): speed, accuracy, and dependability. These expr
30、ess, respectively, the delay or rate, degree of correctness, and degree of certainty with which the function is performed. 1.4 This Recommendation defines protocol-specific speed of service parameters and values associated with each of the three data communication functions. Recommendation X. 136 de
31、fines protocol-specific accuracy and dependa- bility parameters and values associated with each function. This Recommendation and Recommendation X. 136 parameters are called “primary parameters“ to emphasize their direct derivation from packet layer reference events. 1.5 An associated two-state mode
32、l provides a basis for describing overall service availability. A specified availability function compares the values for a subset of the primary parameters with corresponding outage thresholds to classify the service as “available“ (no service outage) or “unavailable“ (service outage) during schedu
33、led service time. Recommendation X. 137 specifies the availability function and defines the availability parameters and values that characterize the resulting binary random process. 1.6 Four speed of service parameters are defined in this Recommendation: one access parameter (call Set-up delay), two
34、 user information transfer parameters (data packet transfer delay and throughput capacity), and one disengagement parameter (clear indication delay). Each parameter can be applied to any basic section or portion of a virtual connection. This generality makes the parameters useful in performance allo
35、cation and concatenation. 1.7 This Recommendation specifies delay and throughput values for national portions and international portions of two types (see Table 1). Performance values for data terminal equipment are not specified, but the parameters defined in this Recommendation may be employed in
36、such specification to assist users in establishing quantitative relationships between network performance and quality of service (see Recommendation X. 140). 1.8 Worst-case mean and 95% probability values for call Set-up delay, data packet transfer delay, throughput capacity, and clear indication de
37、lay are specified for each virtual connection portion type identified in Table 1. The term “worst case“ means that these values should be met, during any hour of scheduled service time, in the worst-performing virtual connection portion used in providing international packet-switched services. The p
38、erformance of a virtual connection portion will normally be much better than the worst-case values specified in this Recommendation1. Design objectives that take into account more demanding user applications and network performance and connectivity enhancements are for further study. Numerical metho
39、ds for combining individual portion performance values to estimate end-to-end performance are also provided in this Recommendation. DTE to DTE values for two particular hypothetical reference connections are derived using these methods in Annex C. Supplement No. 1 presents delay and throughput value
40、s measured on particular connections at particular times and is for illustrative purposes only. 2 Recommendation X.135 (08/97) Table 1lX.135 - Virtual connection portion types for which performance values are specifieda) Portion type Typical characteristics I National A International A International
41、 B 1 Terrestrial connection vi; access network section Connection via a direct terrestrial internetwork circuit section Connection via two satellite circuits and one transit network section; or via one satellite circuit and two or more transit network sections National B Connection via an access net
42、work section with one satellite circuit; or via an access network section and one or more transit network sections 2 Refer ences The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the tim
43、e 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 applying the most recent edition of the Recommendations and other references listed below
44、. A list of the currently valid ITU-T Recommendations is regularly published. ITU-T Recommendation X.l (1996), International user classes of service in, and categories of access to, public data networks and Integrated Services Digital Networks (ISDNs). ITU-T Recommendation X.2 ( 1996), International
45、 data transmission services and optional user facilities in public data networks and ISDNs. ITU-T Recommendation X.25 (1996), Interface between Data Terminal Equipment (DTE) and Data Circuit- terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks
46、 by dedicated circuit. ITU-T Recommendation X.75 (1996), Packet-switched signalling system between public networks providing data transmission services. ITU-T Recommendation X.96 (1993), Callprogress signals in public data networks. ITU-T Recommendation X.110 (1996), International routing principles
47、 and routing plan for public data networks. ITU-T Recommendation X. 134 (1 997), Portion boundaries and packet layer reference events: basis for defining packet-switched performance parameters. ITU-T Recommendation X. 136 (1997), Accuracy and dependability performance values for public data networks
48、 when providing international packet-switched services. ITU-T Recommendation X. 137 (1 997), Availability performance valuesfor public data networks when providing international packet-switched services. ITU-T Recommendation X.138 (1997), Measurement of performance values for public data networks wh
49、en providing international packet-switched services. Recommendation X.135 (08/97) 3 111 ITU-T Recommendation X.139 (1997), Echo, drop, generator and test DTEs for measurement of performance values in public data networks when providing international packet-switched services. CCITT Recommendation X.140 (1992), General qualiw of service parameters for communication via public data networks. 121 131 ITU-T Recommendation X.213 (1993, Information technology - Open Systems Interconnection - Network service definition. 141 CCITT Recommendation X.323 (1988), General arran
