1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOM MUN ICATI ON STANDARDIZATION SECTOR OF ITU X.139 (08197) SERIES X: DATA NETWORKS AND OPEN SYSTEM COM M U N I CATI ON Public data networks - Network aspects Echo, drop, generator and test DTEs for measurement of performance values in public data net
2、works when providing international packet-switched services ITU-T Recommendation X.139 (Previously CCITT Recommendation) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services STD-ITU-T RECMN XmL37-ENGL 1997 4862593 Ob37808 805 ITU-T X-SERIES
3、 RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATION PUBLIC DATA NETWORKS X.1-X. 199 Services and facilities X.1-X.19 X.20-X.49 Administrative arrangements OPEN SYSTEM INTERCONNECTION X.200-X.299 Model and notation X.200-X.209 Service definitions X.210-X.219 Connection-mode protocol specific
4、ations X.220-X.229 Connectionless-mode protocol specifications X.230-X.239 X.240-X.259 Protocol Identification X.260-X.269 Security Protocols X.270-X.279 Layer Managed Objects X.280-X.289 Conformance testing X.290-X.299 INTERWORKING BETWEEN NETWORKS X.300-X.399 X.300-X.349 Satellite data transmissio
5、n systems x.350-x.399 MESSAGE HANDLING SYSTEMS X.400-X.499 X.500-X.599 X.600-X.699 X.600-X.629 X.630-X.649 Naming, Addressing and Registration X.650-X.679 OS1 NETWORKING AND SYSTEM ASPECTS Abstract Syntax Notation One (ASN.l) X.680-X.699 OS1 MANAGEMENT X.700-X.799 x.700-x.709 Management Communicatio
6、n Service and Protocol X.710-X.719 Structure of Management Information X.720-X.729 Systems Management framework and architecture Management functions x.730-x.799 X.800-X.849 OS1 APPLICATIONS X.850-X.899 Commitment, Concurrency and Recovery X.850-X.859 Transaction processing X.860-X.879 Remote operat
7、ions X.880-X.899 OPEN DISTRIBUTED PROCESSING X.900-X.999 Forjriher details, please refir to ITU-T List of Recommendations. COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesITU-T RECOMMENDATION X.139 ECHO, DROP, GENERATOR AND TEST DTEs FO
8、R MEASUREMENT OF PERFORMANCE VALUES IN PUBLIC DATA NETWORKS WHEN PROVIDING INTERNATIONAL PACKET-SWITCHED SERVICES Summary This Recommendation provides functional specifications for test sets at international packet-switched gateways for evaluation of the performance international portions according
9、to the parameters specified in X.130-Series Recommen- dations on PSPDN performance. Source ITU-T Recommendation X.139 was revised by IT-T Study Group 7 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 9th of August 1997. Recommendation X.139 (OW93 1 - COPYRIGHT Internati
10、onal Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesSTD-ITU-T RECMN X-139-ENGL 1997 48b259L Ob398LO 4b3 W FOREWORD IT (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The ITU Telecommunicat
11、ion 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 Telecommunication Standardization Co
12、nference (WTSC), which meets every four years, establishes the topics for study by the IT-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
13、areas of information technology which fall within IT-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 telecommunication administration and a recognized o
14、perating 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 IT takes no position concerning the evidence, validity or applicability of claimed Int
15、ellectual Property Rights, whether asserted by IT members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU hadhad not received notice of intellectual property, protected by patents, which may be required to implement this Recomme
16、ndation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O IT 1997 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mec
17、hanical, including photocopying and microfilm, without permission in writing fiom the ITU. 11 Recommendation X.139 (OW93 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services. STD-ITU-T RECMN X.137-ENGL L977 = 48b2571 Ob37833 3TT M CONTENTS
18、1 Introduction and scope . 1.1 General 1.2 Parameters to be measured . 1.3 Accuracy requirements of measurement . 1.4 Measurement method using echo, drop and generator DTEs . 2 References 3 Abbreviations . 4 Measurement procedure . 4.1 Call Set-up delay . Data packet transfer delay . 4.3 Throughput
19、. characteristics of echo, drop, generator and test DTEs . Common X.25 configuration and subscription parameters of the DTEs 5.3 Drop DTE . 4.2 4.4 Clear indication delay . 5 5.1 5.2 Echo DTE . . 5.4 Generator DTE 5.5 Test DTE . 6 Network location for echo, drop, generator and test DTEs Page 1 1 1 1
20、 1 2 3 3 3 5 7 9 9 9 10 10 11 11 13 . Recommendation X.139 (08197) 111 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services STD.ITU-T RECMN X.139-ENGL 1997 m 48b2591 Ob39812 23b Recommendation X.139 ECHO, DROP, GENERATOR AND TEST DTEs FOR M
21、EASUREMENT OF PERFORMANCE VALUES IN PUBLIC DATA NETWORKS WHEN PROVIDING INTERNATIONAL PACKET-SWITCHED SERVICES (revised in 1997) 1 Introduction and scope 1.1 General This Recommendation defines echo, drop, generator and test DTEs for estimating the speed of service (delays and throughput) performanc
22、e of packet-switched public data networks. 1.2 Parameters to be measured The speed of service (delays and throughput) performance values for packet-switched public data networks defined in Recommendation X.135 are as follows: - Call Set-up delay (see clause 4X.135). - Data packet transfer delay (see
23、 clause 5X.135). - Throughput (see clause 6X.135). - Clear indication delay (see clause 7X.135). Note that Recommendation X.135 considers the Quaiity of Service for networks with 9600 bih and 64 kbi/s access speeds and that this Recommendation provides means for measuring the parameters for these sp
24、eeds; higher speeds may be used in the future. 1.3 Accuracy requirements of measurement The various performance measurement techniques provide differing accuracy capabilities. The accuracy required for the measurements will depend upon the use being made of the results. The accuracy requirements imp
25、act on the perfor- mance required of.the echo, drop, generator and test DTE functions. The measured value of the delay parameters included in Recommendation X.135 can be expected to be, in most cases, significantly greater than 100 ms. Consequently, an accuracy of approximately 10 ms or less, should
26、 be sufficient in these cases. The measured value of throughput as specified in Recommendation X.135 for 9.6 kbit/s access signalling can be expected in most cases to be in the range of 1000 to 9000 bih. Consequently, an accuracy to within 100 bids or less, should be sufficient in these cases. Accur
27、acy to within 100 bids or less will also be sufficient for the cases involving 64 kbids access signalling. Recommendation X. 138 provides detailed information on measurement architectures and, in Annex A, provides detailed information on the calculation of packet-switched network performance statist
28、ics and factors which can affect their observation. 1.4 Measurement method using echo, drop and generator DTEs This subclause describes echo, drop, generator and test DTEs that can be used in estimating speed of service perfor- mance. Echo, drop and generator DTEs shall be available at international
29、 gateways for testing national and international portions. It should be noted that there may be networks where the equipment providing the remote STE does not have X.25 ports. ln such a case the network provider shall make another anangement to provide the echo, drop and generator DTE functions. Rec
30、ommendation X.139 (08/97) 1 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesAn echo DTE is a DTE used in data packet transfer delay measurements providing the data loopback function of Recom- mendation X.138. A drop DTE performs the con
31、trolled, monitored sink function of 4.1K.138, in a throughput capacity measurement. A generator DTE performs the functions of a controlled, monitored source in a throughput capacity measurement. Echo, drop and generator DTEs should respond to incoming call Set-up requests with small (or fixed and kn
32、own) delays. This will allow the echo, drop and generator DTEs to also perform the functions of an unmonitored sink in a call set-up delay measurement. A test DTE is a device most commonly provided by the tester. It pairs with the echo, drop and generator DTEs and provides the functions of a control
33、led and monitored source andor sink. Clause 4 describes the procedures for using these echo, drop, generator and test DTEs. Clause 5 specifies them in greater detail. Clause 6 specifies where they will be located within networks. 2 Refer ences The following IT-T Recommendations and other references
34、contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recom- mendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to inve
35、stigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid IT-T Recommendations is regularly published. - IT-T Recommendation X.l (1996), International user classes of service in, and categories of access to, pu
36、blic data networks and Integrated Services Digital Networks (ISDNs). - ITU-T Recommendation X.2 (1996), International 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 Dat
37、a Circuit- terminating Equipment CE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit. - ITU-T Recommendation X.75 (1 996), Packet-switched signalling system between public networks providing data transmission services. - ITU-T Recommendation X.96
38、 (1993), Callprogress signals in public data networks. - ITU-T Recommendation X.110 (1996), International routingprinciples and routingplan for public data networks. - ITU-T Recommendation X. 134 (1997), Portion boundaries and packet-layer reference events: Basis for defining packet-switched perform
39、ance parameters. - ITU-T Recommendation X.135 (1997), Speed of service (delay and throughput) performance values for public data networks when providing international packet-switched services. - ITU-T Recommendation X. 136 (1997), Accuracy and dependability performance values for public data network
40、s when providing international packet-swiiched services. - IT-T Recommendation X.137 (1997), Availability performance values for public data networks when providing international packet-switched services. - IT-T Recommendation X.138 (1997), Measurement of performance values for public data network w
41、hen providing international packet-switched services. - CCITT Recommendation X.140 (1992), General quality of service parameters for communication via public data networks. - ITU-T Recommendation X.213 (1999, Information technology - Open Systems Interconnection - Network service definition. - CCITT
42、 Recommendation X.323 (1988), General arrangements for interworking between Packet-Switched Public Data Networks (PSPDNs). 2 Recommendation X.139 (08/97) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services3 Abbreviations This Recommendatio
43、n uses the following abbreviations: DCE Data Circuit-terminating Equipment DTE Data Terminal Equipment OS1 Open Systems Interconnection RR Receiver Ready STE Signalling Terminal Equipment 4 Measurement procedure 4.1 Caii Set-up delay The call Set-up delay is deked in 4.2Bc.135. The relevant call set
44、-up delay events are shown in Figure 2M.135. The end-to-end call Set-up delay is the call set-up delay between DTE boundaries, e.g. BI and i?, in Figure 2K.135. This end-to-end delay excludes the called user response time. This end-to-end call set-up delay can be estimated by measuring the time betw
45、een the sending of a call request packet and the receipt of a call connected packet at the calling X.25 DTE boundary and subtracting the time between the incoming call packet and the call accepted packet at the called X.25 DTE boundary. For a call between the boundaries B1 and B, in Figure 2M.135 th
46、is would correspond to the value of (t2 - ti) - (f4 - t3). Hence, this measurement can be performed at one portion boundary using a DTE at the remote end of the portion or portions to be measured (for example, an echo DTE), where that DTE has a known and fixed time between the receipt of an incoming
47、 call packet and its issue of a call accepted packet. This is shown in Figures la and Ib. 4 National portion b Local international Rec. X.25 “L Figure la139 - Call Set-up delay measurement - National portion Recommendation X.139 (08/97) 3 COPYRIGHT International Telecommunications Union/ITU Telecomm
48、unicationsLicensed by Information Handling ServicesSTD-ITU-T RECMN X.139-ENGL 1997 D 4862593 Ob39815 T45 M h International portion National portion Flw -4 ;:mginternationai I I Local international Figure lbK139 - CaU set-up delay measurement - International portion Measurements are made under the fo
49、llowing conditions: - Conditions as specified in Recommendation X.135 for the observed virtuai connection which should be used if the parameters as specified in Recommendation X.135 are to be measured. Other load conditions may be used for measurements made for other reasons. A basic call, in which none of the optional user facilities defined in Recommendation X.25 are used and no call user data is sent in the call request packet. Data link layer windows of entities outside the portion being measured are open (not flow controlled). - - The call Set-up
