1、 - STD-ITU-T RECMN E.459-ENGL 1998 4862591 Ob47074 34T 9 INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU E.459 (O 3/98) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Quality of service, network management and t
2、raffic engineering - Network management - Checking the quality of the international telephone service Measurements and metrics for characterizing facsimile transmission performance using non-intrusive techniques ITU-T Recommendation E.459 (Previously CCIlT Recommendation) - STDmITU-T RECMN E-459-ENG
3、L 1998 W 48b259L Ob47075 286 W ITU-T E-SERIES RECOMMENDATIONS OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES INTERNATIONAL OPERATION OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TE
4、LEPHONE SERVICE UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON- TELEPHONY APPLICATIONS ISDN PROVISIONS CONCERNING USERS QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING NETWORK MANAGEMENT E. 3 30-E. 399 International service statistics E.400-E.409 International network mana
5、gement E.410-E.419 I TRAFFIC ENGINEERING QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, I OBJECTIVES AND DEPENDABILITY PLANNING _ Forfirrther details, please refer to ITU-T List of Recommendations. ITU-T RECOMMENDATION E.459 MEASUREMENTS AND METRICS FOR CHARACTERIZING FACSIMILE TRANSMISSIO
6、N PERFORMANCE USING NON-INTRUSIVE TECHNIQUES Summary This Recommendation provides specifications for the ways in which facsimile calls can be non-intrusively monitored. Non-intrusive fax performance monitoring is done from within a network, and can provide a broad view of fax performance over the ne
7、twork being monitored. These are some significant differences between end-to-end fax performance measurement and non-intrusive measurement. The chief advantage of non-intrusive measurements is that they provide a view of performance encompassing a range of physical locations and terminals that canno
8、t be practically achieved when testing end-to-end. Source ITU-T Recommendation E.459 was prepared by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 9th of March 1998. Recommendation E.459 (03/98) i FOREWORD ITU (International Telecommunication Union
9、) is the United Nations Specialized Agency in the field of telecommuni- 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 t
10、o standardizing telecommunications on a worldwide basis. The World 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 Recommendati
11、ons 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 fail within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and EC. NOTE In this Recommendation, the expression ”Admini
12、stration” is used for conciseness to indicate both a telecommunication 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 Pr
13、operty Right. The ITU takes no position concerning the evidence, validity 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
14、 notice of intellectual property, protected by patents, which may 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. O ITU 1998 All rights reserved.
15、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 permission in writing from the ITU. ii Recommendation E.459 (03198) CONTENTS Introduction Scope References Call Data measurements . 4.1 Proto
16、col-based Call Data measurements 4.2 4.3 Analogue Call Data measurements . 4.4 Signalling-related Call Data Measurements . Cumulative data measurements 5.1 Cumulative data measurements based on T.30 protocol messages . Metrics Image related Call Data measurements . 6.1 Primary metrics . 6.3 Optional
17、 metrics 6.2 Secondary meirics . Annex A . Image measurements . A.l Basic mode A.2 Error Correction Mode . A.3 Comparison between ECM and non-ECM measurements Annex B - Analogue measurements . Annex C - Signalling information Recommendation E.459 (03/98) Page 1 1 1 2 2 3 3 4 4 4 6 6 7 7 8 8 8 9 9 10
18、 . 111 STD-ITU-T RECMN E.459-ENGL 1998 U 4Ab2591 Ob47079 921 Recommendation E.459 MEASUREMENTS AND METRICS FOR CHARACTERIZING FACSIMILE TRANSMISSION PERFORMANCE USING NON-INTRUSIVE TECHNIQUES (Geneva, 1998) 1 Introduction This Recommendation provides specifications for the ways in which facsimile ca
19、lls can be non-intrusively monitored. Non-intrusive fax performance monitoring is done from within a network, and can provide a broad view of fax performance over the network being monitored. There are some significant differences between end-to-end fax performance measurement and non-intrusive meas
20、urement. The chief advantage of non-intrusive measurements is that they provide a view of performance encompassing a range of physical locations and terminals that cannot be practically achieved when testing end-to-end. Non-intrusive testing can provide an accurate view of the quality of fax service
21、 being observed by a large number of customers using the network under observation. However, results from non-intrusive testing are affected by human factors (such as paper jams, out of paper, user clears call before completion, transactions of various sizes), and the potential contribution of termi
22、nal incompatibilities. 2 Scope This Recommendation provides a method by which large numbers of calls may be monitored, giving rise to a very large quantity of data which must be suitable for subsequent analysis. The process by which this data is gathered and subsequently analysed is divided into two
23、 operations. Firstly, measurements are taken on each individual call monitored, and these are then used to produce metrics which are useful to service providers. Some additional information is also collected, which may be of use in the further investigation of problems which have been revealed by th
24、e monitoring process. This Recommendation consists of five sections: I) Definition of the measurements which must be taken on each individual call that is monitored, referred to as call data. Definition of the cumulative data which can then be generated from the call data. Definition of three primar
25、y metrics that can be used to easily compare the performance of fax traffic over various transmission paths. Identification of some secondary metrics which are optional and correspond to those in Recommendation E.458 for test calls. Identification of optional metrics which may be useful when investi
26、gating the reasons for poor performance. 2) 3) 4) 5) The interface between the monitoring equipment and the network is outside the scope of this Recommendation. The volume and sampling of calls monitored to achieve required statistical accuracy is described in Annex AE.457. The method defined in thi
27、s Recommendation does not apply to V.34 facsimile. The monitoring of V.34 facsimile calls is for further study. 3 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of
28、 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. A
29、list of the currently valid ITU-T Recommendations is regularly published. - ITU-T Recommendation T.4 (1996), Standardization of Group 3 facsimile terminals for document transmission, - CCITT Recommendation T.6 (1988), Facsimile coding schemes and coding control functions for Group 4 facsimile appara
30、tus. Recommendation E.459 (03/98) 1 STD-ITU-T RECMN E.459-ENGL 1998 W 48b2591 Ob47080 b43 TSI CSI - IT-T Recommendation T.30 (1996), Procedures for document facsimile transmission in the general switched telephone network. ITU-T Recommendation E.450 (1993), Facsimile quality of service on PSW - Gene
31、ral aspects. IT-T Recommendation E.451 (1993), Facsimile call cut-ofperformance. IT-T Recommendation E.452 (1993), Facsimile modem speed reduction and transaction times. ITU-T Recommendation E.453 (1994), Facsimile image quality as corrupted by transmission-induced scan line errors. ITU-T Recommenda
32、tion E.454 (1 996), Transmission performance metrics for Error Correction Mode (ECM) facsimile . ITU-T Recommendation E.457 (1996), Facsimile measurement methodologies. ITU-T Recommendation E.458 ( 1996), Figure of merit for facsimile transmission performance. - - - - - - - Information If present In
33、formation If present 4 Call Data measurements Last frame of the call in each direction Call complete Four types of Call Data measurement may be made: 1) Protocol-based measurements; Information To determine whether call is complete, and if not, to provide diagnostic information. Recording of frames
34、immediately before the last frame in each direction may be necessary and is for further study. Detected MCF then DCN. “No“ indicates an incomplete call. Yes/No 2) image measurements; 3) Analogue measurements; 4) Signalling and routing information. The principal Call Data measurements described in th
35、is Recommendation may be obtained from analysis of the T.30 binary coded protocol messages. Additional information may be gained by other methods, and these are described in Annexes A, B and C. Number of RTN frames detected (Note) Fallback before first page (Note) 4.1 Protocol-based Call Data measur
36、ements Information Indicates severe transmission errors YesINo The following measurements must be recorded for each call. Measurements are either “information“, which can be extracted from T.30 protocol messages, or simple “Yes/No“ decisions on whether a condition was met. Where the type or contents
37、 of T.30 frames must be analysed, the frame must have a correct CRC. FIT at ali transmission rates (Note) Yes/No I Table 1E.459 - Protocol-based call data measurements Indicates that call has failed I I Measurement Comments I CIG I Information I Ifpresent I I Number of RTP frames detected (Note) I I
38、nformation I Indicates transmission errors I 2 Recommendation E.459 (03/98) - STD-ITU-T RECMN E-459-ENGL 3998 = 4862.593 Ob47083 58T = Disconnect after DCS DCN from transmitter Table 1IE.459 - Protocol-based call data measurements (concluded) Yes/No Yes/No Precise condition needs to be defined I Mea
39、surement Comments I DCN from receiver NSS or NSC detected CNG only Yes/No Yes/No Indicates a non-standard call Yes/No May indicate a mis-dialled fax call Pages sent at V. i 7, i 4.4 kbits Pages sent at V.17, 12 kbits I Yes/No I May indicate a mis-dialled voice call I Information Number of pages sent
40、 Information Number of pages sent Pages sent at V.17,7.2 kbit/s Pages sent at V.29,9.6 kbits riaKnt at v.17,9.6 kbit/s I Information I Number of pages sent Information Number of pages sent Information Number of pages sent Pages sent at V.29,7.2 kbit/s Pages sent at V.27 ter. 4.8 kbits Information Nu
41、mber of pages sent Information Number of pages sent Pages sent at V.27 ter, 2.4 kbit/s T.30 Annex A (ECM) Information Number of pages sent YesMo “Yes“ indicates T.30 error correction mode. “No“ indicates T.30 basic mode NOTE - Some of the protocol based-measurements must be taken from non-standardiz
42、ed actions. For instance, the number or percentage of errored lines that will result in RT“/RTN is not standardized in Recommendations T.4, T.6 and T.30; neither is the response to TCF. This means that responses will vary from manufacturer to manufacturer and perhaps even between different machines
43、from the same manufacturer. In ECM calls, capture PPR and corresponding PPS frames 64-octet frames 4.2 Image-related Call Data measurements Information PPR and PPS frame information need not be captured beyond the 10th partial page Valid only for ECM transmissions. “No“ implies 256 octets Yes/No Ima
44、ge-related Call Data measurements are made by demodulation of the T.30 phase C image data so that the image quality can be assessed independently of the protocol measurements. The use of Image-related Cali Data measurements avoids the assumptions which must be made to relate the numbers of errored l
45、ines with the occurrence of RTP and RTN messages. Measurements based on Image-related Call Data are optional, and are described in Annex A. 4.3 Analogue Call Data measurements Modern digital signal processing techniques permit the measurement of analogue transmission impairments in the presence of a
46、 modem signal. The physical connection point of the monitor will affect the measurements made. For instance, if the monitor tap point is on the 4-wire portion of network, then Echo Return Loss (Em) and echo delay can be measured. ERL cannot be reliably measured at a 2-wire monitor point. Analogue me
47、asurements are optional and are described in Annex B. Recommendation E.459 (03198) 3 STD-ITU-T RECMN E-459-ENGL 1998 4862593 Ob47082 4Lb A B C 4.4 Signalling-related Call Data Measurements Pages which are responded to with an MCF Pages that are responded to with an RTP Pages that are responded to wi
48、th an RTN Pages with less than 3% errored frames (Note) Pages with greater than 3% but less than 10% errored frames (Note) Pages with 10% or greater errored frames (Note) Examples of information that can be extracted from signalling messages are: - Called party number; - Calling party number; - Dura
49、tion of call; - Routing of call. Name Signalling messages can also give a definite indication of the start and finish of a call without which it is difficult to determine call boundaries. What How Comments PSO Collection of signalling-based information is optional, and is described in Annex C. T TSTD 5 Cumulative data measurements CALL COMPLETION DATA Total number of fax calls Total number of standard fax calls See definition of fax call above Defined to be all fax calls except 4 d facilities 3 Calls in which NSS or NSC is not returned those which use
