1、I STDmITU-T RECMN E-SOL-ENGL 1777 4Ab2571 Ob38774 705 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU E501 (05/97) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Quality of service, network management and traffi
2、c engineering - Traffic engineering - Measurement and recording of traffic Estimation of traffic offered in the network ITU-T Recommendation E501 (Previously CCITT Recommendation) STD-ITU-T RECMN E.5OL-ENGL 1777 m 48b259L Ut238775 b4L m ITU-T E-SERZES RECOMMENDATIONS OVERALL NETWORK OPERATION, TELEP
3、HONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS 3PERATION, NUMBERING, ROUTING AND MOBILE SERVICES INTERNATIONAL OPERATION OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE UTILIZATION OF THE INTEFWATIONAL TELEPHONE NETWORK FOR NON- TELEPHONY APPLICAT
4、IONS ISDN PROVISIONS CONCERNING USERS QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING NETWORK MANAGEMENT International service statistics International network management Checking the quality of the international telephone service TRAFFIC ENGINEERING E.lOO-E.229 E.230-E.299 E.300-E.32
5、9 E. 3 30-E. 3 99 E.400-E.489 E.400-E.409 E.4 1 0-E.4 19 E.420-E.489 E.49-E.799 E.49eE.505 * 1 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 ISDN traffi
6、c 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 services Objectives for quality of service and rela
7、ted concepts of telecommunication services Use of quality of service objectives for planning of telecommunication networks E.506-ES09 E.510-ES19 E.520-ES39 E.540-ES99 E.600-E.699 E.700-E.749 E.750-E.799 E.800-E.899 E.800-E309 E.810-E.844 E.845-E.859 E.86C-E.879 Field data collection and evaluation o
8、n the performance of equipment, networks and services E.880-E.899 For further details, please refer to ITU-T List of Recommendations. STD-ITU-T RECMN E.5OL-ENGL 1997 W Yb2591 Ob3877b 58B m ITU-T RECOMMENDATION E.501 ESTIMATION OF TRAFFIC OFFERED IN THE NETWORK Summary This Recommendation contains es
9、timation procedures for the traffic offered to a circuit-switched network. Methods to estimate the traffic offered to a circuit group and the origin-destination traffic, based on circuit group measurements, are described. Source ITU-T Recommendation ES01 was revised by ITU-T Study Group 2 (1997-2000
10、) and was approved under the WTSC Resolution No. 1 procedure on the 26th of May 1997. Recommendation E.501 (05/97) 1 STD-ITU-T RECMN E-SOL-ENGL L777 48b259L Ob38777 4111 D FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- catio
11、ns. 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 Telecommun
12、ication 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 lhe procedure laid down in WTSC
13、 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 telecommunication admin
14、istration 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, validity or
15、 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 IT hadhad not received notice of intellectual property, protected by patents, which may be requi
16、red 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 1997 All rights reserved. No part of this publication may be reproduced or utilized in any form or b
17、y any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the IT. 11 Recommendation E.501 (05/97) 1 2 3 4 5 6 7 8 STDBITU-T RECMN E-SOL-ENGL 1997 = Lib259L Ob38778 350 = CONTENTS Introduction Scope References Only-path circuit group 4.1 No signif
18、icant congestion . 4.2 Significant congestion High-usage group with no significant congestion on the final group . High-usage group with significant congestion on the final group Origin-destination equivalent traffic offered on the totality of call attempts are available . only on a sampling basis a
19、re available of traffic intensity are available High-usage/final circuit group arrangement . 5.1 5.2 6.1 6.2 6.3 Determination of origin-destination traffic offered when origin-destination traffic measurements Determination of origin-destination traffic offered when origin-destination traffic measur
20、ements Determination of origin-destination traffic offered when only circuit-group based measurements History Bibliography . Annex A . A simplified model for the formula presented in 4.2 Annex B - Equivalent traffic offered intensity on circuit group basis are available . Notation, derivation, and s
21、olution of Formula 6-1 in 6.3 . C.2 The pseudo-inverse . C.3 The iterative algorithm Annex D - Examples of application of the methods described in Annex C . D.l Example 1 . Annex C - Methods for determination of origin-destination traffic offered when only the measurements of traffic C.l Bibliograph
22、y . D.2 Example 2 . Annex E - A sample performance evaluation of the pseudo-inverse and of the iterative algorithm Page 1 2 2 2 2 2 3 3 3 4 4 4 4 5 5 5 10 10 10 12 12 14 14 14 16 19 . Recommendation E.501 (05/97) 111 STD.ITU-T RECMN E-SOL-ENGL 1997 m 48b257L Ob38779 297 D Recommendation ES01 ESTIMAT
23、ION OF TRAFFIC OFFERED IN THE NETWORK (revised 1997) 1 Introduction For planning the growth of the network, the following quantities must be estimated from measurements: - - - traffic offered to exchanges; - traffic offered to circuit groups; traffic offered to destinations, on an origin-destination
24、 basis; call attempts offered to exchanges; - traffic offered to signalling links. These quantities are normally estimated from measurements of busy-hour carried traffic and call attempts, but there are a number of factors which may need to be taken into account within the measurement and estimation
25、 procedures: a) Measurements may need to be subdivided, e.g. on a destination basis, or by call type (for example, calls using different signalling systems). It may not be possible to obtain a complete record of traffic carried. FOT example, in a network with high usage and final groups, it may not
26、be possible to measure the traffic overflowing from each high usage group. Measurements may be affected by congestion. This will generally result in a decrease in traffic carried, but the decrease may be affected by customers repeat attempts and by the actions (for example, automatic repeat attempts
27、) of other network components. When high levels of congestion persist for a lengthy period (many days), some customers may avoid making calls during the congested period of each day. This apparent missing component of offered traffic is known as suppressed traffic. It should be taken into account in
28、 planning since the offered traffic will increase when the equipment is augmented. At present, suitable algorithms for estimating suppressed traffic have not been defined. b) c) d) Three situations should be distinguished: i) Congestion upstream of the measurement point - This is not directly observ
29、able. ii) Congestion due to the measured equipment - Congestion measurements should be used to detect this. iii) Congestion downstream of the measurement point - This can often be detected from measurements of ineffective traffic or completion ratio. Note that where groups are both way, congestion e
30、lsewhere in the network may be both upstream and downstream of the measurement point for different parcels of traffic. When congestion is due to the measured equipment, this must be properly accounted for in the estimation of traffic offered which is used for planning the growth of the measured equi
31、pment. When congestion arises elsewhere in the network, the planner needs to consider whether or not the congestion will remain throughout the considered planning period. This may be difficult if he does not have control of the congested equipment. This Recommendation presents estimation procedures
32、for two of the situations described above. Clauses 4 and 5 have the aim of the determination of traffic offered to circuit group, and namely clause 4 deals with the estimation of traffic offered to a fully-operative only-path circuit group which may be in significant congestion. Clause 5 deals with
33、a high- usage and final group arrangement with no significant congestion. Clause 6 provides a procedure to determine traffic offered to destinations on an origin-destination basis, when only measurements of traffic intensity on circuit groups are available or when direct measurements on origin-desti
34、nation traffic offered are also available. In clause 6 the estimated traffic offered is the “equivalent traffic offered“ used in the pure lost call model as defined in Annex B, while in clauses 4 and 5 in the evaluation of traffic offered, the users repeat attempts are taken into account. Recommenda
35、tion ES01 (05197) 1 STD.ITU-T RECMN E-SUL-ENGL 1997 48b2.571 Ob38780 TU9 These estimation procedures should be applied to individual busy-hour measurements. The resulting estimates of traffic offered in each hour should then be accumulated according to the procedures described in Recommendation E.50
36、0. 2 Scope This Recommendation provides means of estimating the traffic offered to circuit groups based on measurements of traffic carried and means of estimating origin-destination traffic flows based on circuit group measurements. 3 References The following ITU-T Recommendations and other referenc
37、es contain provisions which, through 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 inv
38、estigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regul-arly published. - - CCITT Recommendation E.502 ( 1992), Trac measurement requirements for digiial telecommunication CCIT
39、T Recommendation ES00 (1992), Trafic intensiv measurement principles. exchanges. 4 Only-path circuit group 4.1 No significant congestion Traffic offered will equal traffic carried measured according to Recommendation ESO. No estimation is required. 4.2 Significant congestion Let Ac be the trajc carr
40、ied on the circuit group. Then, on the assumption that augmentation of the circuit group would have no effect on the mean holding time of calls carried or on the completion ratio of calls carried, the frajc ofered to the circuit group may be expressed as: where B is the present average loss probabil
41、ity for all call attempts to the considered circuit group, and W is a parameter representing the effect of call repetitions. Models for Ware presented in Annex A. To facilitate the quick determination of offered traffic according to the approximate procedure in Annex A, Table A. 1 including numerica
42、l values of the factor ( 1 - WB)/( 1 - B) was prepared for a wide range of B, H and r (for the definition of H and r, see Annex A). For the use of Table A. 1, see Note 2 in Annex A. NOTE 1 - Annex A gives a derivation of this relationship, and also describes a more complex model which may be of use
43、when measurements of completion ratios are available. NOTE 2 - When measurements of completion ratios are not available a W value may be selected from the range 0.6 to 0.9. It should be noted that a lower value of W corresponds to a higher estimate of traffic offered. Administrations are encouraged
44、to exchange the values of W that they propose to use. NOTE 3 - Administrations should maintain records of data collected before and after augmentations of circuit groups. This data will enable a check on the validity of the above formula, and on the validity of the value of Wused. NOTE 4 - In order
45、to apply this formula, it is normally assumed that the circuit group is in a fully operative condition or that any faulty circuits have been taken out of service. If faulty circuits or faulty transmission or signalling equipment associated with these circuits remain in service, then the formula may
46、give incorrect results. 2 Recommendation E.501 (05/97) 5 High-usage/final circuit group arrangement 5.1 High-usage group with no significant congestion on the final group 5.1.1 measurements on both circuit groups. Where a relation is served by a high-usage and final group arrangement, it is necessar
47、y to take simultaneous Let AH be the traffic carried on the high-usage group, and AF the traffic overflowing from this high-usage group and carried on the final group. With no significant congestion on the final group, the traffic offered to the high-usage group is: 5.1.2 Two distinct types of proce
48、dure are recommended, each with several possible approaches. The method given in 5.1.2.1 a) is preferred because it is the most accurate, although it may be the most difficult to apply. The methods of 5.1.2.2 may be used as additional estimates. 5.1.2.1 given for estimating AF, in decreasing order o
49、f preference: a) Simultaneous measurements are taken of AH and the total traffic carried on the final group. Three methods are AP is measured directly. In most circumstances this may be achieved by measuring traffic carried on the final group on a destination basis. The total traffic carried on the final group is broken down by destination in proportion to the number of effective calls to each destination. The traffic carried on the final group is broken down according to ratios between the bids from the high-usage groups and the total number of bids to the final group. b)
