ITU-T Q 544-1988 DIGITAL EXCHANGE MEASUREMENTS《数字交换机测量》.pdf

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1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 1 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU$)4!,G0G0%8#(!.%3$)4!,G0G0%8#(!.%G0G0-%!352%-%.43)45G134G0G0RecommendationG0G01 (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation Q.544 was published in Fascicle VI.5 of the Blue Book. This file is an

2、extract fromthe Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below).2 In this Recommendation, the expression “Administrati

3、on” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic ormechanical, including photocopying and microfilm, w

4、ithout permission in writing from the ITU.Fascicle VI.5 - Rec. Q.544 1Recommendation Q.544Fascicle VI.5 - Rec. Q.544DIGITAL EXCHANGE MEASUREMENTS1 GeneralThis Recommendation applies to digital local, combined, transit and international exchanges for telephony inIntegrated Digital Networks (IDN) and

5、mixed (analogue/digital) networks, and also to local, combined, transit andinternational exchanges in an Integrated Digital Networks (ISDN). The field of application of this Recommendation ismore fully defined in Recommendation Q.500. Some measurements only apply to a certain type (or types) of exch

6、ange.Where this occurs, the application is defined in the text. Where no such qualification is made, the measurement appliesto all exchange applications.This Recommendation includes traffic and performance measurements that are necessary for provisioning andoperating exchanges so as to satisfy grade

7、 of service objectives covered in the E.500 series of Recommendations. Thesemeasurements are typically performed during specified periods and intervals after which the results are sent todesignated local and/or remote exchange terminals or operation and maintenance centres (OMC) or any otherappropri

8、ate data handling centre. In some cases, data may be utilized in its original form whereas in other cases data mayneed to be processed to determine when pre-set thresholds are exceeded and/or to recognize an abnormal condition whenit occurs. In this Recommendation, no particular system design requir

9、ement is implied. Different designs may have moreor less data accumulated and processed within the exchange or by an external system.Different types and sizes of exchanges may require different sets of measurements. Also, differentAdministrations may have different requirements for measurements depe

10、nding on policies, procedures or nationalnetwork considerations. An Administration may thus find it desirable in some applications to measure items that are notcovered by this Recommendation whereas in other applications some measurements may not be desired.Exchange measurements are required for bot

11、h national and international service. Requirements forinternational service take into consideration the following CCITT Recommendations: Recommendations E.401 to E.427: International telephone network management and checking of servicequality; Recommendations E.230 to E.277: Operational provisions r

12、elating to charging and accounting in theinternational telephone service.The aspects of traffic engineering are given in Recommendations E.500 to E.543. Recommendations on trafficmeasurements for SPC exchanges are provided by Recommendations E.502, E.503 and E.504.Additional measurements in an excha

13、nge, not specified in this Recommendation, are required, e.g. for: Transmission performance (Recommendations Q.551, Q.552, Q.553 and Q.554). Digital access signalling (Recommendations Q.920 to Q.931). This is for further study. Packet mode (Recommendations X.25 and X.75). This is for further study.

14、Signalling System No. 7 (e.g. those measurements specified in Recommendation Q.791 for the messagetransfer part require further study to determine their applicability to this Recommendation).Note For the terms and definitions of teletraffic used in this Recommendation, see Recommendation E.600.2 Mea

15、surement processes2.1 GeneralThe activities involved in exchange measurements can be split in four processes as represented byFigure 1/Q.544.2 Fascicle VI.5 - Rec. Q.544FIGURE 1/Q.544Measurement processesOn choice of each individual national Administration, the above four processes can be fully or p

16、artiallyintegrated into the exchanges.It is nevertheless recommended that:a) data collection be fully integrated into the exchange for all types of data;b) data presentation be integrated into the exchange and/or at the O traffic registration (traffic intensity and/or volume of traffic); call record

17、s registration.The data generated by event registration and traffic registration are suitable for direct utilization (immediatepresentation).Call records can only be utilized after off-line analysis. Processing of call records can generate any type ofdata, including the event registration and traffi

18、c registration.2.3 Bulk data storage, analysis and processingData storage for collected data can be required for accumulation of a massive data base suitable for subsequentanalysis and processing.These data can be held in the exchange for processing at the exchange location or transferred to adminis

19、trativeand engineering centres.2.4 Data presentationIt is the function through which the collected data are becoming readable. Features related to the datapresentation are:a) location of presentation;Fascicle VI.5 - Rec. Q.544 3b) time frame of presentation. It is dependent on the nature of the data

20、 and their utilization. The activities ofmaintenance and network management require immediate presentation;c) physical support of the displayed data and relevant format. These aspects are mainly related to the type ofdata and are to be left to individual implementations.3 Types of measurement dataMe

21、asurement data primarily consists of counts of various events and the traffic intensity on various resources.For certain measurement data, sampling, or time averaging techniques may provide an acceptably accurate result. Insome cases, externally generated test calls may provide the most practical me

22、thod of obtaining the data. In other cases,call records, such as detailed charging records, may be used.3.1 Event countsEvents, for example incoming seizures, call attempts encountering busy, and call attempts to specifieddestination codes should be countable. Some event counts may be accumulated ov

23、er the whole exchange whereas othersmay be accumulated only over a subset such as an inter-exchange circuit group. In some cases, event counts may beaccumulated several ways.3.2 Traffic intensityTraffic intensity on a pool of resources is the traffic volume divided by the duration of observation. It

24、 is thusequal to the average number of busy resources. As in the case of event counts, traffic intensity data may be for the wholeexchange or for various subsets.3.3 Call recordsCall records contain data used by the exchange for the setting up of calls. The data may include the identityand classific

25、ation of the originating line or incoming circuit, the dialled number, the call routing and disposition, andpossibly the time of occurrence of certain events during the entire call period.Call records can be generated and outputted by the exchange to allow the establishment of a data base suitablefo

26、r off-line processing to determine traffic values and characteristics. Output of the call records associated with astatistical sample of total calls may be sufficient for this purpose.4 Measurement administrationExchanges should provide capabilities for operating personnel to establish measurement s

27、chedules and directthe output routing of measurement results. The methods of establishing measurement schedules should be designed tominimize the introduction of errors when defining relevant parameters. It should be possible to have a number ofmeasurements simultaneously active with different sched

28、ules and output routings. A single measurement should becapable of having more than one measurement schedule and/or output routing simultaneously. The number ofmeasurement types running concurrently may be limited to conserve exchange storage and processing resources. Criteriafor measurement and rec

29、ording of traffic may be found in Recommendation E.500 and other related E-SeriesRecommendations.4.1 Scheduling4.1.1 Recording periodsA recording period is the time interval during which a measurement is performed. Measurements can beactivated either on-demand or according to a time schedule.Differe

30、nt measurement periods may be schedulable for different days of the week. For example, ameasurement may be scheduled for 0900 to 1800 on Monday through Friday and 0900 to 1200 on Saturday. Themeasurements for an entire week may be programmed and the weekly cycle may be repeated until a new command w

31、illstop it.4 Fascicle VI.5 - Rec. Q.5444.1.2 Result accumulation periodsA recording period contains one or more result accumulation periods. The beginning and ending of therecording period must correspond to the beginning and ending of result accumulation periods.The measurement result outputs are t

32、o be made available at the end of each result accumulation period andshall refer to that period.More than one result accumulation period may be required for an individual measurement.4.2 Data output criteria4.2.1 On scheduleMeasurement data output typically occurs shortly after the end of each resul

33、t accumulation period specified bythe measurement schedule. Alternatively, the exchange may store the data in its memory for limited periods, e.g. in theevent of contention for output resources.4.2.2 On demand(For further study.)4.2.3 On exceptionThe exchange should be able to provide measurement da

34、ta when specified criteria are met, for example, whenthe rate of incoming call attempts exceeds a particular value.4.3 Data output routing4.3.1 To a local or remote terminalMeasurement data should be able to be routed for printing or display on designated terminals which are eitherdirectly connected

35、 to the exchange or remotely connected via dedicated or switched circuits.4.3.2 To an external processing centreMeasurement data should be routable to external locations such as OMC that provide data collection andanalysis functions for multiple exchanges.4.3.3 To local storage mediaAn Administratio

36、n may require exchanges to store measurement data in bulk memories such as magnetic tapesfor later processing and analysis. This could be an alternative to sending the data to an OMC.4.4 PrioritiesHigh priority should be assigned to certain measurements that are essential, e.g. those associated with

37、collection and output of data used for overload detection, network management and accounting. These should not bediscontinued during periods of exchange processing congestion (see Recommendation Q.543, 3.8). Measurements thathave been suspended should be resumed in an order that is reverse to the or

38、der in which they were suspended.When recovery procedures are invoked, records associated with call accounting and billing should be retained.5 Application of measurements5.1 Planning and engineeringMeasurement data is essential for planning efficient telecommunication networks that meet specified g

39、rade-of-service standards. Analysis of data accumulated over a period of time provides information needed to forecast futuredemand and to plan and engineer extensions to the network.5.2 Operation and maintenanceOperation and maintenance functions are supported by the following types of measurement d

40、ata:Fascicle VI.5 - Rec. Q.544 5i) performance data pertaining to call handling irregularities and delays;6 Fascicle VI.5 - Rec. Q.544ii) availability data for the exchange, its subsystems, and its connecting subscriber lines and interexchangecircuits;iii) load on various components of the exchange.

41、The above data may be used to evaluate exchange and network performance and to plan rearrangements toimprove the service provided by the existing network equipment.5.3 Network managementData for network management includes certain traffic and performance measurements and status indications.These are

42、 used to detect abnormalities in the network and to automatically enable, or allow manual operation of,network management controls. In some cases, the data must be analyzed to determine whether specified thresholds arebeing exceeded. Since the effectiveness of network management actions depends upon

43、 their responsiveness to changingconditions in the network as a whole, it may be appropriate to perform this analysis by a data processing system servingone or more exchanges and display the results at a network management centre. Network management functions arecovered in Recommendations E.410 thro

44、ugh E.414 and Q.542.5.4 Accounting in international serviceAccounting in international service needs to be mutually agreed between Administrations; RecommendationsE.230 to E.277 apply.5.5 Subdivision of revenueSubdivision of revenue is a matter of agreement between RPOAs of the same country. Require

45、ments in thisarea are a national matter.5.6 Tariff and marketing studiesThe studies are intended to identify subscriber needs and trends. Requirements in this area are a nationalmatter.6 Call events definitionThis section is applicable to 64 kbit/s circuit switched call attempts. Application to othe

46、r types of calls orSupplementary Services is for further study.6.1 GeneralEvery call attempt coming from a subscriber line or interexchange circuit moves across a branch of thepossible status of call events reference diagram shown in Figure 2/Q.544.6.2 Call events detailed description6.2.1 Seizure f

47、rom a subscriber line or incoming circuitThis is the starting point for an incoming/outgoing call attempt.6.2.2 Valid addressThe incoming/originating seizure is successfully accepted by the exchange.6.2.3 Not routed call attemptA call attempt that is not routed through the exchange, perhaps due to a

48、n exchange condition or to receipt of anaddress that is incomplete or invalid.6.2.3.1 False startAn incoming seizure signal that has been recognized without being followed by digit reception.Fascicle VI.5 - Rec. Q.544 76.2.3.2 Incomplete dialling (time out, abandon)An incoming seizure that has been

49、received but the number of received digits is not sufficient to perform callrouting.6.2.3.3 Invalid addressAn attempt where the received digits do not correspond to an existing or allowed destination. The call is thengiven interception treatment (tone or announcements or operators).6.2.3.4 Call not routed due to the exchangeA call attempt where the system cannot perform call routing due to internal reasons (congestion):1) Blocking through the switching networkAlthough there is an outgoing circuit/subscriber line available for the required destination, the connectioncannot