џWPCL ћџ2BJ|xа АH аа АА X агга ХА6p&А6p&Х аеЮ† а Hр аааУ Уб cмˆ4 PŽТ б Fascicle II.3 Р-Р Rec. E.500 Ф ФPAGE1У Уб cмˆ4 PŽТ б ЮееЃ† а HH аааб cмˆ4 PŽТ бPAGE12У Уб cмˆ4 PŽТ б Fascicle II.3 Р-Р Rec. E.500 Ѓеа H№ ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаа X  аб cмˆ4 PŽТ бAll drawings appearing in this Recommendation have been done in Autocad. ‚У УRecommendation E.500 аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр(CСб cмˆ4 PŽТ бTRAFFIC INTENSITY MEASUREMENT PRINCIPLES аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ б1ТX ТIntroductionФ ФЦЦ 1.1С  СTraffic measurements provide the data base from which the planning, operation, management and, in some cases, accounting for transit considerations of the telephone network are carried out. Different applications may exist for the same traffic measurement. а H а1.2С  СThis Recommendation gives the principles for measuring carried traffic and bids on circuit groups and exchanges. The number of bids and preferably а H аalso carried traffic intensity should also be determined by individual relations (destinations). Data so obtained are applied both for operation and planning. Recommendation E.501 gives methods for estimating offered traffic from carried traffic measurements. Recommendation E.502 describes exchange requirements for traffic measurements both in national and international exchanges. Recommendation E.525 describes the traffic data analysis. Recommendation E.506 gives methods for forecasting future traffic requirements. The remainder of the E.500 Series of Recommendations describes how to utilize this data base in the operation and planning of telephone networks. а H аС СThe measurements required for network management as described in the E.410 Series are generally similar to those described in this Recommendation. They will usually require a variable and shorter reporting interval. ‚У У2ТX ТDefinitionsФ ФЦЦ а H аС СA У Уmeasurement of the amount of traffic carriedФ Ф is the average Erlang value during a certain period of time (e.g. 15 min., 1 hour). а H аС СA У Уmeasurement of the number of bidsФ Ф is a count of this entity during a certain period of time. а H аС СMeasurements are taken continuously during the day or with exclusion of known low traffic periods. The set of days at which measurement has been taken is called theУУ measurement daysФФ. С СIn the У Уyearly continuous measurementФ Ф the measurement days are postР-Рselected from a base period with a length of the whole year. The postР-Рselected days include the peak intensity values measured during the base period. С СIn the У Уyearly nonР-Рcontinuous measurementФ Ф the measurement days are scheduled (preР-Рselected) from a base period of a few months. The preР-Рselected days include the high load days of expectation or of earlier observations. С СA traffic profile is defined to beУУ stableФФ when the individual daily traffic profiles differ only little in shape and traffic volume between each other. С СA traffic profile is defined to beУУ unstableФФ when the individual daily traffic profiles differ in shape or traffic volume between each other. ‚У У3ТX ТOverviewФ ФЦЦ С СCircuit group dimensioning is based on a congestion objective, on the traffic intensity values at high load time and on the forecast value of intensity until the next augmentation of circuits. Intensity is measured during a daily busy hour and averaged over a number of days, to avoid exceptional values. а H аС СIf traffic measurements are taken every day of the year (yearly continuous measurements), the required averages can be calculated directly as described in РSР 4. If traffic measurements are taken only during a limited number of days in the year (yearly nonР-Рcontinuous measurements), the equivalent traffic loads may be estimated using the procedures given in РSР 5. а H аС СThe busy hour concept is an important aspect of teletraffic engineering and may be applied in a number of ways. In the E.500 Series of Recommendations the busy hour traffic used is an average of several days with, in some cases, an allowance for day to day variations (Recommendation E.521). а H аС СWithin the busy hour, traffic is considered to be stationary and thus the recorded intensity is the mean value during the busy hour. а H аС СThe recommended standard method of calculating the daily average requiresУУ continuouslyФФ measuring all quarter hours forУУ allФФ days concerned and selecting the busiest hour in the average profile for all days. This method is called the TimeР-РConsistent Busy Hour (TCBH) and is described in detail in РSР 6. This method is most valuable in situations of stable traffic profiles. The daily continuous measurements provide the data necessary for confirming profile stability. а H аС СAnother method of arriving at the representative average busy hour also involvesУУ continuouslyФФ measuring all quarter hours, but only the busiest hour ofУУ each dayФФ is retained for averaging. This method is called the Average Daily Peak Hour (ADPH) and is described in detail in РSР 6 together with the relation of ADPH results to TCBH results. С СThe advantages of ADPH are that it requires less data storage and manipulation than TCBH and that it gives a more representative value in the situation of unstable traffic profiles. а H аС СIn some situations Administrations do not measure trafficУУ continuouslyФФ over the day, but only for the hour or few hours expected to be busiest. This method is called the Fixed Daily Measurement Period (FDMP) or Fixed Daily Measurement Hour (FDMH) and is described in detail in РSР 7 together with the relation of FDMP results to TCBH results. а H аС СThe advantage of FDMP is that it requires less measurement resources than TCBH or ADPH. The disadvantage is that in individual situations the difference between FDMP and TCBH results may vary widely. а H аС СIn some network situations significant savings can be made by multihour dimensioning (e.g. cluster engineering, time zone differences). This requires daily continuous measurements. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС‚У У4С  Сб cмˆ4 PŽТ бYearly continuous measurementsЦЦ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФ ФС СTraffic statistics should be measured for the significant period of each day of the whole year. The significant period may in principle be 24 hours of the day. С СThe measurements for computing normal traffic load should be the 30 highest days in a fixed 12Р-Рmonth period. Normally these will be working days, but in some cases separate weekend or tariffР-Рrelated period measurements should be examined so that Administrations can agree bilaterally on appropriate measures to maintain a reasonable grade of service (GOS) for weekends and tariffР-Рrelated periods. Recurring exceptional days (e.g. Christmas, Mother's Day, etc.) should be excluded for network dimensioning purposes although the data should be collected for network management purposes (Recommendation E.410). This method gives traffic information of relatively high accuracy and is suitable for circuits groups operated automatically or semiautomatically. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС4.1С   Сб cмˆ4 PŽТ бУУNormal and high load levelsЦЦ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СTeletraffic performance objectives and dimensioning practices generally set objectives for two sets of traffic load conditions. а H аС СA normal traffic load can be considered the typical operating condition of a network for which subscribers service expectations should be met. С СA high traffic load can be considered a less frequently encountered operating condition of a network for which normal subscriber expectations would not be met but for which a reduced level of performance should be achieved to prevent excessive repeat calling and spread of network congestion. С СIn order to estimate normal and high load levels, offered traffic intensity values should, where necessary, be estimated from daily carried traffic measurements. Estimation procedures are presented in Recommendation E.501. С СNormal and high loads are defined in Table 1/E.500. ‚Ср SСб cмˆ4 PŽТ бTABLE 1/E.500 б cмˆ4 PŽТ баЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH€шP Ш xа(€и0ˆрР!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр RСааб cмˆ4 PŽТ бCircuit groups а РА ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџР€шP Ш xа(€и0ˆрР!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ ба РА аб cмˆ4 PŽТ бвЦƒР@ И €јР!Цв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџР€шP Ш @ џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСрРLСб cмˆ4 PŽТ бParameter аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџРˆxрHР€џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСрРKСNormal load аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџРШ0˜ˆX Р!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСрРLСHigh loadд k+дŒа јА ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџјШ0˜ˆX Р!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бˆа јА аб cмˆ4 PŽТ бвЦƒР@ И €јР!Цв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ€шP Ш @ јџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бCarried traffic intensity а јx ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџˆxрHР€јџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаMean of the 30 highest working days during a 12Р-Рmonth period. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџјШ0˜ˆX Р!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаMean of the five highest days in the same period as normal load. а јА аб cмˆ4 PŽТ бˆа јА аб cмˆ4 PŽТ бвЦƒР@ И €јР!Цв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ€шP Ш @ јџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бNumber of bids а јр ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџˆxрHР€јџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаMean of the same 30 days on which the offered traffic intensities are highest. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџјШ0˜ˆX Р!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаMean of same five days on which the offered traffic intensities are the highest. а јА аб cмˆ4 PŽТ бˆа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа б cмˆ4 PŽТ баЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH€шP Ш xа(€и0ˆрР!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа‚Ср8NСб cмˆ4 PŽТ бExchanges а РА ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџР€шP Ш xа(€и0ˆрР!џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ ба РА аб cмˆ4 PŽТ бвЦƒР@ И €јР!Цв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџР€шP Ш @ џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСрРLСб cмˆ4 PŽТ бParameter СрРKСNormal load СрРLСHigh load а јА ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ€шP Ш @ јџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бˆа јА аб cмˆ4 PŽТ бвЦƒР@ И €јР!Цв‡б cмˆ4 PŽТ бCarried traffic intensity а јh аMean of the ten highest days during a 12Р-Рmonth period. Mean of the five highest days in the same period as normal load. а јА аб cмˆ4 PŽТ бˆа јА аб cмˆ4 PŽТ бвЦƒР@ И €јР!Цв‡б cмˆ4 PŽТ бNumber of bids а јh аMean of the same ten highest days (not necessarily the same as the highest offered traffic days) during a 12Р-Рmonth period. Mean of the five highest days (not necessarily the same as the highest offered traffic days) in the same period as normal load. а јА аб cмˆ4 PŽТ бˆа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТУ У5СјСб cмˆ4 PŽТ бYearly nonР-Рcontinuous measurementsФ ФЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ б5.1Тh  ТУУIntroductionЦЦ а H аФФС СThis method consists in taking measurements on a limited sample of days in each year. Limited sample measurements will normally be taken on working days, but Administrations may agree bilaterally to measure weekend or reduced tariff periods separately. а H аС СAny Administration proposing to use a yearly nonР-Рcontinuous measurement procedure is advised to confer with other end Administrations to ensure that the maximum information is available to assist in the choice of measurement days. For example, if the other end Administration has continuous measurement capability it may be possible to identify busy seasons or consistent lowР-Рtraffic days. а H аС СTable 2/E.500 shows the results of a study carried out on circuit groups within a large metropolitan network [1]. The errors shown are the underР-Рestimates resulting if average busy hour carried traffic intensity is measured over a preР-Рdefined twoР-Рweek period of the year, rather than the actual busiest twoР-Рweek period. (The preР-Рdefined period was, in fact, the peak period of the preceding year.) а H аС СThe error averages 7.6% more or less, depending on circuit group size. Had an Administration wished to estimate the true peak twoР-Рweek intensity with 90% confidence, starting with the preР-Рdefined twoР-Рweek measurements, the latter would have had to be increased by amounts ranging from about 14% for large circuit groups, up to about 31% for small ones. (The magnitude of these corrections indicates how inadequate a twoР-Рweek sample can be as a basis for network planning.) ‚Ср SСб cмˆ4 PŽТ бTABLE 2/E.500 а H аУ УWeighted mean error and the upper limit of the intensity error class for a cumulative proportion of circuit groups, categorized according to traffic intensityФ Ф б cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH` Ш 0 ˜ ˆџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ б Ср WСTotal Ср WСLow Ср UС< 10 Erl Ср VСMedium Ср TС10Р-Р100 Erl Ср WСHigh Ср UС> 100 Erl а 0ј ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡а 08 аб cмˆ4 PŽТ бCircuit groups аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр:xС 2728 Ср:xС 1056 Ср:xС 1564 Ср:xС 110 а 0ј аб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡а 0h ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бWeighted mean error of the intensity value аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр:р†С 7.6% Ср:р†С 13.7% Ср:р†С 7.8% Ср:р†С 5.2% а 0ј аб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡а 0x ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бCumulative proportion of circuit groups аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа а 0ј аб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бС:Ј;СС; <СС<˜=С50% аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр:˜yС 7.9% Ср:˜xС 12.9% Ср:˜xС 6.9% Ср:˜xС 3.9% а 0ј аб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бС:Ј;СС; <СС<˜=С80% аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр:˜yС16.9% Ср:˜xС 22.9% Ср:˜xС 17.9% Ср:˜xС 7.9% а 0ј аб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бС:Ј;СС; <СС<˜=С90% аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр:˜yС23.9% Ср:˜xС 30.9% Ср:˜xС 23.9% Ср:˜xС 13.9% а 0ј аб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бС:Ј;СС; <СС<˜=С95% аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр:˜yС31.9% Ср:˜xС 37.9% Ср:˜xС 34.9% Ср:˜xС 17.9% а 0ј аб cмˆ4 PŽТ бˆа 0ј аб cмˆ4 PŽТ бвЦ…ˆH8€јИ0xЦв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˆ0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бС:Ј;СС; <СС<˜=С98% аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџаР(0џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр:˜yС41.9% Ср:˜xС 47.9% Ср:˜xС 40.9% Ср:˜xС 26.9% а 0ј аб cмˆ4 PŽТ бˆа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТа Т5.2СpСУУEstimation methodЦЦ а H аФФС СAn approximate statistical method for estimating normal and high load levels from limited sample measurements is provided below. Та ТС€ HС5.2.1С СУУPrinciple of estimation methodЦЦ а H аФФС СMeasurements are taken on a limited sample of days, and the mean (УУMФФ) and standard deviation (УУSФФ) of the daily busy hour traffic loads are calculated. Normal and high load level estimates (УУLФФ) are given by: аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHp8А"(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ Ьа‚УУС СС pССШ8#СLƒФФ =УУ MФФ +УУ kФФ .УУ SФФ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаdifferent values of the factorУУ kФФ being used for normal and high load levels.д Д-дŒаЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHp8А"(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ Ьа‚УУС СС pССШ8СSƒФФ = eq \b\bc\[ (\f( 1,УУnФФР-Р1)УУ niФФ=1 (УУXУУiФФФФ Р-РУУ MФФ)УУб cмˆ4 PŽТ б2б cмˆ4 PŽТ бФФ)УУб cмˆ4 PŽТ б1/2б cмˆ4 PŽТ бФФ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаwhere а H аТа ТТ№ ТС€ СУУXУУiФФФФ is the timeР-Рconsistent busy hour traffic measured on theУУ iФФth day,ЦЦ Та ТТ№ ТС€ СУУMФФ =eq \f( 1,УУnФФ) \i\suУУб cмˆ4 PŽТ б(i=1,n,)б cмˆ4 PŽТ б XУУб cмˆ4 PŽТ бiб cмˆ4 PŽТ бФФФФ is the sample mean, andЦЦ Та ТТ№ ТС€ СУУnФФ is the number of measurement days.ЦЦ а H аС СIf the measurement period is less than 30 days then the estimate will not be very reliable. In this case Administrations should, if possible, carry out special measurement studies to determine typical values of the standard deviation (e.g. as a function of the sample mean). Та ТС€ HС5.2.2С СУУBase period for measurementsЦЦ а H аФФС СIt is important to determine the Р"Рbase periodР"Р since the length of this period influences the values assigned to the multiplication factorsУУ kФФ. С СThe base period is the set of valid days in each year from which measurement days are preselected. This period should include all days which are potential candidates for being among the 30 highest days (but excluding recurring exceptional days Р-Р see РSР 4). С СThe base period may be restricted to a busy season (which need not necessarily comprise a set of consecutive weeks) provided that the traffic is known to be consistently higher during this period than during the remainder of the year. а H аС СThe base period may be the whole year, but Administrations may also decide to exclude known lowР-Рtraffic days. Та ТС€ HС5.2.3С СУУSelection of measurement daysЦЦ а H аФФС СMeasurement days should be distributed reasonably evenly throughout the base period. If the base period extends over the whole year then the measurement sample should include some days from the busiest part of the year, if these are known. The limited sample should comprise at least 30 days to ensure reliable estimates. If this is not possible, then a minimum of 10 measurement days may be used. In this case the reliability of the estimate is poor. Та ТС€ HС5.2.4С СУУMultiplication factorsЦЦ а H аФФС СMultiplication factorsУУ kФФ for 5Р-Рday, 10Р-Рday, and 30Р-Рday load levels are given by the curves in Figure 1/E.500, as a function of the number of days in the base period. These factors are derived from tables of order statistics from the normal distribution [2]. а H аС СWhen the base period extends over the whole year these factors may not always be reliable because of the effects of differing seasonal patterns. Individual Administrations may then prefer to use different values for the factors, if they have obtained more precise information from special measurement studies. ‚Ср LСб cмˆ4 PŽТ бFigure 1/E.500 Љ CCITT64220 б cмˆ4 PŽТ б Та ТС€ HС5.2.5С СУУExampleЦЦ а H аФФС СThe following data illustrate the application of this procedure to the estimation of normal and high load levels from nonР-Рcontinuous measurements on a circuit group over a 1Р-Рyear period. С СAfter excluding holidays and other known low traffic periods the base period which is available for measurement purposes is determined to be 220 days. TheУУ kФФР-Рfactors to be used are therefore (from Figure 1/E.500): С СNormalСи С(30Р-Рday) load level:УУ kФФ = 1.6 С СHighСи С( 5Р-Рday) load level:УУ kФФ = 2.3 С СMeasurements are taken on 50 days within the base period. The daily measured busyР-Рhour traffic values, in Erlangs, are as follows: б cмˆ4 PŽТ бвЦŠp` @ И ˜ №рH8 pшШ@ xЦв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH` Ш 0 ˜ џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа‚Ср WСб cмˆ4 PŽТ б21.5 Ср WС 20.5 Ср WС 18.7 Ср WС 15.0 Ср WС 18.4 Ср WС 21.6 Ср WС 18.1 Ср WС 24.2 Ср WС 26.7 Ср WС 22.1 а ј ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бˆа ј аб cмˆ4 PŽТ бвЦŠp` @ И ˜ №рH8 pшШ@ xЦв‡а  аСр>x€Сб cмˆ4 PŽТ б 21.8 Ср>x€С 17.8 Ср>x€С 17.2 Ср>x€С 19.8 Ср>x€С 15.2 Ср>x€С 20.4 Ср>x€С 16.7 Ср>x€С 20.6 Ср>x€С 23.1 Ср>x€С 23.5 а ј аб cмˆ4 PŽТ бˆа ј аб cмˆ4 PŽТ бвЦŠp` @ И ˜ №рH8 pшШ@ xЦв‡а  аСр>x€Сб cмˆ4 PŽТ б 19.6 Ср>x€С 18.1 Ср>x€С 21.3 Ср>x€С 15.9 Ср>x€С 15.9 Ср>x€С 17.8 Ср>x€С 17.4 Ср>x€С 20.9 Ср>x€С 25.9 Ср>x€С 20.6 а ј аб cмˆ4 PŽТ бˆа ј аб cмˆ4 PŽТ бвЦŠp` @ И ˜ №рH8 pшШ@ xЦв‡а  аСр>x€Сб cмˆ4 PŽТ б 20.9 Ср>x€С 19.2 Ср>x€С 17.6 Ср>x€С 12.9 Ср>x€С 14.2 Ср>x€С 18.1 Ср>x€С 16.9 Ср>x€С 24.2 Ср>x€С 22.2 Ср>x€С 26.8 а ј аб cмˆ4 PŽТ бˆа ј аб cмˆ4 PŽТ бвЦŠp` @ И ˜ №рH8 pшШ@ ˜xЦв‡а  аСр>x€Сб cмˆ4 PŽТ б 22.5 Ср>x€С 22.8 Ср>x€С 19.3 Ср>x€С 19.1 Ср>x€С 18.7 Ср>x€С 19.8 Ср>x€С 18.0 Ср>x€С 26.0 Ср>x€С 22.5 Ср>x€С 27.5 а ˜ј ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџ` Ш 0 ˜ ˜џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бˆа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаС СThe sample mean and standard deviation are: Та ТТ№ ТС€ СУУMФФ = 20.11ЦЦ Та ТТ№ ТС€ СУУSФФ = 3.37ЦЦ а H аС СThe normal and high load level estimates are then calculated fromУУ LФФ =УУ MФФ +УУ kФФ .УУ SФФ to give: Та ТТ№ ТС€ СNormal loadСЈ С= 25.5 ErlangsЦЦ Та ТТ№ ТС€ СHigh loadСЈ С= 27.9 ErlangsЦЦ а HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС5.2.6С јСб cмˆ4 PŽТ бУУHigh to normal traffic ratiosЦЦ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СIn some circumstances, actual values of high day loads are not available. In such cases, various Administrations use standard ratios of high to normal load for forecasting for design or planning purposes. а H аС СFor example, as a general order of magnitude, the following ratios of high to normal load may be used as a guide for a healthy network: вЦƒH   Цв‡УУС СParameterФФ УУCircuit groupsФФ УУExchangesФФ ˆвЦƒH   Цв‡С СOffered traffic intensity 1.2 1.1 ˆвЦƒH   Цв‡С СNumber of call attempts 1.4 1.2 ˆа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТ‚У У6СјСб cмˆ4 PŽТ бDaily continuous measurementsФ ФЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ б6.1Тh  ТУУMeasurementЦЦ а Hh аФФС СIt is recommended that Administrations take traffic measurements continuously over the day throughout the measurement period. а H аС СDepending on the application, a busy hour value for dimensioning should be calculated as the peak value of the mean day profile or the average of daily peak values. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС6.2С   Сб cмˆ4 PŽТ бУУTimeР-Рconsistent busy hour (TCBH)Р-Рintensity (postР-Рselected)ЦЦ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаФФб cмˆ4 PŽТ бС СFor a number of days, carried traffic values for each quarter hour for each day are recorded. The values for the same quarter hour each day are averaged. а H аС СThe four consecutive quarterР-Рhours in this average day which together give the largest sum of observed values form the TCBH with its TCBHР-Рintensity. This is sometimes referred to as postР-Рselected TCBH. а H аС СIn the case where a stable traffic profile exists, the TCBHР-Рintensity is used as a base method for dimensioning; if measurement methods yielding systematically lower or higher intensity values than the TCBHР-Рmethod are used, adjustments to the calculations are needed. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС6.3С   Сб cмˆ4 PŽТ бУУAverage of the daily peak hours traffic, defined on quarter hour or on full hour basisЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СTo find the average of daily peak quarterly defined hour (ADPQH) intensity, the traffic intensity is measured continuously over a day in quarterР-Рhour periods. The intensity values are processed daily to find out the four consecutive quarter hours with the highest intensity value sum. Only this daily peak hour traffic intensity value is registered. The average is taken over a number of working days peak intensities. The timing of peak intensity normally varies from day to day. а H аС СTo find the average of daily peak full hour (ADPFH) intensity, the traffic intensity is measured continuously over a day in fullР-Рhour periods. Only а H аthe highest of these intensity values is registered. The average is taken over a number of days peak intensities. а H аС СThe comparative measurements have shown that the traffic intensity values measured by the ADPFHР-Рmethod, are very consistent with the values measured by the TCBHР-Рmethod, whereas the ADPQHР-Рmethod yields slightly (a few percent) higher values. (See Annex A.) ADPH has an advantage over TCBH when traffic profiles are unstable. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС6.4С   Сб cмˆ4 PŽТ бУУAlternate routing networksЦЦ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СWhen alternate routing is used, the dimensioning methods in Recommendation E.522 should be applied (multiР-Рhour dimensioning technique). In general this requires the continuous measurement of a 24Р-Рhour profile for each traffic quantity in the alternative routing cluster. С СIn Annex A the differences in results between busy hours defined for individual circuit groups and for clusters indicate the advantage of continuous measurements and multiР-Рhour dimensioning for alternative routing networks. а H аС СIn circumstances where the traffic profiles are stable and similar in the whole cluster, the multiР-Рhour dimensioning may be applied on a few selected hours of significance to the entire cluster. The stability of traffic profiles must be confirmed. ‚У У7ТX ТDaily nonР-Рcontinuous measurementsФ ФЦЦ 7.1Тh  ТУУMeasurementЦЦ а H аФФС СSome Administrations may find it necessary or economically attractive to restrict measurements to a few hours or only one hour per day. Such measurements will always be less accurate than continuous measurements. The resulting busy hour values will always be less than or equal to TCBH. а H аС СThe time of fixed daily measurements should be confirmed several times a year by measurement of the full daily traffic profile for every circuit group. The measurement can cover several periods daily, as well. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС7.2С   Сб cмˆ4 PŽТ бУУFixed daily measurement period (FDMP)ЦЦ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СWith this method measurements are taken within a fixed period (e.g. of 3 hours) each day. This period should correspond to the highest part of the traffic profile, which is expected to include the TCBH. Measurement values are accumulated separately for each quarterР-Рhour, and the busiest hour is determined at the end of the measurement period, as for the TCBH. This method will normally give results which are about 95% of the TCBH traffic level, when the time of fixed daily measurement is defined for every single circuit group, although major changes in the traffic profile could lead to larger errors. а H аС СIn alternate routing networks with traffic profiles that are similar and stable in the whole cluster, FDMP may be used to produce measurements for multiР-Рhour dimensioning applied on a few selected hours of significance. The stability of traffic profiles should be confirmed several times a year. Та Т7.3СpСУУFixed daily measurement hour (FDMH)ЦЦ а H аФФС СIf the fixed daily measurement period is reduced to 1 hour, then it is only necessary to accumulate a single measured value from each day. This is the simplest measurement method, and it will normally give results which are about 90% of the TCBH traffic value, when the time of the fixed daily measurement is defined for single circuit groups individually. However, the variations around the average are large. ‚У У8ТX ТFlow chart for the application of the different calculation methodsФ ФЦЦ С СThe decisions represented in Figure 2/E.500 compare measurement and analysis costs to variations in the results for a single circuit group or cluster. The costs are particular to each Administration. С СThe preceding sections of this Recommendation indicate the amount of measurement variance that can occur in typical situations which can result in overprovisioning or a risk of poor grade of service. С СIn cluster engineering for alternative routing networks, measurements outside the busy hour are normally needed if the traffic profile is unstable. In situations of stable traffic load the significant traffic hours can be predicted accurately, allowing use of a FDMP method. ‚Ср KСб cмˆ4 PŽТ бFigure 2/E.500 Љ T0200810Љ87 б cмˆ4 PŽТ б Ср VСб cмˆ4 PŽТ бANNEX A Ср MСб cмˆ4 PŽТ б(to Recommendation E.500) аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр <СУ УExample ofб cмˆ4 PŽТ б influence of different busy hour definitions on Ср LСmeasured traffic intensity аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФ ФA.1Тh  ТУУIntroductionЦЦ ФФС СThe influence of different busy hour definitions on measured traffic intensity has been investigated by means of measurements on real traffic outgoing from an international exchange. а H аС СThree clusters with a total of 15 circuit groups have been studied. One of the clusters (Cluster 1) carries traffic between different time zones. С СTraffic per quarter of an hour was measured during the whole day in 5 twoР-Рweek periods (10 consecutive working days). The total elapsed time covered 9 months. С СFrom the results of the first twoР-Рweek period of daily continuous measurements the times of FDMH and FDMP have been determined: Та ТР-РТ№ Тfor each circuit group individually (ind),ЦЦ Та ТР-РТ№ Тper cluster (clu), andЦЦ Та ТР-РТ№ Тfor all three clusters commonly (com).ЦЦ а H аС СThe time of FDMH is equal to the time of TCBH in the first twoР-Рweek period. FDMP includes FDMH and the hour before and the hour after. A.2Тh  ТУУResults of measurementsЦЦ ФФС СThe results of the measurements undertaken are summarized in Figures AР-Р1/E.500 to AР-Р5/E.500. а H аС СFigure AР-Р1/E.500 shows how the starting time of TCBH varies between the five measurement periods: Та ТР-РТ№ Тfor each cluster, andЦЦ Та ТР-РТ№ Тfor individual circuit groups in each cluster.ЦЦ а H аС СThe following observations on the starting time of TCBH can be made: а H аТа ТР-РТ№ Тthe starting time of TCBH is the same in not more than 2 periods. This refers to both circuit groups and clusters;ЦЦ а H аТа ТР-РТ№ Т5 circuit groups and 1 cluster have different TCBH in all periods;ЦЦ а H аТа ТР-РТ№ Т8 circuit groups and 2 clusters have TCBH within the same part of the day (morning or evening) in all periods;ЦЦ а H аТа ТР-РТ№ ТTCBH common to all clusters is in the evening in all periods. Only 2 periods have the same common TCBH.ЦЦ а Hx аС СIn Figures AР-Р2/E.500 to AР-Р5/E.500 traffic intensities according to different busy hour definitions have been compared. Traffic intensity according to the TCBH definition has been used as reference value (corresponding to 100% in the figures). а H аС СFigure AР-Р2/E.500 shows the results of comparisons on a cluster level, and Figures AР-Р3/E.500 to AР-Р5/E.500 on a circuit group level. С СMeans and variations of traffic intensities are given as: Та ТР-РТ№ Тan average of all five periods (ADPQH and ADPFH), andЦЦ а H аТа ТР-РТ№ Тan average of measurement periods 2, 3, 4 and 5 compared with period 1 (FDMH and FDMP).ЦЦа HH а Та ТA.3СpСУУResults on cluster level (Figure AР-Р2/E.500)ЦЦ Та ТТ№ ТС€ СФФADPQHСи ССЈ Сintensities over 100%, mean = 102%.ЦЦ Та ТТ№ ТС€ СADPFHСи ССЈ Сintensities around 100%, mean = 100%.ЦЦ Та ТТ№ ТС€ СFDMPУУУУcluФФФФСP Сintensities from 95 to 100%, mean = 99%.ЦЦ Та ТТ№ ТС€ СFDMHУУУУcluФФФФСP Сintensities from 90 to 98%, mean = 94%.ЦЦ Та ТТ№ ТС€ СFDMPУУУУcomФФФФСP Сintensities from 42 to 100%, mean = 89%.ЦЦ Та ТТ№ ТС€ СFDMHУУУУcomФФФФСP Сintensities from 35 to 93%, mean = 83%.ЦЦ а HX аA.4Тh  ТУУResults on circuit group level (Figures AР-Р3/E.500 to AР-Р5/E.500)ЦЦ Та ТТ№ ТС€ СФФADPQHСи ССЈ Сintensities over 100%, mean = 104%.ЦЦ Та ТТ№ ТС€ СADPFHСи ССЈ Сintensities around 100%, mean = 100%.ЦЦ Та ТТ№ ТС€ СFDMPУУУУindФФФФСP Сintensities from 88 to 100%, mean = 99%.ЦЦ Та ТТ№ ТС€ СFDMHУУУУindФФФФСP Сintensities from 80 to 100%, mean = 93%.ЦЦ Та ТТ№ ТС€ СFDMPУУУУcluФФФФСP Сintensities from 51 to 100%, mean = 98%.ЦЦ Та ТТ№ ТС€ СFDMHУУУУcluФФФФСP Сintensities from 45 to 99%, mean = 91%.ЦЦ Та ТТ№ ТС€ СFDMPУУУУcomФФФФСP Сintensities from 24 to 100%, mean = 89%.ЦЦ Та ТТ№ ТС€ СFDMHУУУУcomФФФФСP Сintensities from 14 to 99%, mean = 81%.ЦЦ а HH а‚Ср8CСб cмˆ4 PŽТ бFigure AР-Р1/E.500 Љ T0200820Љ87 б cмˆ4 PŽТ б Ср8CСб cмˆ4 PŽТ бFigure AР-Р2/E.500 Љ T0200830Љ87 б cмˆ4 PŽТ б Ср8CСб cмˆ4 PŽТ бFigure AР-Р3/E.500 Љ T0200840Љ87 б cмˆ4 PŽТ б Ср8CСб cмˆ4 PŽТ бFigure AР-Р4/E.500 Љ T0200850Љ87 б cмˆ4 PŽТ б Ср8CСб cмˆ4 PŽТ бFigure AР-Р5/E.500 Љ T0200860Љ87 б cмˆ4 PŽТ б У УС СReferencesФ Ф а H а[1]Тh  ТPARVIALA (A.): The stability of telephone traffic intensity profiles and its influence on measurement schedules and dimensioning (with Appendix). 11th International Teletraffic Congress, Kyoto 1985.ЦЦ а H а[2]Тh  ТBiometrika Tables for Statisticians, Table 9, Vol. 2.УУ Cambridge University PressФФ, 1972.ЦЦ