1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 % TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%0(/.%G0G0.%47/2+G0G0!.$G0G0)3$.15!,)49G0G0/ii) combining of traffic streams on groups of terrestrial circuits which may be either high-usage or final choiceroutes;iii) detour routing of traffic between or
2、igin and destination countries to take advantage of prevailing low loadconditions on the detour path.In developing any such applications, account must be taken of the International Routing Plan(Recommendation E.171 1) and of accepted accounting principles (Recommendation D.150 2).It must be recogniz
3、ed that the preferred basis for dimensioning consists of traffic profiles based on real traffic.Nevertheless, many countries have found the standard profiles presented in this Recommendation very useful wherestreams are too small to obtain reliable measurements or where no measurements are available
4、.For both-way profiles, two equivalent methods of presentation are given in chart and tabular form. InFigure 1/E.523 hour-by-hour traffic volumes are shown in diagrammatically as percentages of the total daily trafficvolume; such percentages are particularly convenient for tariff studies. In Table 1
5、/E.523, hourly traffics are expressedas percentages of the busy hour traffic, and this is convenient for engineering purposes. Time zone differences aregiven in whole hours only. Directional profiles are given in Tables 2/E.523 and 3/E.523.Although tables are given for both-way and directional traff
6、ic streams, it must be emphasized that at this stageonly the both-way profiles can be regarded as soundly supported by measurement. The directional profiles aretheoretically based and supported by some measurements, but should be used with caution until adequate verificationhas been achieved.The the
7、oretical basis for the profiles presented here is contained in Annex A. It depends on a conveniencefunction f(t) which represents the profile of local daily traffic, where of course no time zone difference exists. Thefunction f(t) used for computation of the standard profile was derived by mathemati
8、cal manipulation of measurementsof the Tokyo-Oakland and Tokyo-Vancouver streams. Although these results have been supported by othermeasurements, it leaves open the possibility that the convenience function may vary from one country to another andthat, strictly, these should be derived independentl
9、y and then used to obtain a calculated profile for the internationalrelation. It also seems that the convenience function for the country of destination should be given greater weight thanthat for the country of origin. These remarks suggest possible refinements, but are not quantified in thisRecomm
10、endation.2 Fascicle II.3 - Rec. E.523 Fascicle II.3 - Rec. E.523 3Note 1 - The 24-hour profile of both-way traffic between any two countries is read from left to right from the appropriate row ofthe table; all time differences can be expressed in the range 0-12 hours. Each entry is expressed as a pe
11、rcentage of the busy hourtraffic.Note 2 - The more westerly country of a traffic relation is the one from which we can proceed eastwards to the other throughtime zones not exceeding 12 hours.Note 3 - For network planning studies, UTC (Universal Coordinated Time) would normally be used so that all tr
12、affic streams areprocessed time consistently. Clearly if the more westerly country is W hours ahead of UTC (ignoring the international dateline),then the traffic at 0000-0100 UTC is obtained from the row corresponding to the time difference between the two countries atthe column headed W. Alternativ
13、ely, the first entry in the appropriate row gives the relative traffic intensity for the hour (24- W)to (25- W).Example: For the traffic stream between the U.K. (UTC + 1 hour) and the central zone of USA (UTC + 18 hours), the timedifference is 7 hours and the USA is regarded as the more westerly cou
14、ntry, hence W= 18. Thus from the table, thetraffic during 0000-0100 UTC is 5 % of the busy hour traffic, and the busy hour is 1500-1600 UTC.Note 4 - The column headed “BH %” gives the busy hour traffic volume as a percentage of the daily traffic volume.4 Fascicle II.3 - Rec. E.523Note This table is
15、based on p = 1.4, q = 0.6, i.e. greater weight is given to the convenience function of the called party (seeAnnex A).Note This table is based on p = 1.4, q = 0.6, i.e. greater weight is given to the convenience function of the called party (seeAnnex A).Fascicle II.3 - Rec. E.523 5ANNEX A(to Recommen
16、dation E.523)Mathematical expression for the influence of time differenceson the traffic flowA telephone call is initiated when a person wishes to call someone else, but both parties have to be on the linebefore the call is established. It is considered that a telephone call is made at a time which
17、tends to be convenient forboth the calling and called parties. The degree of convenience for making a telephone call is considered to be aperiodical function of time t, whose period is 24 hours. When the time difference between both parties is zero, thedegree of convenience is denoted by f (t), wher
18、e t is local standard time. The graphic shape of the basic function f (t)will be determined by the daily pattern of human activities, and will resemble, or fairly closely coincide with, the hourby hour traffic distribution in the national (or local) telephone network.It is assumed that the hourly tr
19、affic distribution F(t), when a time difference of hours exists between theoriginating and called locations, is expressed as the geometric mean of convenience functions of two locations hoursapart:() () ()F t ft ft,/=+k12where() ( )k .+ hours=11224/ft ft dt(A-1)The sign of is positive when the time
20、at the destination is ahead of the reference time, and negative when thetime of destination is behind the reference time.The distribution of equation (A-1) represents the sum of the outgoing and incoming traffics. Expressions for theone-way hourly traffic distributions can also be obtained by extend
21、ing the concept of convenience function as follows.Define convenience functions both for the caller f0(t) and for the called party fi(t). Then the one-way trafficdistributions of east-bound and west-bound telephone calls, for the case of hour time-difference, are similarlyexpressed as follows:() ()
22、( )Ft ftfti,/east = k + 012() ( )k = / .+24 hours1012ft fti/dt(A-2)() () ( )Ft ftfti,/west 0= k + 12() ( )k = 1 / 24 hoursift f t dt. + / 012(A-3)wheret is the local standard time of the west station and is positive.6 Fascicle II.3 - Rec. E.523It is natural that a caller makes a call considering the
23、 convenience of the called person, and therefore theconvenience function of the called person fi contributes more than the convenience of the caller f0to the directionaldistribution F. They can be written as follows:() ()ft ftip= k 1, () ()ft ftq0 2= k ,(A-4)wherepq and p+q =2,and where k1and k2are
24、normalizing coefficients to ensure that:() = ,hoursftdti241() = .hoursftdt0241As to the values of p and q in equation (A-4), it has been found empirically that the convenience of the calledside p is considerably larger than that of originating side q, and appropriate values are roughly p = 1.4 andco
25、nsequently q = 0.6.References1 CCITT Recommendation International telephone routing plan, Rec. E. 171.2 CCITT Recommendation New system for accounting in international telephony, Rec. D.150.BibliographyCASEY(J. Jr.) and SHIMASAKI (N.): Optimal dimensioning of a satellite network using alternate rout
26、ing concepts,Sixth International Teletraffic Convention, Munich, 1970.RAPP (Y.): Planning of a junction network with non-coincident busy hours, Ericsson Technics, No. 1, 1971.CABALLERO (P. A.) and DIAZ (F.): Optimization of networks of hierarchical structure with non-coincident busyhours, Seventh International Teletraffic Convention, Stockholm, 1973.OTHA (T.): Network efficiency and network planning considering telecommunication traffic influenced by timedifference, Seventh International Teletraffic Convention, Stockholm, 1973.
