The worldwide nature of the international telephone network, spanning as it does all possible time zones, has stimulated studies of the traffic streams between countries in different relative time locations. These studies have led to the development of standardized 24-hour traffic profiles which, theoretically based and verified by measurements, would be useful for engineering purposes. In fact, these concepts can be applied to a variety of network situations.
ITU-T E.523 SPANISH-1993 Referenced Document
ITU-T D.150 New System for Accounting in International Telephony - Series D: General Tariff Principles - Charging and Accounting in the International Telephone Service Study Group 3; 21 pp*， 1999-06-01 Update
ITU-T E.171 International Telephone Routing Plan (Study Group II)
ITU-T E.523 STANDARD TRAFFIC PROFILES FOR INTERNATIONAL TRAFFIC STREAMS