1、 International Telecommunication Union ITU-T D.156TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 2(09/2012) SERIES D: GENERAL TARIFF PRINCIPLES General tariff principles Charging and accounting in the international telephone service Network externalities Amendment 2: New Annex B Determina
2、tion of the network externality premium Recommendation ITU-T D.156 (2008) Amendment 2 ITU-T D-SERIES RECOMMENDATIONS GENERAL TARIFF PRINCIPLES TERMS AND DEFINITIONS D.0 GENERAL TARIFF PRINCIPLES Private leased telecommunication facilities D.1D.9 Tariff principles applying to data communication servi
3、ces over dedicated public data networks D.10D.39 Charging and accounting in the international public telegram service D.40D.44 Charging and accounting in the international telemessage service D.45D.49 Principles applicable to GII-Internet D.50D.59 Charging and accounting in the international telex s
4、ervice D.60D.69 Charging and accounting in the international facsimile service D.70D.75 Charging and accounting in the international videotex service D.76D.79 Charging and accounting in the international phototelegraph service D.80D.89 Charging and accounting in the mobile services D.90D.99 Charging
5、 and accounting in the international telephone service D.100D.159Drawing up and exchange of international telephone and telex accounts D.160D.179 International sound- and television-programme transmissions D.180D.184 Charging and accounting for international satellite services D.185D.189 Transmissio
6、n of monthly international accounting information D.190D.191 Service and privilege telecommunications D.192D.195 Settlement of international telecommunication balances of accounts D.196D.209 Charging and accounting principles for international telecommunication services provided over the ISDN D.210D
7、.269 Charging and accounting principles for next generation networks (NGN) D.270D.279 Charging and accounting principles for universal personal telecommunication D.280D.284 Charging and accounting principles for intelligent network supported services D.285D.299 RECOMMENDATIONS FOR REGIONAL APPLICATI
8、ON Recommendations applicable in Europe and the Mediterranean Basin D.300D.399 Recommendations applicable in Latin America D.400D.499 Recommendations applicable in Asia and Oceania D.500D.599 Recommendations applicable to the African Region D.600D.699 For further details, please refer to the list of
9、 ITU-T Recommendations. Rec. ITU-T D.156 (2008)/Amd.2 (09/2012) i Recommendation ITU-T D.156 Network externalities Amendment 2 New Annex B Determination of the network externality premium Summary Amendment 2 to ITU-T D.156 (2008) introduces Annex B, which presents a method to calculate the network e
10、xternality premium. History Edition Recommendation Approval Study Group 1.0 ITU-T D.156 2008-10-30 3 1.1 ITU-T D.156 (2008) Amd. 1 2010-05-21 3 1.2 ITU-T D.156 (2008) Amd. 2 2012-09-07 3 ii Rec. ITU-T D.156 (2008)/Amd.2 (09/2012) FOREWORD The International Telecommunication Union (ITU) is the United
11、 Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendat
12、ions on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approv
13、al of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administratio
14、n“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance
15、 with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is req
16、uired of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intelle
17、ctual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. H
18、owever, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the
19、 prior written permission of ITU. Rec. ITU-T D.156 (2008)/Amd.2 (09/2012) iii Table of Contents Page B.1 Introduction 1 B.2 Methodology . 1 B.3 Results 3 B.4 Conclusion 4 Rec. ITU-T D.156 (2008)/Amd.2 (09/2012) 1 Recommendation ITU-T D.156 Network externalities Amendment 2 New Annex B Determination
20、of the network externality premium (This annex forms an integral part of this Recommendation.) B.1 Introduction The need to take into account network externalities in the development of telecommunications has been under discussion in ITU-T and the regional tariff groups for a number of years. This d
21、iscussion led in 2008 to the adoption of an appendix to Recommendation ITU-T D.156, the purpose of which is to ensure payment of network “externality“ premiums by the developed countries to the developing countries in order to facilitate rapid development of telecommunication networks in the former.
22、 The main purpose of these externality premiums is to reduce the digital divide and ensure access for all, as stipulated by Resolution 22 of the ITU Plenipotentiary Conference (Rev. Antalya, 2006). The adoption of Recommendation ITU-T D.156 at the WTSA was conditional on the development of two addit
23、ional appendices to facilitate implementation. The first of these, concerning prudential measures, was adopted in 2010 at the meeting of ITU-T Study Group 3 in Seoul, Republic of Korea; the second, concerning determination of the premium, on which work has just been completed, is the subject of this
24、 amendment. This amendment focuses on two main points: methodology and an analysis of the results. B.2 Methodology Two approaches are considered in this Recommendation. It is necessary first of all to show the existence of network effects by VAR modelling and then to evaluate the associated external
25、ity premium. B.2.1 VAR model This is done in two stages: unit root tests and Granger tests. a) Exploring a relationship between the values The theoretical VAR(p) model used for this operation takes the following matrix form: nullnull=nullnull+nullnullnullnullnullnullnullnullnullnullnull+nullnullwher
26、e nullnull=nullnullnullnullnullnullnullnullnullnullnullnullnullnullnull is the vector of the analysis variables, nullnull= nullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnull is the matrix of the coe
27、fficients, nullnull= nullnullnullnullnullnullnullnullnullnullnull is the model constancy vector, nullnull= nullnullnullnullnullnullnullnullnullnullnullnullnull(0,) is white noise. In the vector Y, series transformations may be required in the presence of unit roots. The unit root test methodology is
28、 set out below. 2 Rec. ITU-T D.156 (2008)/Amd.2 (09/2012) b) Unit root test A feature of the structure of the telecommunication market in developing countries is the entry of new operators. This brings about a structural break in the economic series used to characterize the sector, particularly inve
29、stment, traffic and the number of subscribers. This situation is confirmed by the graphical representation of the series (Figure B.1). In the case of structural breaks, conventional unit root tests become unsuitable (Augmented Dickey-Fuller (ADF) (Perron, 1989). This Recommendation therefore applies
30、 the Zivot-Andrews (1992) test, which offers the advantage of incorporating an endogenous breakpoint (structural shift) and testing for the existence of a unit root in the series. Just like the ADF test, this test has three models according to whether the data reflect a break in constancy, in trend
31、or in both. It is the latter model which has been preferred, in other words we base ourselves on the hypothesis that the series may undergo a shift in both trend and constancy. Thus the basic model is written: nullnull=null+nullnull+nullnullnullnullnull+nullnullnullnullnullnull+null(null nullnull)nu
32、llnullnullnullnull+nullnullnullnullnullnullnullnullnullnullnull+nullnullwhere TB is the breakpoint date (1nullnullnull) and null the indicator function. The null hypothesis for this test is H0: = 1. When the calculated statistic t is smaller than the tabulated threshold, the null hypothesis is rejec
33、ted. B.2.2 Construction of the rule The known ratios between investment in countries of the South and that in OECD countries are considered. Using the data for these countries, we hypothesize a linear evolution (constant growth rate for the ratio). The equality horizon can thus be determined from th
34、e equation: null=lnnullnullnullnullnullnullln(1+)where is the growth rate assumed to be constant, and rTis the ratio of investment for the countries of the South and OECD. This expression enables us to determine, for fixed time frames, the growth rate of the ratio r. Finally, the ratio being equal t
35、o 1, the growth rate is obtained as follows: null=expnulllnnull1nullnullnullTnull1 On the basis of the different ratios obtained, the latter are compared with the actual ratios. The additional investment required to bridge the gap is then estimated. Let nullbe the expected ratio and nullnullthe pred
36、icted ratio (forecast). The additional investment is given by the equation: nullnull=nullnullnullnullnullnullnullnullnullnullThe premium is thus estimated as the ratio of additional investment to expected traffic, the underlying assumption being that the additional investment can be funded only by a
37、 price increase. null =nullnullnullnullnullnullnullnullnullRec. ITU-T D.156 (2008)/Amd.2 (09/2012) 3 B.3 Results The results are presented in two subsections: we demonstrate, on the one hand, the existence of network effects and, on the other, we attempt to determine the premium. B.3.1 Existence of
38、network effects The results of the unit root test are set out in Table B.1. They show that the investment and traffic series underwent a structural break in January 2007 (Figure B.2). The null hypothesis for the existence of a unit root cannot be accepted at the threshold of 1%. However, for the num
39、ber of network subscribers, the existence of a unit root is admitted at the 1%, 5% and 10% thresholds (the null hypothesis cannot be rejected). Table B.1 Unit root test Investment Traffic Subscribers ADF (without breakpoint) Trend No trend Trend No trend Trend No trend Level 2.171 1.787 3.523 2.808
40、2.300 9.334 First diff. 8.858 12.200 11.155 12.417 8.107 7.161 Zivot-Andrews t-min Date (break) t-min Date (break) t-min Date (break) 8.397* Jan. 07 6.809* Jan. 07 3.387 Jan. 06 * 1% significant level In the final analysis, the investment and traffic series are stationary, taking into account their
41、structural breaks, and the subscriber series (number of subscribers) is integrated order 1 (first-difference ADF test). Thus, in establishing the vector Y for the VAR model, appropriate transformations have been carried out. The vector Y thus comprises not initial variables but transformed variables
42、. Before estimating the VAR model, we should first find the optimal lag order (p) in the model postulated. This is done on the basis of the information criteria (AIC, SC, HQ), the likelihood ratio (LR) and the final prediction error (FPE). According to the results (Table B.4), we can estimate the mo
43、del with p = 15. The results of the Granger test (Table B.5) and the first estimates of the model show that we may consider the variable “subscriber growth rate“ as exogenous, thereby reducing our model to two endogenous variables. The VAR model estimates show that an increase in investment has a po
44、sitive effect on traffic (with a minimum time lag of two months). However, when the traffic in the network increases, this tends to reduce the volume of investment (negative investment growth before 14 months). At the 14th month, there is a positive investment reaction as a result of the traffic gen
45、erated at the outset (14 months previously). The sustained and positive growth rate in the number of subscribers has the effect of reducing the volume of traffic and investment. Actually, subscriber growth on the network should increase the number of calls. However, the dimensions of the network bei
46、ng limited, not all calls can be completed to their destination. This means that the reduction stemming from the subscriber growth is in fact a loss of traffic that could have been captured if the network had been big enough to absorb all the traffic. Shock analysis shows that a unit shock on traffi
47、c has the effect of reducing investment during the first two months after the shock, while boosting investment overall. The effect of the shock subsides around the 11th month following the shock. 4 Rec. ITU-T D.156 (2008)/Amd.2 (09/2012) In the case of an investment shock, traffic shows an upturn on
48、ly after a one-month time lag. The effect of the shock subsides six months after the shock. However, the effect does not cancel itself out, since it is still positive as from the 13th month. B.3.2 Determination of the externality premium Growth rates are calculated for time frames of five to 15 year
49、s (Table B.2). Table B.2 Growth rate by time frame Time frame 5 6 7 8 9 10 11 12 13 14 15 Growth rate 1.5590 1.1881 0.9565 0.7991 0.6854 0.5997 0.5328 0.4792 0.4353 0.3987 0.3678 Since the growth rates of the ratio are known, investment forecasts have to be provided for these two groups of countries for a 7 to 15-year time-frame. A time frame of five or six years is unrealistic, since this would require annual growth rates of 118% to 156%. The additional expected investment (support) to attain the desired growth rate
