ITU-T Q 107 BIS-1993 Analysis of Forward Address Information for Routing - General Recommendations on Telephone Switching and Signalling - Clauses Applicable to ITU-T Standard Syst.pdf

1、ITU-T RECMN*Q.L07 BIS 93 = 48b2591 0588988 303 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.107 bis (03193) GENERAL RECOMMENDATIONS ON TELEPHONE SWITCHING AND SIGNALLING CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS ANALYSIS OF FORWARD ADDRESS INFORMAT

2、ION FOR ROUTING ITU-T Recommendation Q.107 bis (Previously “CCITT Recommendation”) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesFOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the Internation

3、al Telecom- munication Union. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every fou

4、r years, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. ITU-T Recommendation Q.107 bis was revised by the ITU-T Study Group XI (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of

5、 a reform process within the International Telecommunication Union (ITU), the CCIT” ceased to exist as of 28 February 1993. In its place, the ITU Telecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replac

6、ed by the Radiocommunication Sector. In order not to delay publication of this Recommendation, no change has been made in the text to references containing the acronyms “CCITT, CCIR or IFRB” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendati

7、on will contain the proper terminology related to the new ITU structure. 2 telecommunication administration and a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1994 I All rights reserved. No part of this publicat

8、ion may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesCONTENTS 1 Genera

9、l . 2 Digit analysis at the outgoing international exchange 3 Digit analysis at the international transit exchange 4 Examples of the digit analysis in an international transit exchange . 4.1 Example 1 . 4.2 Example 2 . 5 Example of digit analysis for incoming terminal traffic 6 Cross-border traftic

10、between adjacent countnes Reference . Recommendation Q.107 bis (03/93) Page 1 1 2 3 4 4 4 5 5 i COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesRecommendation Q.107 bis ANALYSIS OF FORWARD ADDRESS INFORMATION FOR ROUTING (Geneva, 1980:

11、moded at Melbourne, 1980 and at Helsinki, 1993) 1 General This Recommendation covers the analysis of forward address information for the routing of circuits using Signalling Systems No. 4, No. 5, No. 6, No. 7 and R2. For Signalling System RI, Recommendation Q.324 i indicates that in the application

12、of Signalling System R1 to intra- regional networks, the routing plan of that network shall apply. The routing plan is such that analysis is limited to a maximum of six digits. Signalling Systems No. 4, No. 5, No. 6, No. 7 and R2 as specified are suitable for international application (see also Reco

13、mmendation 4.7) and Recommendations 4.12 and 4.13 on routing are applicable. Similarly, for international traffic the combinations of digits to be sent must be in accordance with Recommendations Q.10, Q.11 bis and Q.101 to Q. 107. Based on the forward address information received (see Recommendation

14、 Q.107), routing is performed at the outgoing intemational exchange and at the following (transit) exchanges. For this purpose, an analysis of some of the information received is required. Recommendation 4.107 specifies the standard sequences of forward address information for each of the signalling

15、 systems mentioned above. 2 Digit analysis at the outgoing international exchange The ISDN numbering plan is based on an extension of the existing numbering plans applicable to national and international public telephone networks. In fact, ISDN services may be provided under the existing numbering p

16、lan for the international telephone service. However, some Administrations may choose to allow for full E.164 numbers (maximun 15 digits). Therefore, the associated change which motivates an increase in the maximum number of digits which must be analysed in the outgoing international exchange to det

17、ermine routing should be fully supported. More specifically, according to Recommendation E.164, this maximum should be equal to 6 digits, the language digit (L) or the discriminating digit ) not being included. Some examples of the information required to determine routing at an international exchan

18、ge are given in the following: where Il, IL, 13 are the digits of the country code Z Ni, . . . N, is the characteristic digit, Le. discriminating digit (D) or language digit (L), and are the digits of the national (significant) number. In cases where the country code is shared by different countries

19、, up to 7 digits may have to be analysed for routing and accounting purposes. In the implementation of new intemational exchanges, this should be taken into account. In general, the whole amount of forward address information relating to international calls is stored at the outgoing international ex

20、change. Recommendation Q.107 bis (03/93) 1 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesSome examples of the information required to determine the routing at an international exchange are given in the following: where Ii,I2,13 Z Ni,

21、. . . N, are the digits of the country code is the characteristic digit, i.e. discriminating digit (D) or language digit (L), and are the digits of the national (significant) number. The maximum number of digits which have to be analysed in the outgoing international exchange to determine the routin

22、g is 5, the language digit (L) or the discriminating digit (D) not being included. In cases where the country code is shared by different countries, up to 7 digits may have to be analysed for routing and accounting purposes. In the implementation of new international exchanges, this should be taken

23、into account. In semi-automatic working, in the case where the language digit is not sent by the operator, and in automatic working, it is necessary to determine (in the outgoing international exchange) the position where the language or discriminating digit must be inserted automatically (for chann

24、el associated signalling systems immediately after the country code). This position is determined by an analysis of the first or the first two digits of the country code. A three-digit country code can also be detected by an analysis of the first two digits. In the case of countries with more than o

25、ne incoming international exchange where semi-automatic calls to code 11 or code 12 operators require a digit analysis beyond the country code for routing in the outgoing international exchange, N, may be used as the extra digit designating the incoming international exchange. For direct relations b

26、etween the outgoing exchange and the incoming exchanges, sending of the digit N, to the incoming international exchanges is not required2) . 3 Signalling equipment for transit exchanges must be designed for the transfer of all information necessary for setting up calls including access to operators

27、positions. In an international transit exchange, analysis of some of the digits is required to determine the routing to the desired international incoming exchange or to another international transit exchange. The maximum number of digits which has to be analysed at the international transit exchang

28、e to determine the routing is 6, the language (L) or the discriminating digit (D) not being included (see also 2). In cases where the country code is shared by different countries, up to 7 digits may have to be analysed for routing and accounting purposes. In the implementation of new international

29、exchanges, this should be taken into account. The transit exchange decides how many of the received digits it needs for this analysis. In an international transit exchange, an analysis, effective on the first or the first two digits of the country code, determines the number of digits in the country

30、 code. For channel associated signalling systems, the position of the language or the discriminating digit is therefore determined which, in the sequence of forward address information, follows immediately the country code. Digit analysis at the international transit exchange i) In the cases of comm

31、on channel Signalling Systems No. 6 and No. 7, the information content of the D or L digit will be conveyed by the cailing-party s-category indicator. 2, It is recognized that the existing design of some equipment may not permit the reception of the extra digit NI. In this situation, agreement will

32、be required between the relevant countries concerned that the extra digit NI would not be sent to a particular incoming intemational exchange. 2 Recommendation Q.107 bis (03/93) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesITU-T RECM

33、N*d-107 BIS 93 4862591 0588993 O70 Since in the case of common channel Signalling Systems No. 6 and No. 7 the initial address message contains all digits required for routing the call, selection of the outgoing circuit can start as soon as this message has been received. In addition to the digit inf

34、ormation, other routing information is contained in the initial address message, e.g. country code or nature-of-address indicator, nature-of-circuit indicator, caiiing-partys-category indicator, and echo-suppressor indicator, some or all of which must be analysed as described in the detailed specifi

35、cations. Nomially, it wiil not be necessary for a transit exchange using Signalling System No. 6 or No. 7 to analyse digits in more than the initial address message. Subsequent address messages can be forwarded to the next international exchange without analysis as soon as the outgoing circuit is de

36、termined. In the case of Signalling System No. 6, however, a subsequent address message (SAM) must always be analysed for sequence reasonableness before being forwarded to the next international exchange. In the case of incoming Signalling System No. 4, the transit exchange must ensure that it does

37、not request signai code 15 in order to avoid premature release of the outgoing register, e.g. by evaluating the signal code 11 or code 12. 4 Examples of the digit analysis in an international transit exchange Possible cases for digit analysis by an international transit exchange are shown in the fol

38、lowing examples (the letters given to the international exchanges correspond to Figure 1 and the letters given to the digits correspond to the examples given in clause 2 above). It should be noted that in some cases analysis of fewer digits than those indicated in the foliowing examples may be suffi

39、cient. :s 7 ! O Tl158750-94IdOl M R FIGURE l/Q. 107 bis Examples of the digit analysis in an international transit exchange C Recommendation Q.107 bis (03/93) 3 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesITU-T RECflNUQ.107 BIS 93 W

40、 486259L 058899Y TO7 W 4.1 Example1 In example 1, transit traffk via C in one country is routed to one of the two exchanges M or R in another country according to the first digit(s) of the national (significant) number. a) Automatic and semi-automatic calls with normal national numbers Example: 11 I

41、2 2 Ni N23) b) Semi-automatic calls to code 11 or code 12 operators in the case where only one incoming international exchange (M or R) is equipped to receive calls to operators positions Examples: 11 12 L Cl1 or 11 12 L 123) In the case of countries with more than one incoming international exchang

42、e where code 11 or code 12 traffk requires for routing in the transit exchange a digit analysis beyond the country code, N, may be used as the extra digit designating the incoming international exchange4) . Examples: I, I, L N,C, or I, 1, L N,C1,3) - - analysed analysed 4.2 Example2 In example 2, tr

43、ansit traffk via C in one country is routed to G or S in another country. Automatic MIC with the presence of discriminating digit (D) is routed to G or S according to the first digit of the national significant number, while all semi-automatic traffic with the presence of language digit (L) is route

44、d to S for assistance operator use regardless of digits following L. Examples: I, I, D or I, I, L3) analysed analysed - 5 Example of digit analysis for incoming terminal traffic Terminal traffic incoming to an international exchange C in a country and which is to be routed to code 11 or code 12 oper

45、ators in another international exchange A in the same country according to the extra digit N14). Examples: LN, C, Cl, or LN, C, XXClSs) Y * analysed analysed 3, In the cases of common channel Signalling Systems No. 6 and No. 7, the information content of the D or L digit will be conveyed by the call

46、ing-party s-category indicator. 4, It is recognized that the existing design of some equipment may not permit the reception of the extra digit Ni. In this situation, agreement will be required between the relevant countries concerned that the extra digit Ni would not be sent to a particular incoming

47、 international exchange. In the cases of common channel Signalling Systems No. 6 and No. 7, the information content of the D or L digit will be conveyed by the calling-partys-category indicator. Code 15 may be considered as equivalent to ST in call CCm signalling systems. 4 Recommendation Q.107 bis

48、(03/93) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services6 If for cross-border traffic between adjacent countries access to operators positions is not provided, it may be decided by bilateral agreement to exclude the transfer of the lang

49、uage or the discriminating digit. In this case, the first digit sent will be the first of the national (significant) number. In addition, one or more of the first digits of the national (significant) number may be omitted, depending on the muting requirements at the incoming exchange. For cross-border traffic between adjacent countries, the number of digits that must be analysed will be determined by bilateral agreement. This may involve more digits than for normal international traffk. Cross-border traffic between adjacent countries Reference i CCITT Recommendation Analys