1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 % TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%0(/.%G0G0.%47/2+G0G0!.$G0G0)3$./0%2!4)/. G0G0.5-“%2). G0G02/54).G0G0!.$G0G0-/“),%3%26)#%)3$.G0G0.%47/2+G0G0)$%.4)&)#!4)/.G0G0#/$%3)45G134G0G02ECOMMENDATIONG0G0% (Extract from the “LUEG0“OOK)NOTES1 ITU-T R
2、ecommendation E.167 was published in Fascicle II.2 of the Blue Book. This file is an extract from theBlue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright condition
3、s remain unchanged (see below).2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any f
4、orm or by any means, electronic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle II.2 - Rec. E.167 1Recommendation E.167Fascicle II.2 - Rec. E.167ISDN NETWORK IDENTIFICATION CODES1 GeneralThis Recommendation presents the interim structure for th
5、e ISDN Network Identification Code (INIC) that isused to identify an ISDN network in Closed User Group (CUGs) and in certain X.75 utilities. The interim INIC doesnot form any part of an E.164 number.The structure of a permanent INIC has not been agreed, and is for urgent further study.2 Usage2.1 Clo
6、sed user groupsThe format of the Interlock Code (IC) in Signalling System No. 7 is based on the format defined inRecommendation X.180 concerning closed user group utilities and used in Recommendation X.75, i.e., a 32 bit codedivided into two parts. Part A is 16 bits and is coded to identify a 4 digi
7、t number, and Part B is coded as a 16 bitequivalent of a decimal number.Part A will consist of an interim INIC or a Data Network Identification Code (DNIC) to identify theindividual ISDN (or PDN) that is responsible for administering the closed user group (CUG). Part A of the IC containsspace for a
8、string of 4 decimal digits. The interim INIC thus is a string of 4 digits beginning with a digit thatdistinguishes interim INICs from any DNIC.2.2 X.75 utilitiesThe interim INIC can be used to identify an ISDN in the TNIC (Transit Network Identification Code) andCNIC (Clearing Network Identification
9、 Code) CUG utilities of the X.75 protocol.3 Format of the interim ISDN network identification code3.1 DefinitionThe interim INIC is a string of 4 digits. Each different string of digits may be used to identify an individualISDN. The first digit I distinguishes the INIC from a DNIC. This digit is fol
10、lowed by the country code from theE.163/E.164 numbering plan which has a length of one, two or three digits (see Recommendation E.163). TheE.163/E.164 country code is followed by enough additional digits, X, to make the total length of the INIC 4 digits. Theformat is shown in Table 1/E.167.TABLE 1/E
11、167Format of the interim INICI is the initial digit, C is a digit of the country codeand X is an additional digitCountry code INIC FormatOne digit ICXXTwo digits ICCXThree digits ICCC2 Fascicle II.2 - Rec. E.1673.2 Digit IThe digit I may be 0 or 9. The use of the digits 8 and 1 as the digit I requi
12、res further study.3.3 Additional digitsEach additional digit is a digit in the range 0 to 9.3.4 Other formatsThe formats 00XX and 90XX could provide for 200 additional INICs not associated with specific countrycodes. These are for further study.3.5 AdministrationEach unique combination of digit I, c
13、ountry code, and additional digit(s) can identify a different ISDN, or partof an ISDN.The Administration to which the country code has been assigned is responsible for administering the digit I andthe additional digit(s).Within each country, it is suggested that the INICs beginning with the digit I
14、 0 be assigned first, followed byINICs beginning with the digit I = 9.3.6 Duration of the interim definitionThe interim INIC is for immediate use. Its use will continue until a permanent definition has been agreed to,and a period beyond that to allow a transition to the use of the permanent definit
15、ion.4 Further usageWhile other uses of the interim INIC are possible, proponents of such use are strongly urged to consider thattheir implementation should be easily adaptable to the permanent format of the INIC.5 Format of the permanent ISDN network identification codeThe definition of the permanent format of the INIC is for urgent further study.
