1、 STD*ITU-T RECMN Q=BZ*q-ENGL 1980 M 48b2591 Ob302b5 9bT INTERNATIONAL TELECOMMUNICATION UNION ITU=T Qm82.4 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU GENERAL RECOMMENDATIONS ON TELEPHONE SWITCHING AND SIGNALLING FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN STAGE 2 DESCRIPTION FOR CA
2、LL OFFERING SUPPLEMENTARY SERVICES - LINE HUNTING ITU-T Recommendation Q.82.4 (Extract from the Blue Book) STD-ITU-T RECMN Q-82.4-ENGL 1988 4Bb2591 Ob302bb BTb NOTES 1 ITU-T Recommendation Q.82 was published in Fascicle V1.l of the Blue Book. This file, which is an extract from the Blue Book. contai
3、ns only the part of the Recommendation still in force. While the presentation and layout of the text might be slightly different from the BIue Book version, the contents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below). 2 telecommunication admi
4、nistration and a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1988, 1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, incl
5、uding photocopying and microfilm, without permission in writing from the ITU. STD-ITU-T RECMN Q-829q-ENGL 1988 48b257L Ob302b7 732 Recommendation Q.82.4 STAGE 2 DESCRIPTION FOR CALL OFFERING SUPPLEMENTARY SERVICES - LINE “TING 4 Line hunting 4.1 Introduction 4.1.1 Definition distributed over a group
6、 of interfaces. addresses, rather than on interfaces is a possible extension of the service. Line hunting is a supplementary service which enables incoming calls to a specific ISDN number to be Note - Expansion of the line hunting service to cover the case of hunting on available ISDN numbers or 4.1
7、2 Description This description covers the form of line hunting which applies to interfaces within one node. It is an anticipated further extension to enable the group of interfaces available for selection to be distributed over more than one node. The selection of an interface within a node is perf
8、ormed on the basis of the hunting algorithm used. (Where hunting is extended over more than one node the network routing techniques used to extend the selection to the next node may be similar to that used for the call forwarding supplementary service, though applied by the Administration. The preci
9、se description of multi-node line hunting is for further study.) An access belonging to a line hunting group may also be addressed using an individual ISDN number. Facilities associated with the individual number are not affected by line hunting. 4.2 Definition of the functional model The additional
10、 functionality required for line hunting, over that of the basic service, is confmed to a single node, as seen in Figure 4-1lQ.82. FIGURE 4-1/Q.82 Rehtionrhip of line huntiag to baric service Fascicle VI.1 - Rec. Q.82.4 1 4.3 Information flow 4.3.1 Flow for single node hunting For the single node ca
11、se, the information flows are those defined for the basic call as shown in Figure 4- 2Q.82. No information flows arise as a result of the hunting action. (Continue as per basic call) Note I - Only those entities directly involved in liae hunting we 8hOWIL Note2 - The selected access may be to a CC o
12、r a CCA. FIGURE 4-WQ.82 Informition fim for Uno hunting 4.3.2 Flow for multi-node hunting This is for further study. 2 Fascicle VI.l - Rec. 4.82.4 4.4 SDL diagrams The SDL diagrams for the entity FE1 are shown in Figure 4-314.82 and Figure 4-4lQ.82. Line hunting FE1 BASIC SERVICE SELECTION SELECT AC
13、CESS - Note 2 NO ACCESS ACCESS SELECTED SELECTED EXTEND SEARCH Note 1 I ND ICATE CALL PROCEEDING UNSUCCESSFUL Note I - For hirther study. Nore 2 - This process is described within the basic service description. Nore 3 - This SDL is executed within the “Tenn. Screen. Process Attempt” process boxes at
14、 reference points 241, 241A in the basic call SDL FIGURE 4-3/Q.82 SDL1 for line huiiting Fascicle VI.1 - Rec. 4.82.4 3 SELECT ACCESS SELECT 1ST ACCESS INFORMATION CHANNEL (USABLE FOR THIS CALL) AVA I LAB L E ACCESSES CHECKED SELECT ACCESS 1 NEXT I UNIFORM SELECT ACCES TO MAINTAIN AN EQUAL DISTRIBUTI
15、ON OF CALLS 7- I SELECTION PROCESS Q NO ACCESS SELECTED ACCESS SELECTED FIGURE 444.82 SDU for Ilne bunting 4 Fascicle VI.l - Rec. Q.82.4 STD*ITU-T RECMN Q.82-4-ENGL 1988 48b2571 Ob30271 1b3 Functional entities Scenario 1) Basic rate access 2) Basic rate access 3) Primary rate access 4.5 Functional e
16、ntity actions CCA cc cc CClFE1 cc CCA TE TE LE TR LE TE TE LE TR NT2 TE LE TR LE NT2 TE - - 4.5.1 Single node hunting The FEAs attributed to entity FE1, the line hunting entity, indicated by (1) on the information flow diagram - determine hunting algorithm; - select free interface. are as follows: 4
17、5.2 Multi-node line hunting FEAs, in addition to the single node FEAS, which are required for hunting over more than one node are for further study. 4.6 Physical locations for functional entities The scenarios which apply to line hunting are shown in Table 4-UQ.82. TABLE 4-1/Q.82 Fascicle VI.1 - Rec. Q.82.4 5
