1、CCITT RECMN*M=3620 92 D 4862591 0579344 113 D INTERNATIONAL TELECOMMUNICATION UNION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE MAINTENANCE: ISDN M.3620 (1 0/92) PRINCIPLES FOR THE USE OF ISDN TEST CALLS, SYSTEMS AND RESPONDERS i Recommendation M.3620 CCITT RECMN*M*3620 92
2、 m 48b259L 0579345 05T m FOREWORD The CCIT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with
3、a view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies
4、is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). Recommendation M.3620 was prepared by Study Group IV and was approved under the Resolution No. 2 procedure on the 5th of October 1992. CCITT NOE In this Recommendation, the expression “Administration” is used for conc
5、iseness to indicate both a telecommunication administration and a recognized private operating agency. O ITU 1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permis
6、sion in writing from the ITU. CCITT RECMN*M*3b20 92 48b2591 05791116 T9b Recommendation M.3620 PRINCIPLES FOR THE USE OF ISDN TEST CALLS, SYSTEMS AND RESPONDERS (1992) Abstract This Recommendation provides the general principles associated with ISDN test calls originating from a test system and term
7、inated by a test call responder. It lays down the requirements associated with test calls and lists the facilities that should be provided by a test call responder. Keywords - bearer type; - ISDN network; - ISDNnodes; - ISDN test calls; - teleservice; - test access; - test responders; - test systems
8、. 1 Overview 1.1 General principles for ISDN test calls It is recognized that in the ISDN environment, use of controlled maintenance techniques outlined in Recommendation M.20 11 will indicate areas where problems exist but not necessarily enable maintenance personnel to localize faults to specific
9、equipment. To overcome this problem, the proposed ISDN test call facility should - enable rapid localization and diagnosis of faults without disruption to the ISDN network - avoid or minimise testing across sections of the ISDN network not directly associated with a failure condition; - verify repai
10、red equipmenthestored connections before return to service; - - aid commissioning of new services; enable testing of new network interworking. 1.2 Attributes of ISDN test calls An ISDN test call may be steered and may generate diagnostic information. Where a failure would occur with live traffic, th
11、is should be unambiguously indicated (by actual failure or a failure message). The technician seeking to generate an ISDN test call should be able to relate types of ISDN call Set-ups on which users may have experienced difficulties, to types of test calls which are available to simulate them. Recom
12、mendation M.3620 (10/92) 1 CCITT RECflN*fl.3620 92 m 4462591 0579347 722 m 2 Test calls 2.1 Test system functions 2.1.1 ISDN test call capabilities recognize these as different types of available test calls. The following would be available: Complex combinations of services and parameters should be
13、transparent to the test technician who would - - any particular device or routing may be selected in combination with any available ISDN service; any available bearer type or teleservice may be selected in combination with some appropriate supplementary service; any invalid test call type should be
14、abandoned by the test facility and indicated to the test technician; any ISDN call which would fail in service (because of unsupported services, for instance) should either fail as a test call or clearly indicate a failure condition; duplicate all types of valid ISDN call Set-ups; - - - - route on d
15、estination; - route selectively on bearer/equipment? 2.1.2 Identify failure situations The ISDN test system should display clear information on an attempted ISDN call Set-up. This should include - - diagnostic information; - success or failure of the ISDN test call; and optionally; display of call c
16、ontrol messages. 2.1.3 Verification of routing The correct routing of an International ISDN test call should “2 positively confirmed to the originating - , a coded message returned by the ISDN test termination giving the type and location of the termination or in its simplest form; - a recorded anno
17、uncement. maintenance personnel. This confirmation could take the form of 2. i .4 Network pedormance test 2.1.4.1 Transmission tests An ISDN test facility should provide access to the bearer(s) established in the call set-up for the following applications: - - - test of continuity and integrity to C
18、CIT standards for digital circuits; trial interconnection for ISDN devices; telephony contact between test engineers. 2.1.4.2 Tests for other parameters For further study. 2.1.5 Single end testing Recommendation O. 1 1. An ISDN test termination shall enable single end testing by means of digital loo
19、pback as defined in The test termination referred to here would be accessed as a dial-up facility. It is recognized that this facility will only be available when an ISDN test station is part of the fabric of a switching unit. 2 Recommendation M.3620 (10/92) CCITT RECMN*M=3620 92 4862591 0579148 869
20、 = 2.2 ISDN responder equipment The ISDN test termination could be associated with equipment capable of - - carrying out a pre-determined sequence of interactive tests; returning parameters and other service information to the originating test technician. These uses have implications for digital ATM
21、E and testing protocols under TMN, and are considered to be beyond the scope of this Recommendation. 2.3 ISDN responder facilities 2.3.1 Valid test calls The responder should respond automatically to any available bearer type or teleservice. This may be implemented in combination with some supplemen
22、tary services. 2.3.2 Test access A test access responder should have the capability to terminate calls from each of the available bearer capabilities (e.g. 64 kbits, 3.1 kHz or speech). 2.3.3 Return messages In the event of a test call being successfully routed to a responder, the responder should r
23、eturn an intelligible message to the originating node. The message should include - the responders identity; - - the bearer capability (e.g. 64 kbit/s, 3.1 kHz or speech); the call teleservice (e.g. G4 Fax). The message should be returned by one of the following means: - in signalling user informati
24、on provided by ISDN signalling; - data returned over the bearer (i.e. in-band); - voice message over the bearer. 2.3.4 Test system to test responder interactions It is anticipated that on seizure, the following sequence of events would take place: - the ISDN circuit termination would be seized; - -
25、- - the return message would be returned using one of the methods discussed in the digital loopback would be established on the termination if required; the digital loopback would be disconnected if required; the bearer would be held available for interworking by the local test station with the dist
26、ant end if required. 3.3.3; 3 Destination of ISDN test calls The ISDN test call system should have the capability to generate test calls to any ISDN signalling system or variant supported by the switching centre(s) with which it is associated. Recommendation M.3620 (10/92) 3 3.1 Ifi CCITT RECMN*N*36
27、20 72 4862593 0579349 7T5 yrnational ISDN nodes Test call facilities will be located at, and will operate between, major nodes on the international ISDN. Initially, it is proposed that these should be located on the national side of international gateways or at locations which are functionally equiv
28、alent. 3.2 Other ISDN nodes It is recognized that the ISDN test call facilities defined in this Recommendation have possible implications throughout the ISDN network. The location of ISDN test call facilities in National networks is subject to - agreement between originating and receiving administra
29、tions; - agreement between originating and transiting administrations; - conformance to the general principles of testing “maintenance entities” as defined in Recommendation M.20 i. 3.3 Conjdence testing The routing of ISDN test calls to ISDN test terminations associated with the same switch or switching complex shall be possible for confidence and local testing purposes. Reference il CCITT Recommendation M.20 Maintenance philosophy for telecommunications networks. 4 Recommendation M.3620 (10/92) CCITT RECMN*M3620 92 H 4862593 0579350 417 Printed in Switzerland Geneva, 1993
