1、CCITT RECMN*M.Y030 92 YB62593 0579359 b44 - I N T E R NAT I O N AL TE LEC OM M U N I CAT I O N U N I O N CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE M.401 O (1 0/92) MAINTENANCE : COMMON CHANNEL SIGNALLING SYSTEMS INTER-ADMINISTRATION AGREEMENTS ON COMMON CHANNEL SIGNALLIN
2、G SYSTEM No.6 I Recommendation M.4010 CCITT RECMN*fl*4010 92 m 48b2591 0579160 3bb m FOREWORD The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating a
3、nd tariff questions and issuing Recommendations on them with 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 Recomm
4、endations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). Recommendation M.4010 was revised by Study Group IV and was approved under the Resolution No. 2 procedure on the 5th of October 1992. CCIT NOTE In this Reco
5、mmendation, the expression ?Administration? is used for conciseness 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 mech
6、anical, including photocopying and microfilm, without permission in writing from the ITU. CCITT RECMN*M-4010 92 m 4862591 0579LbL 2T2 = Recommendation M.4010 INTER-ADMINISTRATION AGREEMENTS ON COMMON CHANNEL SIGNALLING SYSTEM No. 6 (Published in 1984 as M.750; revised and renumbered in 1992) Abstrac
7、t Describes agreements necessary between Administrations which intend to exchange signalling information over common channel Signalling System No. 6. Examples are: - - - options; - etc. the number and type of links; signalling method (en-bloc or overlap); The outline of a test programme is provided
8、with information on where further details may be found. Keywords - agreement; - common channel; - line-up; - signalling No. 6. 1 Introduction The bringing into service of new telephone circuits and signalling systems requires that a number of agreements be made in advance by the Administrations invo
9、lved. Examples of such agreements are: - - - circuit designations; - For common channel signalling systems, a number of agreements are needed in addition to those required for routing of circuits (cable, satellite, etc.); mode of operation (incoming, outgoing, both-way); order of selection of both-w
10、ay circuits. channel-associated signalling systems (e.g. R2). This Recommendation explains the principal inter- Administration agreements which must be made in advance of opening a Signalling System No. 6 service and is provided as guidance to those Administrations intending to operate such a servic
11、e. Many of the aspects covered by this Recommendation relate to matters contained in the specification of Signalling System No. 6, as appearing in the Q-Series Recommendations i. Where appropriate, cross references to such Recommendations are given. 2 Common channel Signalling System No. 6 (SS No. 6
12、) The introduction to the specification of SS No. 6 and Recommendation Q.251 2 provide general and functional descriptions of the signalling system. Recommendation M.760 17 contains a basic diagram of SS No. 6 and a general description of the (signalling) transfer link. Recommendation M.4010 (10/92)
13、 1 CCITT RECMN*M*40LO 92 48b2593 0579362 339 3 Aspects of SS No. 6 requiring inter-Administration agreement 3.1 Signalling links und signalling security arrangements Signals for a given group of speech circuits between two exchanges may be “associated” (routed on a signalling link between the two ex
14、changes), “non-associated (routed on two or more signalling links in tandem, involving one or more signal-transfer-points) or a mixture of both (see 4 1.3.1 of Recommendation Q.253 3). The possible modes of operation range from simple arrangements of one signalling link and associated mode of signal
15、ling, to more complex arrangements, for example, the fully dissociated mode where signals are wansferred via any available path in a signalling “network”. Before entering detailed discussions on the type of signalling security arrangements required, it is desirable that the terminal Administrations
16、exchange information on the type and manufacturer of their international exchanges and the options available within their existing software systems. This information will enable each Administration to have an overall view of available signalling security arrangements; it will avoid misunderstandings
17、 and thus enable rapid progress in establishing detailed arrangements. Subsequently, agreement on the following matters will be required: i) The number of signalling links and reserves to be provided (Recommendations Q.292 4 and Q.293 5). In general, a choice will be made between: - regular link plu
18、s synchronized reserve(s); - regular link plus non-synchronized reserve(s). Such non-synchronized reserves may be reserve transfer links or nominated speech circuit reserves. Where the latter is chosen, the measures to be taken to ensure that there is a high probability of one of the chosen speech c
19、ircuits being free (at both ends) when required should be discussed between Administrations (see 0 8.4.3 a) of Recommendation Q.292 4); - load-sharing. The order of selection (ranking order) of regularheserve signalling links, reserve transfer links and nominated speech circuit reserves, as provided
20、. Where non-synchronized reserves are concerned, the time each terminal exchange will attempt to regain synchronization (5 or 7.5 seconds) must be agreed between Administrations (see 4 8.6.3.2 of Recommendation Q.293 5). iii) The order of selection between alternative signalling routes (where more t
21、han one has been provided). iv) The need to specify an “automatic load transfer” procedure (see 4 8.6.3.2 of Recommen- ii) dation Q.293 5). Which exchange will act as “emergency restart control exchange” (see 9 8.7 c) of Recommen- dation Q.293 5). v) 3.2 Signalling link routing and line-up aspects A
22、dministrations must reach agreement on the physical routing and line-up requirements of the signalling links and reserves. Among the aspects which are important are: i) ii) diversity of routing for alternative signalling links and reserves, as required for security purposes; the propagation delay of
23、 signalling links and reserves. This should be as low as possible and should not be significantly greater than that of any speech circuit with which it is normally associated. By this means the possibility of the called party being distorted or “clipped” is reduced (see Recommen- dation Q.272 fi); i
24、ii) the existence or absence of restoration plans to restore transmission facilities over which signalling links and reserves are routed; iv) the transmission characteristics and limits to be used for the transfer links (see Recommen- dation M.4030 is). 2 Recomrnenda tion M.4010 (10B2) 3.3 Method of
25、 signalling Signalling System No. 6 provides for two basic methods of sending signalling information namely, “en-bloc“ or “overlap“ (see Recommendations Q.262 7 and Q.265 8). The method to be used for each direction of traffic should be discussed and agreed between Administrations. 3.4 Use of option
26、al facilities 3.4.1 Nenuork maintenance signals Network maintenance signals are specified as an optional facility in the specification of SS No. 6 (see 0 9.5 of Recommendation Q.295 9). Where both terminal exchanges are equipped with these facilities, the involved Administrations may wish to reach a
27、greement on their use, for example to facilitate recovery from major exchange or signalling system disturbances. In making such agreements, it must be ensured that any “signal-transfer- point“ involved between the two terminal exchanges is able to transfer the necessary network maintenance signals.
28、3.4.2 Automatic repeat attempt The specification for SS No. 6 requires that an automatic repeat attempt be made in a number of specified call failure situations. However, the potential exists to use an automatic repeat attempt in circumstances other than those specified. Administrations may wish to
29、discuss the advantages (if any) of additional application of the automatic repeat attempt facility (see Recommendation Q.264 lo) and the implications, for example, on the load on the signalling data link, of such additional use. 3.5 Label assignment By agreement between Administrations, each SS No.
30、6 speech circuit must be assigned a “label“, comprising a “band number“ and a “circuit number“ (see Recommendation Q.257 i i). Any relationship required between the band numbering scheme and the physical routing of the speech circuits (via cable, via satellite, etc.) must also be agreed between Admi
31、nistrations. It may be noted that there need be no relationship between the circuit number part of the label and the circuit designation (which would be in accordance with Recommendation M.1400 14). For convenience, however, it is desirable where possible to retain an orderly and consistent equivale
32、nce between circuit number and circuit designation. 3.6 Double seizure of both-way circuits Signalling System No. 6 incorporates a procedure for dealing with a situation where a both-way circuit has been simultaneously seized at both ends (see Recommendation Q.263 12). This procedure requires that c
33、ontrol and non-control exchanges be appointed for each (both-way) circuit. It may be noted that there need be no relationship between control and non-control exchanges for double seizure and. the circuit control and sub-control stations as defined in Recommendations M.723 15 and M.724 i61 (unless so
34、 desired by the involved Administrations). For convenience, however, it is desirable where possible that Administrations exercise both dual seizure control and maintenance control over the same circuits. 3.7 Signal-transfer-point working Among the aspects upon which Administrations may need to reach
35、 agreement are: i) label translation and the need for control of label assignment (see 0 1.3.3.2 of Recommendation 4.253 31); ii) financial accounting. Where the non-associated mode of signalling has been adopted, either normally or as a signalling security arrangement, signalling information will b
36、e relayed via one or more signal- transfer-points and would typically involve one or more transit Administrations. Arrangements for any necessary financial accounting may need to be discussed and agreed between involved Administrations. Recommendation M.4010 (10/92) 3 3.8 Test programme Details of a
37、 test programme to be carried out prior to the start of the SS No. 6 service should be agreed between Administrations. This agreement and the resulting test schedule should take account of the relative experience of the participating Administrations. The following aspects should be covered in such a
38、 programme: i) ii) signalling security arrangements; functional and synchronization aspects of the signalling links and reserves; iii) call processing. Tests should cover normal, abnormal, transit and signal-transfer-point signalling sequences; iv) system failure response. Both signalling system and
39、 exchange failures should be covered; v) tests on individual speech circuits, e.g. using ATME No. 2; vi) limited period, live traffic tests. The programme suggested above is given as an example of the broad areas to be covered, and is not intended to be a complete test programme. In considering item
40、s to be included in a test programme, attention is drawn to the extensive and detailed publication, CCIT Signalling System No. 6 Test Schedule 13. 3.9 Maintenance and maintenance organization Inter-Administration agreements necessary for the maintenance of SS No. 6 are the subject of other Recommend
41、ations in the M-Series. Reference should be made to Recommendations M.760 17, M.4030 18, M.762 19 andM.1510 20. 4 Timing of inter-Administration agreements Due to the differing practices and procedures of Administrations, no specific timetable for the inter- Administration agreements necessary on SS
42、 No. 6 can be offered. However, experience indicates that initiai discussions between involved Administrations concerning a new SS No. 6 service should preferably commence about two years prior to the required “ready for service“ date. References CCITT Recommendations Q.251 to Q.300 Specifications o
43、f Signalling System No. 6. CCIIT Recommendation Q.251 General. CCITT Recommendation Q.253 Association between signalling and speech networks. CCITT Recommendation Q.292 Reserve facilities provided. CCIT Recommendation Q.293 Intervals at which security measures are to be invoked. CCIT Recommendation
44、Q.272 Requirements for the signalling data link. CCITT Recommendation Q.262 Analysis of digital information for routing. CCIT Recommendation Q.265 Speed of switching and signal transfer in international exchanges. CCIT Recommendation Q.295 Testing and maintenance - Overall tests of Signalling System
45、 No. 6. CCIT Recommendation Q.264 Potential for automatic repeat attempt and re-routing. Recommendation M.4010 (10192) CCITT RECMN*M.4030 32 E 4862533 05793b5 948 CCIT Recommendation Q.257 General. CCITT Recommendation Q.263 Double seizing with both-way operation. CCIIT Publication CCIT Signalling S
46、ystem No. 6 Test Schedule, ITU, Geneva, 1982. CCITT Recommendation M. 1400 Designations for international network. CCITT Recommendation M.723 Circuit control station. CCIT Recommendation M.724 Circuit sub-control station. CCITT Recommendation M.760 Transfer link for common channel Signalling System
47、No. 6. CCITT Recommendation M.4030 Transmission characteristics for setting-up and lining-up a transfer link for common channel Signalling System No. 6 (analogue version). CCIT Recommendation M.762 Maintenance of common channel Signalling System No. 6. CCIT Recommendation M. 1510 Exchange of contact point information for the maintenance of international services and the international networks. Recommendation M.4010 (10/92) 5 CCITT RECMN*N-4030 72 = 4862573 0577366 884 Printed in Switzerland Geneva, 1993
