1、ITU-T RECNN*M.4100 7b = 4862571 Ob17787 431 = INTERNATIONAL TELECOMMUN CATION UN ION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU M.41 O0 MAINTENANCE COMMON CHANNEL SIGNALLING SYSTEMS (05196) MAINTENANCE OF COMMON CHANNEL SIGNALLING SYSTEM No. 7 ITU-T Recommendation M.41 O0 (Previously “CCI
2、TT Recommendation”) ITU-T RECMN*M.4LOO 96 4862593 Ob17988 378 FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITIJ). The -T is responsible for studying technical, operating and tariff questions and issuing Recommen- dat
3、ions on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which. in their turn, produce Recommendations on these topics. Th
4、e approval of Recommendations by the Members of the -T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). ITU-T Recommendation M.4100 was revised by -T Study Group 4 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 12th of May 19
5、96. NOTE In this Recommendation, the expression ?Administration? is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1996 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, elect
6、ronic or mechanical, including photocopying and microfilm, without permission in writing from the IT. ITU-T RECMN*M*4LOD 9b 4862.591 Ob37989 204 = CONTENTS General . Appointment of administrative control and sub-control Functions and responsibilities of the administrative control Operations under Si
7、gnal Transfer Point (STP) configurations . Implementing a new signalling system or a change to an existing system . Functions and responsibilities of the administrative sub-control . Monitoring requirements for maintenance purposes 6.2 Monitoring point requirements . 3.1 3.2 3.3 3.4 Day-to-day maint
8、enance of signalling systems History and long-term analysis . Contact point information 6.1 The software monitor 6.3 Requirements of test equipment used for monitoring purposes References . Page 1 1 1 2 2 3 3 6 6 6 7 7 7 8 Recommendation M.4100 (05/96) i ITU-T RECMN*M.4LOO 96 D 4862593 Ob37990 T2b A
9、BSTRACT This Recommendation considers the general administration of Common Channel Signalling System No, 7. It defines the administrative control and sub-control, their respective functions and responsibilities, contact point information and monitoring requirements for maintenance purposes. KEYWORDS
10、 Administrations, Agreements, Assignment, CIC code, Common Channel Signalling System No. 7, Continuity check, Label, Links, Linkset, Maintenance, Mode, Routing, Signalling-transfer-point. ii Recommendation M.4100 (05/96) ITU-T RECMN*M-4100 96 4862593 Ob37973 962 Recommendation M.4100 MAINTENANCE OF
11、COMMON CHANNEL SIGNALLING SYSTEM No. 7 (Melbourne, 1988; revised in 1993, 1996) 1 General 1.1 It is essential that a common channel signalling system perform with very high reliability over the long term. It is also desirable that maintenance staff perform at the highest practical efficiency. In ord
12、er to achieve both of these objectives with regard to common channel signalling systems, maintenance responsibilities and actions must be clearly defined and controlled. Such objectives make it necessary, in some cases, to place limitations on the freedom of involved maintenance units in performing
13、independent maintenance actions. 1.2 This Recommendation considers the signalling system as an integrated system. It is not intended to replace or supersede any Recommendation or procedure (national network or otherwise) which might apply to specific components or subsystems, for example a signallin
14、g terminal or the signalling data link; rather, it proposes criteria regarding when and how such actions are to be initiated. Moreover, the general administration of the systems is considered and not the detailed interworking of its various equipments. 1.3 Various maintenance organizational units ma
15、y have functional responsibility for individual subsystems which comprise a common channel signalling system (for example signalling terminals, processors, etc.). As the activities of any of these units will have an effect on the overall operation of the Signalling system, and because in some cases
16、it may not be possible to independently determine a need for maintenance attention, one point should be designated as an overall signalling system control. This point is entitled signalling system administrative control. The corresponding point at the distant terminal is known as the signalling syst
17、em administrative sub-control. 2 Appointment of administrative control and sub-control 2.1 The appointment of administrative control and sub-control will be made by agreement between the two Administrations (e.g. Administration No. 1 and Administration No. 2) involved. These two points must be assig
18、ned for each signalling system which is placed in operation. It is suggested that the most appropriate point to act as administrative control or sub-control is the maintenance unit having responsibility for the signalling terminal and processor. However, this matter is left to the discretion of the
19、Administrations Concerned. 2.2 In the case of multiple signalling systems between the same two points, it may be appropriate to divide control and sub-control assignments, therefore sharing the burden of control responsibility. This is a subject for agreement between the Administrations concerned; h
20、owever, this assignment and that of the control station for the transfer link should be to the same Administration. 3 Functions and responsibilities of the administrative control These responsibilities fall into four main areas: i) day-to-day maintenance of working systems; ii) history and long-term
21、 analysis; iU) operation under Signal Transfer Point (STP) configurations; iv) implementing a new signalling system or a change to an existing system. Recommendation M.4100 (05/96) 1 ITU-T RECMN*M=4LOO 96 4862593 ObL7992 8T9 3.1 Day-to-day maintenance of signalling systems 3.1.1 Except as noted in 3
22、.1.2, maintenance activity on any part of a common channel signalling system must only be undertaken with the agreement and knowledge of the administrative control. Such activities might relate to routine maintenance measurement of the signalling link, services affecting reconfigurations of transmis
23、sion systems over which signalling links are routed (i.e. planned outages), etc. Routine maintenance activities It is recommended that all routine maintenance and scheduled work activities be performed during hours of minimum traftc so that any inadvertent failure impacts the least number of custome
24、rs. At a minimum, high risk, potentially service affecting maintenance and growth procedures should be scheduled during weekend and off-hour. The overall methods, procedures and scheduling of these work activities should be reviewed by a sub-control maintenance organization. The activities that may
25、affect other network service providers must be coordinated, which includes both intra- and inter-Administration networks. Non-scheduled work activities - if customer service is being impacted, the minimum work activity will occur to restore the system to a stable performance state. Complete system r
26、ecovery activity will be scheduled for the next minimum traffk period. 3.1.2 In the event of total failure of a signalling system due to a malfunction of one of its parts, immediate steps should be taken to remedy the fault condition. As soon as possible, the administrative control should be informe
27、d so that the event can be correlated with other reported events or known signalling failure. In this scenario, when a total CCSS No. 7 failure is experienced, some means of communication between personnel in interconnecting Administration networks, may be required. The Administration should determi
28、ne what emergency communications are already available andor what alternative methods, if any, will be provided. 3.1.3 Faults which are observable only at a signalling system terminal, for example intermittent failures resulting from an apparently high data bit error rate, must be analysed by the ad
29、ministrative control (and sub-control, depending on the direction of the indicated fault) in order to determine where maintenance attention is required. Such dynamic analysis might involve terminal diagnostic tests, error performance tests with the distant terminal, etc. The result of this dynamic a
30、nalysis and tests will be corrective action, taken either by the administrative control, if under its jurisdiction, or by the sub-control, if under its jurisdiction, or the referral by the administrative control to the indicated part of the maintenance organization, for example the control station f
31、or the transfer link. 3.2 History and long-term analysis 3.2.1 signalling system for which it is responsible. The administrative control should maintain a record of all recognized or reported faults pertaining to each This information includes (but is not limited to) the following: i) date and time
32、a fault was reported or actually occurred; ii) the nature of the reported fault; iii) the reported location; iv) the location of the fault, when found; v) the actual fault condition found and the corrective action taken. This information should become a part of the history record maintained by the a
33、dministrative control. 2 Recommendation M.4100 (0996) ITU-T RECMN*M-4100 96 4862591 0637793 735 3.2.2 History records will enable long-term analysis to identify repeated faults of a signalling system. These records provide an ability to identify and correct potential problems before they become seri
34、ous enough to cause a fault. Such efforts should improve the long-term operation of a signalling system and therefore afford more economical maintenance. It is suggested that historical records should be retained for at least 12 months. From the provision of a new signalling system, the history reco
35、rd should be initiated and continue until 12 months have passed. After analysis, each succeeding month will permit the discaring of records accrued during that same month of the previous year. Therefore, an administrative control can examine 13 months of (possible) events, which should be adequate t
36、o identify persistent faulty conditions. 3.3 Operations under Signai Transfer Point (STP) configurations 3.3.1 With two or more signalling systems in tandem used to convey signalling information between two international centres, signal transfer point operation presents possible maintenance complica
37、tions. Events which occur in one system can affect the functioning between centres which have no control or sub-control responsibility for the faulty signalling system. If an administrative control determines that a fault has occurred in its signalling system which is part of an STP configuration, i
38、t must apprise the administrative control of the signalling system not directly involved, that a fault exists that affects (or will affect) signalling processes. The advice should also include an estimate of the time necessary to correct the condition and, when appropriate, the time of correction an
39、d the condition actually corrected, 3.3.2 When a condition affecting signalling via an STP warrants coordinated testing in order to determine the faulty part of either signalling system, the administrative control first involved in the fault report should coordinate testing efforts. Once the fault i
40、s localized, referrals can be made via normal procedures to achieve maintenance action. The following types of information should be exchanged at the time of the trouble referral: 0 circuit identification number for circuit specific troubles; 0 date and time of referral; o nature of the trouble and
41、any other information that may be of assistance in resolving the trouble; o trouble ticket number(s) or equivalent and the name or initial of the person accepting the trouble. When the fault is corrected, the administrative control for each of the signalling systems should be advised that the troubl
42、e has been cleared, the nature of the trouble found and the action taken. The administrative control which was first involved should confirm proper signalling via the S“. 3.4 Implementing a new signailing system or a change to an existing system Conversion from in-band signalling to CCSS No. 7 canno
43、t be accomplished without a thoroughly planned process. Two interconnecting Administrations implementation team should meet to discuss and identifj all of the steps necessary for a successful trunk conversion. Each administration should establish a Cutover Committee consisting of permanent members f
44、rom the Ordering, Provisioning, Engineering, Operations, CCSS No. 7 Administration Control Centre and Billing disciplines. The responsibility of the committee is to ensure a smooth conversion through scheduling and addressing, taking into consideration the concerns listed below. 3.4.1 Administration
45、s. They are not all inclusive. The following guidelines are offered as a starting point for discussion between two interconnecting - TIME OF THE CONVERSION - On what day will the actual conversion start? What time during the day will it take place? If it is out of hours, there may be expense related
46、 concerns of work force adjustments. Times may have to be correlated with traffk volumes dependent upon trunk capacity. Recommendation M.4100 (05/96) 3 ITU-T RECMN*M*4100 96 M 4862573 0637794 671 9 - TRUNK OPERATIONS TEST - Is this the first time a specific configuration has been tested? If so, a co
47、mprehensive test plan is suggested. If not, a substantially abbreviated test procedure may be appropriate. Will transmission test be performed? - TRANSITION TRUNK REQUIREMENTS - Will a transition trunk group need to be built? It should also be determined how the trunks will be converted with minimal
48、 service interruption. One method is to create a new trunk group for the CCSS No. 7 trunks and overflow the MF trunk group to the CCSS No. 7 Group (or vice versa). Converting in this manner allows all trunks to be in service with the exception of those which are actively in the conversion process. -
49、 MAXIMUM NUMBER OF TRNKS FOR CONVERSION - During that time that the trunks are actually being converted, they will be out of service. It must be determined how many trunks can be removed from service without adversely affecting traffic. Dependencies are the size of the trunk group, spare capacity and the time of conversion. Specific identification of trunks must be coordinate between the Administrations to ensure that both Administrations are converting the same trunks at the same time. - MANUAL VS AUTOMATIC - Will any one of the two interconnecting Administrations be using a mech
