1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU MAINTENANCE: DESIGNATIONS AND INFORMATION EXCHANGE M.1540 (1 0/94) EXCHANGE OF INFORMATION FOR PLANNED OUTAGES OF TRANSMISSION SYSTEMS ITU-T Recommendation M.1540 (Previously “CCIlT Recommendation”) ITU-T REC
2、MN*M.1540 74 4862573 O600070 760 m FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations on them with a view
3、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. The approval of Recommendat
4、ions by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). ITU-T Recommendation M.1540 was revised by ITU-T Study Group 4 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 15th of October 1994. NOTE In thi
5、s Recommendation, the expression ?Administration? is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1995 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechan
6、ical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMN*M*L540 94 48b2591 0600071 bT7 CONTENTS Page 1 General . 1 2 Planned outages of international analogue, PDH and SDH transmission systems 1 3 Planned outages of national transmission systems, which affe
7、ct international leased and special circuits 3 Reference . 3 Recommendation M.1540 (10/94) 1 ITU-T RECMN*M-I54O 911 11862573 Ob00072 533 Recommendation M.1540 EXCHANGE OF INFORMATION FOR PLANNED OUTAGES OF TRANSMISSION SYSTEMS (Published as M.221 in 1976; revised and renumbered us M.490 in 1984; rev
8、ised and renumbered as M. 1540 in 1994) 1 General Planned outages of transmission systems are required to allow planned work to be done with the minimum impairement to the service concerned. All tests, measurements, rearrangements, etc., which are not attributed directly to a failure - and are known
9、 in advance - are considered to be planned work. Such work will include installation of new equipment, routine maintenance, work on power supply equipment and in some cases, work for the clearance of faults which at first could only be remedied provisionally (mainly cable faults). In the event of pl
10、anned work which results in the complete or partial interruption in a transmission system, efforts are at first made to reroute the telecommunication traffic as required. If special restoration plans exist for cases of faults, these pians can also be used in the event of planned outages. Should rero
11、uting be impossible, planned work is generally carried out during periods of light traffic, e.g. at night. To allow appropriate measures to be taken, all stations affected by the planned outage must be informed in good time. 2 Planned outages of international analogue, PDH and SDH transmission syste
12、ms When an Administration plans the outage of an international transmission system, it should inform all other Administrations in whose territories the links terminate. This information should be given by telex, fax, etc. at least three working days in advance.l) When an outage is expected to affect
13、 QOS to a customer, it is deemed necessary to notify the Administrations at least 17 days in advance. An example is given in Figure 1. There are cases in which more than three days are necessary, such as those involving extensive rearrangements. If, in exceptional cases, a three-day notice cannot be
14、 given, advice should be given by telephone so as to ensure that the Administrations Concerned still have sufficient time to take the appropriate steps. Planned outages should not be carried out if notice cannot be given and received at least 24 hours in advance. In practice, Administrations have en
15、trusted different entities, Le. either their international centres or their technical services with the exchange of information for planned outages. Therefore, it is essential that each Administration states clearly to whom reports on outages are to be sent2). In any case, the technical service of a
16、n Administration should be aware of the outages planned in its own country, and try to reduce their impact on international services to a minimum. Passing on of the information within the area of an Administration, e.g. to the control stations for leased and special circuits, or to the users of leas
17、ed circuits, is done according to the national practice. The time limit of three working days is not intended to affect other agreements in special cases, e.g. a notification time of two weeks in planned outages of submanne cable systems. 2, Normally such information is exchanged between the System
18、Availability Information Points (see Recommendation M.721). Recommendation M.1540 (10/94) 1 2 Because of urgent work in our country the following groups and supergroups will be out of service from 20th March 23:OO to 21 st March 06:OO (gmt): ifm - luxemburg 6003 ifm - paris 6002 ifm - oslo 1202 ifm
19、- rotterdam 6002,6005 ifm - amsterdam 6002 amsterdam - budapest 1201 Ym - london 1214,1246 jusseldorf - milano 6001 *egards. FIGURE 1M.1540 Example of a telex message concerning a planned outage of international groups and supergroups Recommendation M.1540 (10/94) ITU-T RECMN*M-L540 94 m 4862591 Ob0
20、0074 306 3 Planned outages of national transmission systems, which affect international leased and special circuits In the international centres, international leased and special circuits are frequencly through-connected in the voice-frequency band and routed to the destination via national group li
21、nks. An outage of these group links leads to a break in the international circuit. In this cases, informing the circuit control station and the users is of particular importance in order to avoid unnecessary fault location in the other country. If an outage is planned for a national system within th
22、e area of the Administration being entrusted with the terminal sub-control function for a circuit, the circuit control station should be informed direct or via the two transmission maintenance points (international line) (see Recommendation M.1014 i or via the technical service so as to enable the c
23、ontrol station to inform the user in good time. In addition, it may be advisable that the terminal sub-control station informs the user as its end of the circuit of the planned outage, since an exchange of information between the users at both ends of the circuit is not always possible. Figure 2 ill
24、ustrates the possible flow of information for this case. A similar procedure should be applied if a planned outage of a national system in a transit country affects an international leased or special circuit. If an outage is planned for a national system within the area of an Administration having c
25、ontrol functions for a circuit, it is recommended that the sub-control station be advised in order to avoid unnecessary queries in the event of a fault report being submitted by the user in the distant country concerned. The transmission maintenance point (international line) in its own country shou
26、ld be informed in any case. Reference 11 CCIT Recommendation Transmission maintenance point (international line) (TMP-IL), Rec. M. 1014. Recommendation M.1540 (10/94) 3 ITU-T RECMN*M-L54O 94 4Bb259L Ob00075 242 Country A I Country B I I I I Planned outage I I I I L n n rl I I I I u u u I I I ces ti-
27、 l I, I TMP-IL I TMP-IL TCSCS Renters A I B Renters premises premises TCSCS . =.a TMP-IL B TMP-IL A I . CCS I I p-yd i i i I i L.i.,.i.i.i.iii.iii.iiiiii-iii.,*,.,.,.,.,.,.,. T0404770-94/d01 international centre 0 National repeater station CCS Circuit control statim TCSCS Terminal circuit sub-contro
28、l station TMP-IL Transmission maintenance point - Internatimal line 4- Infmation flow between TCSCS and CCS +-Additional information flow +-.-.- Infmation flow between users FIGURE uM.1540 Example of a possible information flow in case of planned outage of a national transmission system affecting an international leased circuit 4 Recommendation M.1540 (10194)
