1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Series E.800 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 5 (11/1988) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Telephone network management and traffic engineering Teletraffic implications f
2、or international switching and operational procedures resulting from a failure of a transmission facility ITU-T E.800-series Recommendations Supplement 5 (Formerly CCITT Recommendations) ITU-T E-SERIES RECOMMENDATIONS OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS
3、INTERNATIONAL OPERATION Definitions E.100E.103 General provisions concerning Administrations E.104E.119 General provisions concerning users E.120E.139 Operation of international telephone services E.140E.159 Numbering plan of the international telephone service E.160E.169 International routing plan
4、E.170E.179 Tones in national signalling systems E.180E.189 Numbering plan of the international telephone service E.190E.199 Maritime mobile service and public land mobile service E.200E.229 OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE Charging in
5、the international telephone service E.230E.249 Measuring and recording call durations for accounting purposes E.260E.269 UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS General E.300E.319 Phototelegraphy E.320E.329 ISDN PROVISIONS CONCERNING USERS E.330E.349 INTERNA
6、TIONAL ROUTING PLAN E.350E.399 NETWORK MANAGEMENT International service statistics E.400E.409 International network management E.410E.419 Checking the quality of the international telephone service E.420E.489 TRAFFIC ENGINEERING Measurement and recording of traffic E.490E.505 Forecasting of traffic
7、E.506E.509 Determination of the number of circuits in manual operation E.510E.519 Determination of the number of circuits in automatic and semi-automatic operation E.520E.539 Grade of service E.540E.599 Definitions E.600E.649 Traffic engineering for IP-networks E.650E.699 ISDN traffic engineering E.
8、700E.749 Mobile network traffic engineering E.750E.799 QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING Terms and definitions related to the quality of telecommunication services E.800E.809 Models for telecommunication services E.810E.844 Objectives for
9、quality of service and related concepts of telecommunication services E.845E.859 Use of quality of service objectives for planning of telecommunication networks E.860E.879 Field data collection and evaluation on the performance of equipment, networks and services E.880E.899 For further details, plea
10、se refer to the list of ITU-T Recommendations. E.800 series Supplement 5 (11/1988) i Supplement 5 to ITU-T E.800-series Recommendations Teletraffic implications for international switching and operational procedures resulting from a failure of a transmission facility Source Supplement 5 was approved
11、 in Melbourne (1988) and originally published in Blue Book, Fascicle II.3. ii E.800 series Supplement 5 (11/1988) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (IT
12、U-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every fou
13、r years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSC Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the
14、 necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this publication, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to th
15、e possibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of t
16、he publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementors are cautioned that this may not represent the latest information
17、and are therefore strongly urged to consult the TSB patent database. ITU 2002 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. E.800 series Supplement 5 (11/1988) 1 Supplement 5 to ITU-T E.800-series Recommendat
18、ions Teletraffic implications for international switching and operational procedures resulting from a failure of a transmission facility 1 Very considerable changes have occurred in the international network over the past decade. These changes have arisen mainly from: the growth in the number of lon
19、g-distance routes; the growth in the number of circuits forming individual long-distance routes; the world-wide introduction of international automatic operation; technological developments associated with all aspects of the international network: switching unit design, transmission facility design,
20、 and routing and operational strategies; the integration into the international automatic service of the more isolated geographical areas and of centres having low-capacity international switching units. 2 The resultant multiplicity of circumstances and situations arising within the international ne
21、twork is now such that it is no longer possible to specify one single criterion for initiating corrective action to counter the loss of a transmission facility. Indeed, the failure of the whole, or part, of a transmission facility may manifest itself in a different manner to each of several Administ
22、rations affected by the failure. 3 Among the many aspects of international switching and operational procedures which can influence the degree of curtailment of service arising from a transmission-facility failure, i.e. which can reduce the ability of part of the international network to carry its d
23、esigned traffic load successfully, the following are specifically stressed (their order has no particular significance): the introduction of fully automatic international operation, which means that the control of the network, formerly completely operator-controlled, now depends directly on subscrib
24、ers habits; the number of routes that could be affected by failure and their proportion of the total routes on the switching unit to which they are directly connected: the range can be from one whole route to a few circuits in each of many routes, depending on the method of allocating circuits to tr
25、ansmission facilities; the influence of any route, for which no alternative transmission facility exists, on the performance of the international switching unit to which it is connected; the effect on the grade of service of the switching unit itself due to the loss of a complete route or routes, or
26、 parts of several routes, directly connected to it; the methods of limiting the effect of failure on service by action within the switching unit or at preceding international or national switching unit, e.g. by code blocking or recorded announcements; the cause of the failure, and thus the possible
27、restoration time, relative to the 24-hour traffic profile; the effect of a failure on overflow and automatic alternative routing strategies; the use of diversity of international switching units; the use of diversity of international transmission facilities. 4 Attention is also drawn to four major f
28、actors of maintaining continuity of service: reliability, diversity, network management, and any redundancy specifically provided to allow restoration of service. 2 E.800 series Supplement 5 (11/1988) 5 Clearly, no practical transmission facility provided will give 100 per cent reliability, so it is
29、 inevitable that the other three factors will be involved to varying degrees in maintaining service. The interaction of these four factors will depend largely on the emphasis placed upon each of them by each Administration, thus reinforcing the view that the degree of corrective action that can be t
30、aken will depend considerably upon the investment policy (in materials and equipment) and forward-planning objectives of individual Administrations. 6 With respect to diversity, it is recommended that Administrations give consideration to the provision of an adequate number of paths for a particular
31、 route, with an adequate level of independence between the paths. Such independence could reduce the effect of a breakdown or other adverse event by confining it, as far as possible, to only one of the paths used by that route. 7 For the further assistance of Administrations in their study of those
32、teletraffic aspects of international switching and operational procedure which influence the degree of curtailment of service and which arise from a transmission facility failure, these factors are included in Question 23/II related to continuity of service, accepted for study during the 1985-1988 S
33、tudy Period. Geneva, 2002 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series B Means of expression: definitions, symbols, classification Series C General telecommunication statistics Series D General tariff principles Series E Overall network operation, telephone servi
34、ce, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of televis
35、ion, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsim
36、ile and leased circuits Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling Series R Telegraph t
37、ransmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communications Series Y Global information infrastructure and Internet protocol aspects Series Z Languages and general software aspects for telecommunication systems
