1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 % TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%0(/.%G0G0.%47/2+G0G0!.$G0G0)3$./0%2!4)/. G0G0.5-“%2). G0G02/54).!.$G0G0-/“),%G0G03%26)#%2/54).G0G0/&G0G042!&)#G0G0“9G0G0!54/-!4)#42!.3)4G0G0%8#(!.%3)45G134G0G0RecommendationG0G0% (Extract from the “LUEG0“
2、OOK)NOTES1 ITU-T Recommendation E.148 was published in Fascicle II.2 of the Blue Book. This file is an extract from theBlue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and c
3、opyright conditions remain unchanged (see below).2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or
4、 utilized in any form or by any means, electronic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle II.2 - Rec. E.148 1Recommendation E.148Fascicle II.2 - Rec. E.148ROUTING OF TRAFFIC BY AUTOMATIC TRANSIT EXCHANGESIn the two cases mentioned herea
5、fter it may be advantageous from a general economic point of view (takinginto account the loss probability and cost) to route traffic by automatic transit exchanges:Case 1Where there is a light traffic load between two countries, it may be desirable to route this traffic through anautomatic transit
6、exchange, rather than to provide a small group of direct circuits.The considerations normally apply to the case where the introduction of semiautomatic operation is considered,but they should be equally valid for traffic which terminates on a manual international trunk exchange, reachedthrough an au
7、tomatic transit exchange.Note The purely economic point of view from which these conclusions are drawn excludes all otherconsiderations, particularly the following:a) It is necessary that the transit exchanges through which it is desired to route the traffic should be preparedto accept the transit t
8、raffic which would be offered to them and Administrations involved should designtheir circuit groups to satisfy the requirements of Part II of Fascicle II.3 in so far as loss probability isconcerned.b) The provision of direct circuits may be preferred to a routing entirely via a transit centre for o
9、ther reasons,e.g. the provision of broadcast programme circuits, control circuits for these transmissions, voice-frequencytelegraph circuits, etc.Case 2In certain cases, particularly where the traffic between two countries is heavy, and when, for instance, it maylead to the deferment of a new installation, it may be advantageous to route a certain proportion of theadditional traffic (peak traffic) by way of a transit automatic centre.
