1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 ) TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU).4%2!4%$G0G03%26)#%3G0G0$)4!,.%47/2+G0G0 )3$.G9)3$.G0G053%2G13.%47/2+G0).4%2&!#%3“!3)#G0G053%2G13.%47/2+G0G0).4%2&!#%)45G134G0G0RecommendationG0G0) (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation I.
2、420 was published in Fascicle III.8 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 copyright conditions remain unchan
3、ged (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 utilized in any form or by any m
4、eans, electronic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle III.8 - Rec. I.420 1Recommendation I.420Fascicle III.8 - Rec. I.420BASIC USER-NETWORK INTERFACE(Malaga-Torremolinos, 1984)The basic user-network interface structure is defined in Recommendation I.412. The detailed specifications arecontained in Recommendations I.430 (layer 1), I.440 and I.441 (layer 2), I.450, I.451 and I.452 (layer 3).
