1、 STD-ITU-T RECMN G.824-ENGL ZOO0 4862573 0688367 215 INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STAN DARD IZATION SECTOR OF ITU G.824 (0312 O 00) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital transmission systems - Digital networks - Quality and av
2、ailability targets The control of jitter and wander within digital networks which are based on the 1544 kbits hierarchy ITU-T Recommendation G.824 (Formerly CCITT Recommendation) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesITU-T G-S
3、ERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS TRANSMISSION SYSTEMS INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE
4、METALLIC LINES COORDINATION OF RADIOTELEPHONY AND LME TELEPHONY TERMINAL EQUIPMENTS DIGITAL NETWORKS GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER- SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH General aspects G. 1004.199 G.2M.299 G.30M.399 G.400-G.449 G.450-G.499 G.70O
5、-G.799 G.800-G.899 G.800-G.809 SDH network characteristics G.84O-G.849 Management of transport network G.8504.859 SDH radio and satellite systems integration G.860-G.869 pticai transport networks G.87GG.879 G.900-G.999 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM - For Jurther details, please rejir to t
6、he list of ITU-TRecommendations. COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesThe control of jitter and wander within digital networks which are based on the 1544 kbis hierarchy Summary This ITU-T Recommendation specifies the maximum
7、 network limits of jitter and wander that shall not be exceeded at relevant transport or synchronization network interfaces and the minimum equipment tolerance to jitter and wander that shall be provided at any relevant synchronization or transport interface. The requirements for jitter and wander c
8、haracteristics that are specified in this ITU-T Recommendation must be adhered to ensure interoperability of equipment produced by different manufacturers and satisfactory network performance. Source ITU-T Recommendation G.824 was revised by ITU-T Study Group 13 (1997-2000) and approved under the WT
9、SC Resolution 1 procedure on 1 O March 2000. Keywords Clocks, input jitter tolerance, input wander tolerance, network limits, output jitter, output wander, synchronization, timing. COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesSTD-ITU
10、-T RECMN G.824-ENGL 2000 Li86259L Ob88372 BOT m FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studyin
11、g 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 four years, establishes the topics for study by the ITU-T study group
12、s which, in turn, produce Recommendations on these topic s. 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 necessary standards are prepared on a collaborative basis with I
13、S0 and IEC. NOTE In this Recommendation, 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 the possibility that the practice or implementation of this Reco
14、mmendation 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 the Recommendation development process. As of the date of ap
15、proval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TS
16、B patent database. O ITU 2001 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. COPYRIGHT International Telecommunications Union/ITU T
17、elecommunicationsLicensed by Information Handling Services 1 2 3 4 5 5.1 5.2 5.3 6 6.1 6.2 7 7.1 7.2 7.3 STD-ITU-T RECMN G-824-ENGL ZOO0 4862591 0688373 746 CONTENTS Scope References Definitions Abbreviations . Network limits for jitter and wander at traffic interfaces . Jitter limits Wander limits
18、. 5.2.1 5.2.2 Phase transients Network limits for jitter and wander at synchronization interfaces . Network limits for jitter Network limits for wander 6.2.1 Primary Reference Clock (PRC) output 6.2.2 1544 kbit/s reference interface Tolerance of jitter and wander at network interfaces . Basic specif
19、ication philosophy . 7.2.1 1544 kbit/s input jitter and wander tolerance 7.2.2 6312 kbit/s input jitter and wander tolerance 7.2.3 32 064 kbit/s input jitter and wander tolerance . 7.2.4 7.2.5 97 728 kbids input jitter and wander tolerance . Jitter and wander tolerance of clock input ports . Synchro
20、nous 1544 kbit/s network interface Synchronous 44 736 kbit/s network interface . Jitter and wander tolerance of traffic input ports 44 736 kbit/s input jitter and wander tolerance . m Page 1 1 2 3 4 4 5 5 5 6 6 6 6 6 7 9 9 9 10 11 12 13 14 15 Annex A . Wander reference models and wander budgets . 16
21、 A . 1 1544 kbit/s wander accumulation . 16 17 A.2 44 736 kbit/s wander accumulation 18 A.l.l 1544 kbit/s wander accumulation and slip simulation model assumptions COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesSTD-ITU-T RECMN G*aZg-EN
22、GL 2000 4862571 Ob8837q b82 = Introduction and background In a transport network, jitter and wander accumulate on data paths according to the jitter and wander generation and transfer characteristics of each piece of equipment interconnected. This equipment may include different types of multiplexer
23、s/demultiplexers, cross-connects and line systems, for example. An excessive amount of jitter and wander can adversely affect both digital signals (e.g. by generation of bit errors, uncontrolled slips and other abnormalities) and analogue signals (e.g. by unwanted phase modulation of the transmitted
24、 signal). The consequences of such impairment will, in general, depend on the particular service that is being carried and the terminating or adaptation equipment involved. It is therefore necessary to set limits on the magnitude of jitter and wander at network interfaces, in order to guarantee prop
25、er quality of the transmitted signals and a proper design of the equipment. COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesSTD ITU-T- RECMN G 824-ENGL 2000 = 4862593 Ob88375 519 D ITU-T Recommendation 6.824 The control of jitter and wa
26、nder within digital networks which are based on the 1544 kbit/s hierarchy 1 Scope This ITU-T Recommendation specifies the relevant parameters and their limiting values that are able to satisfactorily control the amount of jitter and wander present at synchronous digital hierarchy (SDH) and plesiochr
27、onous digital hierarchy (PDH) network-node interfaces (“I) based on the 1544 kbit/s hierarchy. An excessive amount of jitter and wander can adversely affect both digital (generation of bit errors, uncontrolled slips) and analogue signals (unwanted phase modulation of the transmitted signal). It is t
28、herefore necessary to set limits to the presence of jitter and wander at the network interfaces, in order to guarantee a proper quality of the transmitted signals. The scope of this ITU-T Recommendation is to define the parmeters and the relevant values that are able to control satisfactorily the am
29、ount of jitter and wander present at PDH network interfaces. The electrical characteristics of the relevant network interfaces are described in ITU-T Recommendation G.703. The jitter and wander control philosophy is based on the need: a) b) c) to recommend a maximum network limit that should not be
30、exceeded at any relevant interface (i.e. jitter and wander transfer, generation, and tolerance); to recommend a consistent fiamework for the specification of individual digital equipment; to provide sufficient information and guidelines for organizations to measure and study jitter and wander accumu
31、lation in any network configuration. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and ot
32、her references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid IW-T Recommendations is regularly published. 13
33、 ITU-T Recommendation G.703 (1 998), Physical/electrical characteristics of hierarchical digital interfaces. 2 CCITT Recommendation G.743 (1988), Second order digital multiplex equipment operating at 63 I2 kbit/s and using positive justiJcation. 3 4 CCI“ Recommendation G.752 (1988), Characteristics
34、of digital multiplex equipment based on a second order bit rate of 6312 kbit/s and using positive justjcation. ITU-T Recommendation G.783 (1 997), Characteristics of synchronous digital hierarchy (SDH) equipment finctional blocks. 5 6 CCITT Recommendation G.801 (1988), Digital transmission models. I
35、TU-T Recommendation G.803 (2000), Architecture of transport networks based on the Synchronous Digital Hierarchy (SDH). . COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services- synchronization networks are provided in ITU-T Recommendation G.8
36、 10. 3.1 synchronous interface: For the purpose of this ITU-T Recommendation, a synchronous interface is defined such that the bit rate of the interface is derived fiom a source that is ultimately traceable to a PRC. 3.2 asynchronous interface: These interfaces provide an output signal with frequenc
37、y that is not traceable to a PRC and that meets the fiequency offset requirements given in ITU-T Recommendation G.703. 3.3 traffic interface: These interfaces may be synchronous (Le. normally PRC-traceable) or asynchronous (i.e. meeting the frequency offset requirements of ITU-T Recommendation G.703
38、) and network limits are specified using the MRTIE (Maximum Relative Time Interval Error) parameter in this ITU-T Recommendation. Input jittedwander tolerance is also specified in this ITU-T Recommendation. This interface category can be further sub-divided as follows: a) Interface is not able or re
39、quired to provide synchronization. An example is an interface supporting only 44 736 kbit/s PDH signals according to ITU-T Recommendation G.703. b) Interface is not able to provide synchronization at the defined performance level, but nevertheless is used to provide timing to other network elements
40、such as terminal equipment, remote concentrators, etc. Examples include 1544 and 44 736 kbit/s PDH signals STD=ITU-T RECMN G-824-ENGL Z m 48b259L b8837b 455 ITU-T Recommendation G.8 1 O (1 996), Definitions and terminology for synchronization networks. ITU-T Recommendation G.811 (1997), Timing chara
41、cteristics of primaly reference clocks. ITU-T Recommendation G.812 (1998), Timing requirements for slave clocks suitable for use as node clocks in synchronization networks. ITU-T Recommendation G.8 13 (1 996), Timing characteristics of SDH equipment slave clocks (SEC). CCITT Recommendation G.822 (1
42、988), Controlled slip rate objectives on an international digital connection. ITU-T Recommendation G.823 (2000), The control of jitter and wander within digital networks which are based on the 2048 kbith hierarchy. ITU-T Recommendation G.825 (2000), The control of jitter and wander within digital ne
43、tworks which are based on the synchronous digital hierarchy (SDH). ITU-T Recommendation G.957 (1999), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. ITU-T Recommendation 1.43 1 (1 993), Primaly rate user-network interface - Layer I specification. ITU-T R
44、ecommendation O. 150 (1996), General requirements for instrumentation for performance measurements on digital transmission equipment. ITU-T Recommendation O. 171 (1997), Timing jitter and wander measuring equipment for digital systems which are based on the Plesiochronous Digital Hierarchy(PDH). ITU
45、-T Recommendation O. 172 (1 999), Jitter and wander measuring equipment for digital systems which are based on the synchronous digital hierarchy (SDH). ITU-T Recommendation 4.541 (1993), Digital exchange design objectives - General. Definitions ITU-T Recommendation defines the following terms. Addit
46、ional definitions relating to COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesSTDIITU-T RECMN G.Bi?q-ENGL 2OOO 48b259L Ob88377 39s transported on SDH, which may be subject to pointer justifications. ITU-T Recommendation G.803 recommends
47、 that these interfaces not be used for synchronization. c) Interface is able to provide synchronization at the defined performance level, in which case it is defined to be a synchronization interface. 3.4 synchronization interface: These interfaces are synchronous (i.e. normally PRC-traceable) and s
48、uitable for timing network clocks (SSUs and SECS). The network limits for synchronization interfaces are specified using MTIE (Maximum Time Interval Error) and TDEV (Time Deviation) parameters with values given in this ITU-T Recommendation. The input jittedwander tolerance of clock equipment ports i
49、s specified in ITU-T Recommendation G.812 (for equipment containing an SSU function) and Option 2 of ITU-T Recommendation G.813 (for equipment containing an SEC function). 3.5 phase transient: Perturbations in phase of limited duration seen at synchronization and trafc interfaces, which may be due to clock switching or pointer justifications. The duration of phase transients caused by clock switching depends upon the clock involved. A G.813 clock may have a transient that has duration in the range of milliseconds to seconds, while a G.812 clock transient may take h
