1、 ANSI/TIA-594-B-2004 APPROVED: MARCH 18, 2004 REAFFIRMED: AUGUST 26, 2009 WITHDRAWN: JULY 24, 2015 TIA-594-B (Revision of TIA-594-A) March 2004Telecommunications Multiline Terminal Systems SynchronousMethods and Technical Requirements forPrivate Integrated Services Networks NOTICE TIA Engineering St
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20、CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. TIA-594-B i TABLE OF CONTENTS 1 INTRODUCTION. 1 2 SCOPE . 2 3 NORMATIVE REFERENCES 3 4 DEFINITIONS, ABBREVIATIONS AND ACRONYMS. 4 4.1 DEFINITIONS. 4 4.1.1 Asynchronous signals . 4 4.1.2 Clock accuracy 4 4.1.3 Clock free running mode. 4
21、 4.1.4 Clock hold over mode. 4 4.1.5 Controlled Slip 4 4.1.6 Hold-in range 4 4.1.7 Jitter. 4 4.1.8 Master clock 4 4.1.9 Maximum time interval error (MTIE). 5 4.1.10 Phase Lock Loop (PLL) . 5 4.1.11 Phase Transients . 5 4.1.12 Plesiochronous 5 4.1.13 Primary Reference Source (PRS) or Clock (PRC) . 5
22、4.1.14 Pull-in range . 5 4.1.15 Reference Clock . 6 4.1.16 Severely Errored Seconds (SES) 6 4.1.17 Slave clock 6 4.1.18 Slip 6 4.1.19 Split Timing 6 4.1.20 Synchronous . 6 4.1.21 Synchronization 6 4.1.22 Synchronization network 6 4.1.23 Time-Interval Error (TIE). 6 4.1.24 Timing Loop. 6 4.1.25 Time
23、to repair (TTR) 6 4.1.26 Transparent . 7 4.1.27 Unit Interval (UI) 7 4.1.28 Wander . 7 4.2 ABBREVIATIONS AND ACRONYMS . 8 5 GENERAL INFORMATION ON SYNCHRONIZATION 9 5.1 IMPACT OF SLIPS 9 5.2 OTHER IMPAIRMENTS . 10 6 TECHNICAL REQUIREMENTS AND SYNCHRONIZATION METHODS. 11 6.1 TECHNICAL REQUIREMENTS 11
24、 6.1.1 Jitter and wander at the input 11 6.1.2 Jitter and wander at the output 12 TIA-594-B ii 6.1.3 Frequency deviation at the input .13 6.1.4 Clock accuracy 13 6.1.5 Pull-in range and Hold-in range 14 6.1.6 Phase discontinuity of slave clocks .14 6.2 TIMING REFERENCES.14 6.2.1 Reference Clock Swit
25、ching Criteria 14 6.2.2 Reference Restoral.15 6.2.3 Timing Reference Interfaces and Alarms 15 6.2.4 Buffers .15 6.2.5 Controls .15 6.2.6 Slip performance objectives 15 6.3 SYNCHRONIZATION PLANNING GUIDE LINES IN PRIVATE DIGITAL NETWORKS .16 ANNEX A (INFORMATIVE) - SYNCHRONIZATION PERFORMANCE REQUIRE
26、MENTS FOR E1 - C2 AND T2 INTERFACES WITH 2.048 MBITS/S ACCESS 17 ANNEX B (INFORMATIVE) - SYNCHRONIZATION METHODS FOR PRIVATE DIGITAL NETWORKS .20 ANNEX C (INFORMATIVE) CONTROLLED SLIP OBJECTIVES (ISO/IEC 11573)27 ANNEX D (INFORMATIVE) - SYNCHRONIZED PRIVATE NETWORK EXAMPLES30 ANNEX E (INFORMATIVE) -
27、 SLAVE CLOCK PERFORMANCE MEASUREMENT GUIDELINES .33 ANNEX F (INFORMATIVE) BIBLIOGRAPHY.38 TIA-594-B iii FOREWORD (This foreword is not part of this standard.) This document is a TIA Telecommunications standard produced by Subcommittee TR-41.1 of Committee TR-41. This standard was developed in accord
28、ance with TIA procedural guidelines, and represents the consensus position of the Subcommittee TR-41.1, which served as the formulating group. This standard is based on ANSI/TIA/EIA-594-A, with changes to reflect technical requirements specific to North America. The TR-41.1 Multiline Terminal System
29、s Subcommittee acknowledges the contribution made by the following individuals in the development of this standard. Name: Representing: Richard Frank Dietrich Lockard Raymond Gass Alcatel Francois Pinier Alcatel Radha Telikepalli Nortel Networks Editor Tailey Tung Siemens This standard has six annex
30、es, all of which are informative. Copyrighted parts of ISO/IEC 11573 are used with permission of the ISO. The ISO owns the copyright for the ISO Standards. Suggestions for improvement of this standard are welcome. They should be sent to: Telecommunications Industry Association Engineering Department
31、 Suite 300 250 Wilson Boulevard Arlington, VA 22201 (http:/www.tiaonline.org ) TIA-594-B 1 1 Introduction When synchronous digital signals are being transported over a communications link, the receiving end must operate at the same average frequency as the transmitting end to prevent loss of informa
32、tion. This is referred to as link synchronization. When digital signals traverse a network of digital communications links, switching nodes, multiplexers, and transmission interfaces, the task of keeping all the entities operating at the same average frequency is referred to as network synchronizati
33、on. The design of a Private Integrated Services Network (PISN) requires specification of the timing sources and receivers for the synchronization network. Proper design requires that timing loops in the synchronization network be avoided. A timing loop occurs when a clock is using as its reference f
34、requency a signal that is itself traceable to the output of that clock. The information of such a closed timing loop leads to frequency instability and is not permitted. While it is relatively straightforward to ensure against timing loops in the primary synchronization reference network, care shoul
35、d be taken that timing loops do not occur during failure or error conditions when various timing references are rearranged. Further information on Private network synchronization can also be found in ISO/IEC 11573 standard. TIA-594-B 2 2 Scope This TIA Standard contains requirements necessary for th
36、e synchronization of TDM based PISNs. Timing within a digital private network needs to be controlled carefully to ensure that the rate of occurrences of slips between equipment within the PISN, and the public switched networks is sufficiently low not to affect unduly the performance of voice transmi
37、ssions, or the accuracy or throughput (if errored data require re-transmission) of non-voice services. The clock accuracy classification considered in this standard is based on North American stratum levels. Requirements are also based upon the interconnection of digital private telecommunication ne
38、tworks via digital facilities in the public (switched or packet) telecommunication networks. Synchronization in packet based networks is based on time stamping or timing protocols like Network Time Protocol (NTP). At present, time stamping based synchronization is used in ATM networks. NTP is broadl
39、y used in the Internet to synchronize distributed clocks to each other or to time server having an accurate clock (e.g. a server connected to GPS receiver). In NTP based synchronization, clock offset and skew would be estimated based on one-way delay measurement across the network, the accuracy of s
40、ynchronization depends on the network paths between two hosts. This TIA standard does not address the synchronization methods applicable to packet based networks. This Standard is one of a series of technical standards on telecommunications networks and with its companion standards fills a recognize
41、d need in the telecommunications industry brought about by the increasing use of digital equipment and facilities in private networks. It is useful to anyone engaged in the manufacture of digital customer premises equipment (CPE) for private network applications, and to those purchasing, operating o
42、r applying digital CPE to digital facilities for PISNs. This Standard establishes technical criteria necessary in the design of a synchronization plan for a PISN. Compliance with these requirements would be expected to result in a quality PISN synchronization design. TIA-594-B 3 3 Normative Referenc
43、es The following standards contain provisions, which, through reference in this text, constitute provisions of this Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Standard are encouraged to inves
44、tigate the possibility of applying the most recent editions of the standards indicated below, or their successors. ANSI and TIA maintain registers of currently valid national standards published by them.(1) ANSI T1.605-1991 (R1999): “Integrated Service Digital Network (ISDN); Basic Access Interface
45、for S and T Reference Points (Layer 1 specification)” (2) ANSI T1.403-1999: “Network and Customer Installation Interfaces DS1 Electrical Interface” (3) ANSI T1.101-1999: “Synchronization Interface Standard”. (4) ANSI T1.105.09-1996 (R2002): “Synchronous Optical Network (SONET) Network Timing and Syn
46、chronization” (5) ANSI T1.231-1997: “Digital Hierarchy Layer 1 In-Service Digital Transmission Performance Monitoring” (6) ITU-T Recommendation I.431 (03/93): “Primary rate user network interface Layer 1 specification”. (7) ITU-T Recommendation G.812 (06/98): “Timing requirements of slave clocks sui
47、table for use as node clocks in synchronization networks”. (8) ITU-T Recommendation G.811 (09/97): “Timing characteristics of primary reference clocks” (9) ITU-T Recommendation G.813 (08/96): “Timing characteristics of SDH equipment slave clocks (SEC)” (10) ITU-T Recommendation G.704 (10/98): “Synch
48、ronous frame structures used in 1544, 6312, 2048, 8448 and 44736 kbits/s hierarchical levels” (11) ITU-T Recommendation G.822 (1988): “Controlled slip rate objectives on an International digital connection” (12) ISO/IEC 11573 (1994): “Information Technology Telecommunications and information exchang
49、e between systems Synchronization methods and technical requirements for Private Integrated Services Networks” TIA-594-B 4 4 Definitions, Abbreviations and Acronyms For the purposes of this Standard, the following definitions apply. 4.1 Definitions 4.1.1 Asynchronous signals In this standard, asynchronous signals are the signals having a source of clocking that is not traceable to the same clock. 4.1.2 Clock accuracy The maximum magnitude of fractional frequency offset from the ideal frequency for a specified time period. Accuracy is usually used to define the frequency d
