1、 International Telecommunication Union ITU-T G.8263/Y.1363TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(08/2013) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects Quality and availability targets SERIES Y: GLOBAL INFORMATION INFRASTRUC
2、TURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Transport Timing characteristics of packet-based equipment clocks Amendment 1 Recommendation ITU-T G.8263/Y.1363 (2012) Amendment 1 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AN
3、D NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CA
4、RRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.8
5、99 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 Ethernet over
6、 Transport aspects G.8000G.8099 MPLS over Transport aspects G.8100G.8199 Quality and availability targets G.8200G.8299Service Management G.8600G.8699 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.8263/Y.1363 (2012)/Amd.1 (08/2013) i
7、 Recommendation ITU-T G.8263/Y.1363 Timing characteristics of packet-based equipment clocks Amendment 1 Summary Amendment 1 to Recommendation ITU-T G.8263/Y.1363 (2012) adds clarification to several clauses and introduces Appendix IV “Variable temperature testing methodology“. History Edition Recomm
8、endation Approval Study Group Unique ID*1.0 ITU-T G.8263/Y.1363 2012-02-13 15 11.1002/1000/11524-en 1.1 ITU-T G.8263/Y.1363 (2012) Amd. 1 2013-08-29 15 11.1002/1000/12014-en _ *To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the
9、Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.8263/Y.1363 (2012)/Amd.1 (08/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication t
10、echnologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-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 Te
11、lecommunication Standardization Assembly (WTSA), which meets every four 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 WTSA Resolution 1. In some
12、 areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized
13、 operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words
14、“shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that th
15、e practice or implementation of this Recommendation 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
16、development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are there
17、fore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2014 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.8263/Y.1363 (2012)/Amd.1 (08/2013) 1 Recommendation
18、ITU-T G.8263/Y.1363 Timing characteristics of packet-based equipment clocks Amendment 1 1) Clause 6.1 Change the following sentence in clause 6.1 from: When temperature effects are included, the allowance for the total MTIE contribution increases by the values in Table 2. to: When temperature effect
19、s are included, the limits are given in Table 2. Replace the current Table 2 with: Table 2 Wander generation (MTIE) for PEC-S-F with temperature effects MTIE limit (ns) Observation interval (s) 1000 0.1 100 (Note) Add the following note as “NOTE 2“ after NOTE 1: NOTE 2 When testing under the worst c
20、ase temperature variation and depending on the time constant of the loop, the ageing characteristics of the oscillator may add an additional noise at the output of PEC-S-F that may slightly exceed the variable temperature mask. 2) Clause 7.1 Change the following bullet in clause 7.1 from: The limits
21、 defined for Case 3 in clause 7.2.2 of ITU-T G.8261.1, as defined in reference point D in Figure 3 of ITU-T G.8261.1, or to: The limits defined for Case 3 in clause 7.2.2 of ITU-T G.8261.1, as defined in reference point D in Figure 3 of ITU-T G.8261.1, where n=16 ppb as shown in Table 1 of ITU-T G.8
22、261.1 and Figure 4 of ITU-T G.8261.1, 3) Clause 8 Change the following note from: NOTE This specification for holdover applies assuming that there is no frequency offset before entering holdover. Other cases are for further study. to: NOTE This specification for holdover assumes that an ideal input
23、was applied to the PEC-S-F before entering holdover. 2 Rec. ITU-T G.8263/Y.1363 (2012)/Amd.1 (08/2013) 4) Clause 8.1 Remove the following text: The second derivative of x(S), the fractional frequency drift, should, over any period of S seconds, meet the following: ()() 222ns/s dS/Sxd d Change the fo
24、llowing sentence from: In applying the above requirements for the derivative of x(S) and the second derivative of x(S), the period S must begin after any transient associated with entry into hold-over is over. to: In applying the above requirements for the derivative of x(S), the period S must begin
25、 after any transient associated with entry into hold-over is over. Remove the following text: NOTE 5 d represents the maximum temporary frequency drift rate at constant temperature allowed during hold-over. However, it is not required that d and b be equal. Remove “d (ns/s2)“ from Table 3. 5) Append
26、ix IV Add Appendix IV “Variable temperature testing methodology“ after Appendix III. Appendix IV Variable temperature testing methodology (This appendix does not form an integral part of this Recommendation.) Where variable temperature testing is required, it should be conducted using the temperatur
27、e profile shown in Figure IV.1. G.8263-Y.1363(12)-Amd.1(13)_FIV.1tstLtLtLtLtLTT/tTFigure IV.1 Temperature profile The test should be repeated at different test reference temperatures, T, to cover the required temperature range. As a minimum the tests should be performed at nominal and temperature ex
28、tremes, i.e., the reference temperature T set to Tmin + T, Tnom and Tmax T. The test stabilisation time tsshould be long enough to remove start-up effects. The loop recovery time tLis dictated by the loop time constant and should be as a minimum three times the loop time constant to allow the loop t
29、o recover. Rec. ITU-T G.8263/Y.1363 (2012)/Amd.1 (08/2013) 3 The constrained temperature excursion T and the ramp rate T/t should aligned to the environmental profile. As an example, the constrained temperature excursion T could be set to 20C and the ramp rate T/t to 0.5C/minute, if these are the ap
30、plicable environmental condition. ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.199 Services, applications and middleware Y.200Y.299 Network aspects Y.300Y.399 Interfaces and p
31、rotocols Y.400Y.499 Numbering, addressing and naming Y.500Y.599 Operation, administration and maintenance Y.600Y.699 Security Y.700Y.799 Performances Y.800Y.899 INTERNET PROTOCOL ASPECTS General Y.1000Y.1099 Services and applications Y.1100Y.1199 Architecture, access, network capabilities and resour
32、ce management Y.1200Y.1299 Transport Y.1300Y.1399Interworking Y.1400Y.1499 Quality of service and network performance Y.1500Y.1599 Signalling Y.1600Y.1699 Operation, administration and maintenance Y.1700Y.1799 Charging Y.1800Y.1899 IPTV over NGN Y.1900Y.1999 NEXT GENERATION NETWORKS Frameworks and f
33、unctional architecture models Y.2000Y.2099 Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Service aspects: Interoperability of services and networks in NGN Y.2250Y.2299 Enhancements to NGN Y.2300Y.2399 Network management Y.
34、2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Packet-based Networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999 FUTURE NETWORKS Y.3000Y.3499 CLOUD COMPUTING Y.3500Y.3999 For further details, please refer to th
35、e list of ITU-T Recommendations. Printed in Switzerland Geneva, 2014 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecom
36、munication 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 television, sound programme and other multimedia signals Series K Protection
37、against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifi
38、cations of measuring equipment Series P Terminals and subjective and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission 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, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
