1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T G.8275/Y.1369 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1 (01/2015) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects Synchronization, quality and availabil
2、ity targets SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Transport Architecture and requirements for packet-based time and phase distribution Amendment 1 Recommendation ITU-T G.8275/Y.1369 (2013) Amendment 1 ITU-T G-SER
3、IES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND 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
4、 METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER 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.600
5、G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 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
6、 G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 Ethernet over Transport aspects G.8000G.8099 MPLS over Transport aspects G.8100G.8199 Synchronization, quality and availability targets G.8200G.8299 Service Management G.8600G.8699 ACCESS NETWORKS G.9000G.9999 For further details, please refer
7、 to the list of ITU-T Recommendations. Rec. ITU-T G.8275/Y.1369 (2013)/Amd.1 (01/2015) i Recommendation ITU-T G.8275/Y.1369 Architecture and requirements for packet-based time and phase distribution Amendment 1 Summary Amendment 1 to Recommendation ITU-T G.8275/Y.1369 (2013) adds material on assiste
8、d partial timing support. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.8275/Y.1369 2013-11-22 15 11.1002/1000/12011 1.1 ITU-T G.8275/Y.1369 (2013) Amd. 1 2015-01-13 15 11.1002/1000/12396 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address
9、 field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.8275/Y.1369 (2013)/Amd.1 (01/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecom
10、munications, information and communication technologies (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 telecommu
11、nications on a worldwide basis. The World Telecommunication 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 proce
12、dure laid down in WTSA Resolution 1. In some 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 telec
13、ommunication administration and a recognized 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 th
14、ese mandatory provisions are met. The words “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 RIGHTSITU
15、 draws attention to the possibility that the 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 membe
16、rs or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not
17、 represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 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.8275/
18、Y.1369 (2013)/Amd.1 (01/2015) 1 Recommendation ITU-T G.8275/Y.1369 Architecture and requirements for packet-based time and phase distribution Amendment 4 1) Abbreviations and acronyms Add the following abbreviations to clause 4: APTS Assisted Partial Timing Support APTSC Assisted Partial Timing Supp
19、ort Clock PTS Partial Timing Support 2) Clause 7 2.1) Update to referencing text on assisted partial timing support Replace the following text in clause 7.1: The architecture described in this Recommendation describes the case where all of the nodes in the transmission path will provide timing suppo
20、rt by participating in the timing protocol. This is termed “full timing support to the protocol level“ (see ITU-T G.8260). The current version of this Recommendation describes an architecture for this case (full timing support to the protocol level), where all the intermediate nodes are T-BCs with p
21、hysical layer frequency support. Transparent clocks are being studied and may be included in future versions of this Recommendation. Other architectures where not all of the nodes need to provide timing support by participating in the timing protocol are for further study and may be included in futu
22、re versions of this Recommendation. This is termed “partial timing support to the protocol level“ (see ITU-T G.8260). These are for further study. Some initial considerations for this topic are documented in Appendix I. With: The architecture described in this Recommendation describes two cases; the
23、 first case is where timing support is provided by all nodes in the network (e.g., T-BCs) with physical layer frequency support (“full timing support to the protocol level“ (see ITU-T G.8260) and the second case is where intermediate nodes do not provide timing support, but timing support is provide
24、d by GNSS at the network edge, with PTP acting as a backup. This is termed assisted partial timing support (APTS). The node providing support at the edge of the network is called an assisted partial timing support clock (APTSC). Other architectures where not all of the nodes need to provide timing s
25、upport by participating in the timing protocol are termed “partial timing support to the protocol level“ (PTS) (see ITU-T G.8260). Some additional considerations for this topic are documented in Appendix I. The use of transparent clocks (TCs) are being studied and may be included in future versions
26、of this Recommendation. 2.2) Additional cases to be added covering APTS Renumber Figure 5 as Figure 5a and replace the following text in clause 7.2.1: The use of T-GM to distribute phase/time between different cell sites is for further study. 2 Rec. ITU-T G.8275/Y.1369 (2013)/Amd.1 (01/2015) With: T
27、he use of T-GM to distribute phase/time between different cell sites is for further study. Case E: APTSC at the cell sites with distributed PRTC+GM protection in aggregation sites Figure 5b APTS architecture with PRTC functions distributed in aggregation sites In this architecture, the APTSC functio
28、n is located directly at the cell site; in addition PRTC+GMs are located at the aggregation sites and distribute PTP streams to the APTSCs. These PTP streams are used by the APTSC in case of PRTC/GNSS outage. This architecture implies deployment of a higher number of GNSS receivers than in the “cent
29、ralized PRTC“ architectures. But the PTP unaware or partially aware networks can be kept as short as possible in order to decrease the asymmetry and PDV introduced by the network. Case F: APTSC at the cell sites with distributed PRTC protection at cell sites Figure 5c APTS architecture with PRTC+GM
30、functions distributed at cell sites In this architecture, the APTSC function is located directly at the cell site; in addition GMs are located at selected cell sites and distribute PTP streams to the adjacent APTSCs. These PTP streams are used by the APTSC in case of a PRTC/GNSS outage. This archite
31、cture implies deployment of a higher number of GNSS receivers than in the “centralized PRTC“ architectures, but the PTP unaware or partially aware networks can be kept as short as possible in order to decrease the asymmetry and PDV introduced by the network. In addition the GNSS signal available to
32、the APTSC in the cell site is used by the collocated GM. 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.30
33、0Y.399 Interfaces and protocols 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
34、capabilities and resource management Y.1200Y.1299 Transport Y.1300Y.1399 Interworking 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 N
35、ETWORKS Frameworks and functional 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.23
36、99 Network management Y.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 det
37、ails, please refer to the list of ITU-T Recommendations. Printed in Switzerland Geneva, 2015 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
38、 F Non-telephone telecommunication 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 sign
39、als Series K Protection against interference Series L Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Mainte
40、nance: international sound programme and television transmission circuits Series O Specifications 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
41、 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
