Table of Contents

�1���� Scope����������
�2���� References�
�3���� Definitions�
������� 3.1���� Terms defined elsewhere�����������
������� 3.2���� Terms defined in this Recommendation�
�4���� Abbreviations and acronyms
�5���� Conventions�������������
�6���� General�������
������� 6.1���� Packet network synchronization requirements����
������� 6.2���� TDM timing requirements����������
������� 6.3���� Synchronization network engineering in packet networks
������� 6.4���� Timing requirements at edge versus timing requirements in core networks�
������� 6.5���� PNT domain and CES domain���
7���� Reference timing signal distribution over packet networks (PNT domain)������������
������� 7.1���� Plesiochronous and network synchronous methods�����������
������� 7.2���� Packet-based methods�
�8���� Timing recovery for constant bit rate services transported over packet networks (CES domain)����
������� 8.1���� Network synchronous operation��������������
������� 8.2���� Differential methods����
������� 8.3���� Adaptive methods��������
������� 8.4���� Reference clock available at the TDM end systems�����������
�9���� Network limits����������
������� 9.1���� CES network limits�������
������� 9.2���� PNT network limits������
10���� Impact of impairments in the packet network on timing distribution and service clock recovery����
������ 10.1���� Packet transfer delay and delay variation������������
�� ����10.2���� Impacts from packet impairments����������
11���� Impact of the reference clock impairment on the service clock recovery�������������
������ 11.1���� Impairments for the network synchronous operation methods������
������ 11.2���� Impairments for the differential method��������������
12���� Results and consequences of the different synchronization methods over packet network reference models����
������ 12.1���� CES domain recommendations
������ 12.2���� PNT domain recommendations
Annex A � Proposed network architecture for synchronous Ethernet����
������� A.1���� PRC Location
������� A.2���� Limiting jitter and wander of synchronous Ethernet���������
������� A.3���� Considerations on the design of synchronization network based on synchronous Ethernet����
������� A.4���� Example of timing distribution via synchronous Ethernet��������������
������� A.5���� Interworking of Ethernet and synchronous Ethernet interfaces�����
Annex B � IWF functional partitioning into CES and PNT IWF and network examples����
������� B.1���� General�����������
������� B.2���� IWF clocks�����
������� B.3���� Network examples�������
Annex C � CES IWF synchronization related requirements����
������� C.1���� Traffic interfaces���������
������� C.2���� Synchronization interfaces�������
������� C.3���� IWF synchronization function��
Annex D � Network applications and requirements for clocks specified� in ITU-T G.8262/Y.1362����
Appendix I � Characteristics of Ethernet switches, Ethernet networks, routers and access technologies����
������� I.1���� Characteristics of Ethernet switches and networks�������������
������� I.2���� Delay characteristics of routers�
������� I.3���� Delay characteristics of access technologies (Microwave nodes, PON, DSL)�������������
Appendix II � Stabilization period����
Appendix III � Considerations on packet-based methods����
Appendix IV � Applications and use cases����
������ IV.1���� �Background��
������ IV.2���� Wireless���������
������ IV.3���� Infrastructure
������ IV.4���� Media gateway�������������
Appendix V � Packet networks reference models����
������� V.1���� Ethernet networks models���������
������� V.2���� Other network models�
Appendix VI � Measurement guidelines for packet-based methods����
������ VI.1���� Measurement reference points�
������ VI.2���� Input traffic characteristics������
������ VI.3���� Test topologies for adaptive methods����
������ VI.4���� Test Topologies for differential methods�������������
������ VI.5���� Test for two-way protocols�������
Appendix VII � Wander limits in Deployment Case 1����
����� VII.1���� Limits for the 2048 kbit/s interface�������
����� Page
����� VII.2���� Limits for the 1544 kbit/s interface�������
Appendix VIII � Synchronization status messaging in synchronous Ethernet PHY����
Appendix IX � IWF examples����
Appendix X � Considerations on measurement of synchronous Ethernet according to ITU-T methodologies in comparison with IEEE jitter measurements����
Appendix XI � Relationship between requirements contained in this Recommendation� and other key synchronization related Recommendations����
Appendix XII � Basic principles of timing over packet networks����
����� XII.1���� General����������
����� XII.2��� �Packet delay variation mitigation by packet selection�����
����� XII.3���� Comparison of packet-based and synchronous PHY methods�������
����� XII.4���� Existing standards������
Appendix XIII � Evaluation of the packet delay variation generation in a network node����
���� XIII.1���� Introduction�
���� XIII.2���� General considerations������������
��� XIII.3 �����General configuration��������������
Bibliography����