1
Scope
2 References
3 Terms and definitions
4 Abbreviations and acronyms
5 Synchronization principles
5.1 Network synchronization
5.2 Synchronization distribution trails
5.3 Synchronization interfaces
5.4 Clock-source quality-level
5.5 Synchronization status messages (SSMs) and timing marker (TM)
channels
5.6 Selection process
5.7 Signal fail
5.8 Hold-off time
5.9 Wait to restore time
5.10 Synchronization source priorities
5.11 External commands
5.12 Automatic reference selection process
5.13 Timing loop prevention
5.14 Delay times for NEs with SEC/ST3/SIC
5.15 Delay times for NEs with SSU/ST2 or for SASE/BITS
5.16 Synchronization layer functions
5.17 Overview of the processes performed within the atomic functions
5.18 Interworking between option I, II and III synchronization
networks
6 Synchronization distribution layer atomic functions
6.1 SD connection function (SD_C)
6.2 SD trail termination functions
6.3 SD adaptation functions
7 Network synchronization layer atomic functions
7.1 NS_connection functions (NS_C)
8 Transport layer to SD layer atomic functions
8.1 STM‑n multiplex section adaptation functions
8.2 Pqs adaptation functions
8.3 P12s layer adaptation functions
8.4 T12 layer adaptation functions
8.5 P11s layer adaptation functions
8.6 T01
layer adaptation functions
8.7 T02
layer adaptation functions
8.8 T21
layer adaptation functions
8.9 ETH
layer adaptation functions
9 Equipment clock to transport layers clock
adaptation functions
9.1 STM-N layer
9.2 VC layers
9.3 Pxx
layers
9.4 T12
layer
9.5 T01
layer
9.6 T02
layer
9.7 T21
layer
9.8 ETYn
layer
10 T12
section layer functions
10.1 T12
connection function T12_C
10.2 T12
trail termination functions
11 T01
section layer functions
11.1 T01
connection function T01_C
11.2 T01
trail termination functions
12 T02
section layer functions
12.1 T02
connection function T02_C
12.2 T02
trail termination functions
13 T21
section layer functions
13.1 T21
connection function T21_C
13.2 T21 trail termination functions
Annex A – Synchronization selection process
Appendix I – Transport layer models for synchronization information
Appendix II – Examples of synchronization functionality in the NE
II.1 Examples of synchronization functionality in the NE for
option I networks
II.2 Examples of synchronization functionality in the NE for
option II networks
II.3 Examples of synchronization functionality in the NE for
option III networks
Appendix III – Delay time allocation for option I and III networks
III.1 Delay and processing times for the synchronization selection
process
III.2 Non‑switching message delay TNSM
III.3 Switching message delay TSM
III.4 Holdover message delay THM
III.5 Wait to restore time TWTR
Page
Appendix IV – Interworking of option II equipment
supporting second generation SSM and first generation SSM using a translation
function
Bibliography