1
Scope
2 References
3 Terms and definitions
4 Abbreviations
5 General description of
international synchronous digital leased circuits
5.1 Leased circuit configuration
5.2 Network interfaces
5.3 Timing and network synchronization
5.4 Designations
5.5 Performance
6 Operational procedures
6.1 Control and sub-control stations
6.2 BIS procedures
6.2.1 Section‑by‑section testing and In‑Service Monitoring
(ISM)
6.2.2 National circuit portions
6.2.3 International circuit portions
6.2.4 BIS using an alternative international link
6.2.5 End-to-end test
6.2.6 Alternative end-to-end test
6.3 Maintenance procedures
6.3.1 Performance monitoring and data collection
6.3.2 Performance history, thresholding and reporting
6.3.3 Maintenance intervention tests
6.3.4 Test configurations
6.3.5 Test access at DCS equipment
6.3.6 Returning-to-service tests
6.3.7 Planned maintenance
7 Maintenance records
8 Protection and reserve
arrangements
Annex A - Fault
management
A.1 Initial reception of a fault
report
A.2 Fault information exchange
A.3 Fault localization
A.4 Circuit restoration
A.5 Temporary service restoration
A.5.1 Mechanisms for implementing temporary service restoration
A.5.2 Time to restore service
A.5.3 Restoration procedure
A.5.4 Returning to normal routing
A.5.5 Information that should be exchanged
A.6 Automatic rerouting of
international SDH transmission links
A.7 Precautions to be taken in the use
of DCSs