Description
In physical clock synchronization mode, WDM devices like OSN8800 restore frequency signals from physical signals such as Ethernet links, packet links, and SDH links to achieve frequency synchronization of the upstream and downstream devices. Physical clocks require the device hardware to support clock extraction. Therefore, each node must support physical-layer clocks to achieve frequency synchronization on the entire network.
Application Scenario
Physical clock (OTN): Supports synchronous Ethernet processing and synchronous Ethernet transparent transmission to implement frequency synchronization.
Synchronous Ethernet processing: The system clock performs frequency synchronization for upstream NEs one by one. Synchronous Ethernet processing can be used with IEEE 1588v2 to implement phase synchronization.
Synchronous Ethernet transparent transmission: It only transmits the clock to the destination node to guarantee clock quality. Internal free-run on the NE is implemented, and frequency is not synchronized with the upstream NE. Synchronous Ethernet transparent transmission cannot work with IEEE 1588v2 to implement phase synchronization.
Physical clock (packet): On a packet network, packet boards can be used to implement frequency synchronization.
Physical clock (SDH): In an SDH modernization scenario where the SDH network must be synchronized, SDH boards can be used to implement frequency synchronization and provide synchronization for base stations.
Figure 1 Physical clock scenarios
