WDM Clock Signal Flow

Signal Flow of WDM NE Clock Tracing

When you plan clock tracing between NEs in a network, the equipment in the entire network must trace the same clock source. For the WDM equipment, you need to set a station (usually the center station) to use its own internal clock source, and other stations all trace this clock source. Figure 1 illustrates the clock tracing relationship between NEs on a ring that consists of WDM equipment.

Figure 1 Clock Synchronization

In a WDM network, clock signals are transmitted in the optical supervisory signals by the OSC board (including SC1/SC2), and transmitted to the SCC board for processing. During configuration, you need to set clock source priority for the SCC board at each station, and set a returned clock for the OSC board. That is, set the OSC board to send east or west clock signals to the SCC board. Generally, set the highest priority level for the external clock signal that is transmitted in supervisory signals. Figure 2 illustrates the clock tracing relationship and clock signal flow between NEs in a transmission line that consists of WDM equipment.

Figure 2 Signal flow of NE clock tracing

NOTE:

The previously mentioned three optical NEs contain other NEs, and the NEs have no supervisory channel. By default, the NEs that have no supervisory channels use the internal clock sources.