This section describes how to monitor the performance of a passive interface. After a 1588v2 network achieves stable time synchronization, monitor the passive interface's offset that is between the master and slave clocks.
A passive interface is determined. The display ptp all command output contains "passive" in the State field of the Port Info part.
Passive interfaces do not trace or advertise time information. If a device has multiple master 1588v2 interfaces in the same clock domain, the device selects the interface with the highest priority as the master clock, and the interface connected to the master clock is the slave clock. Other local interfaces are passive interfaces that function as backups for the slave clock. Passive interfaces can send Delay_Req, Pdelay_Resp, Delay_Resp_Follow_Up, signaling, and management response messages.
On a dynamic 1588v2 network, a passive interface may change to be a slave clock or a master clock to participate in time synchronization after a clock source changes. Monitoring passive interfaces before a clock source changes helps keep stable time signals on the 1588v2 network.
After the router stably synchronizes time signals with a clock source, the router can monitor the performance of its passive interface. The router checks the offset between the master and slave clocks on the passive interface every 300s. If the offset greater than a configured alarm threshold, the router sends an alarm named hwPtpPassiveFiberLengthChange to a network management system (NMS).
Perform the following step on each of BCs and TCandBCs: