Customer Service Center

Symptoms The Spirent ports don’t reach the right PTP state and stay on listening. On DUT side the PTP counters show no PTP messages received from Spirent. Environment Spirent TestCenter IEEE-1588v2 PTP Explanation/Resolution It could be Spirent TestCenter was configured with all 1588 PTP devices using the same clock identity. This was confusing the devices since they were receiving clocks from a master that had the same clock identity. To reconfigure, simply highlighted all the devices and do a fill increment on the Clock Identity so that all devices are now different. Then the devices can distinguish between himself and the master clock. It could also be the 1588 PTP devices are configured on a different domain. Set the appropriate domain in DUT or TestCenter so that they are matching. There is a domain column on the TestCenter 1588v2 configuration. You can capture the 1588v2 messages and check the domain number (in wireshark it shows as the subdomainnumber). When set to Slave-Only mode, the priority must be higher than Master. If priority on Slave in Slave-Only mode is lower than the Master it will stay in listening state. Actually it is the expected behavior. The behavior is specified in section ‘9.2 State protocol’ of IEEE1588v2 2008 spec. A slave-only clock can never enter the MASTER state. However if the State Decision or BMCA recommends the state of Slave-Only node to be a Master, it shall remain in Listening state. Meaning the node marked as Slave-only remains in Listening state it’s clock attributes are better than the node connected to it.  Please check the below state diagram for the state transitions in Slave-only mode.  This behavior is in accordance with the below state diagram.  Root Cause Configuration issue on Spirent side.