The access router is connected to the core router in the following way:

access router (et-1/1/2, MPC7E) ----- (et-19/1/1, MPC6E) core router

The access router is supposed to receive PTP synchronization from the core router, however the access router remained in Freerun state. The Freerun state indicates that there are no PTP packets received. Due to the described issue there were no PTP packets exiting the core router so the access router remained in Freerun state.

The issue was due to internal switch interface down condition on the FPC of the core router so the packets from PTP FPGA could not be transferred via the interface towards the access router. The internal switch ports state can be checked using the following command:

MPC19(router-re0 vty)# show mesw ports
GE-Port   | Link  | Speed | Auto-Neg | Port-map
-------------------------------------------------
0-0        UP       1000      Disabled     XM2-0
0-1        DOWN     1000      Disabled     XM2-1
0-2        DOWN     1000      Disabled     XM3-0      <<<<<<<<
0-3        DOWN     1000      Disabled     XM3-1
0-4        UP       1000      Disabled     XM0-0
0-5        DOWN     1000      Disabled     XM0-1
0-6        UP       1000      Disabled     XM1-0
0-7        DOWN     1000      Disabled     XM1-1
0-8        UP       1000      Disabled     CB0
0-9        UP       1000      Disabled     CB1
0-10       UP       1000      Disabled     PTP-1588
0-11       UP       1000      Disabled     MIC0
0-12       UP       1000      Disabled     MIC1
0-13       UP       1000      Disabled     TSEC-1
0-14       UP       1000      Disabled     TSEC-3
0-15       DOWN     1000      Disabled     N/C

The port on which PTP packets are supposed to reach the access router is et-19/1/1. In MPC6E XM3 is responsible for the port et-19/1/1 so the port 0-2 should be UP if the interface et-19/1/1 is in UP state.

The issue is due to hardware failure, the card on the core router was changed.