In normal case PTP in PHASE ALIGNED state & When i switch over from RE0 to RE1 in ACX7509 router, PTP 8275.1 is stuck in FREERUN state.

I checked the PTP statistics in router and found this don't have any packet send or received.

Initial in RE0:

juniper@JTAC-re0> show ptp lock-status detail | no-more

Lock Status:

Lock State : 5 (PHASE ALIGNED)

Phase offset : 0.000000000 sec

State since : 2025-06-11 09:36:55 +07 (23:56:58 ago)

Selected Master Details:

Upstream Master address : e4:5e:cc:ff:fe:bb:8f:24

Slave interface : ae11.1 (et-0/0/5, primary)

Clock reference state : Clock locked

1pps reference state : Clock qualified

{master}

juniper@JTAC-re0> show ptp hybrid status detail

Hybrid Mode Status:

Configured Mode : Hybrid

Operating Mode : Hybrid

PTP Reference : e4:5e:cc:ff:fe:bb:8f:24, ae11.1 (et-0/0/5, primary)

Synchronous Ethernet Reference : et-0/0/5

Lock state : Locked

Lock state description : Frequency Locked Phase Locked

After switcover to RE1

juniper@JTAC-re1> show ptp lock-status detail | no-more

Lock Status:

Lock State : 1 (FREERUN)

Phase offset : 0.000000000 sec

State since : 2025-06-12 09:37:14 +07 (00:03:44 ago)

{master}

juniper@JTAC-re1> show chassis synchronization extensive

Current clock status : Locked

SNMP trap status : Disabled

Configured sources:

Interface : et-0/0/5

Status : n/a Index : 1225

Clock source state : n/a Priority : Default(8)

Configured QL : SEC ESMC QL : PRC

Clock source type : ifd Clock Event : n/a

Wait-to-restore : 5 min Hold-off : 1000 ms

Interface State : Up,ESMC Rx(QL PRC/SSM 0x2),ESMC TX(QL DNU/SSM 0xf),

Ineligibility reason: Awaiting election of PTP remote master

juniper@JTAC-re1> show ptp statistics

Local Clock Remote Clock Role Stream Received Transmitted

ae11.1 01:1b:19:00:00:00 Slave 0 0 0

et-0/0/5

ae10.1 01:1b:19:00:00:00 Master 0 0 0

et-0/0/1

We are not supporting PTP for RE switchover (GRES or non-GRES), as of 4th July 2025.

Observations:

• ACX7509 PTP gets locked with RE0
• Upon switching over to RE1, all routing/traffic switches fine, except PTP & all ptp packet stats will be zero
• Once we switch over back to RE0, PTP will work again

We found the internal PR associated with the issue & it confirms the support for PTP on switchover is not available now.

And this is getting fixed via another internal PR, 1887396