Limitations of PTP

The following are the limitations of the implementation of PTP:

• Layer 2 transport is not supported.
• IPv6-UDP transport is not supported.
• Multicast event messages are not supported.
• Peer-to-peer delay mechanism is not supported.
• PTP datasets are not maintained for end-to-end transparent clocks.
• Domain number cannot be assigned to end-to-end transparent clocks.
• Boundary clock does not support synchronizing clocks across multiple domains.
• Distributing clock frequency recovered from SyncE or from BITS or from a TDM port over PTP is not supported.
• Ordinary clock master (Grandmaster) mode is not supported.
• Synchronizing system time with the time recovered from PTP event messages is not supported.
• Time of Day (ToD) output and inputs are not supported.
• Unicast message negotiation on clock ports is not supported.
• PTP cannot be used if network clock source is configured as BITS.

The following limitation also apply to 7520 and 7720 series switches:

• Stacking with PTP is not supported.
• PTP transparent clock is not supported.