Restrictions and Limitations for PTP
-
Precision Time Protocol (PTP) is supported only on the first 16 downlink ports and on all the uplink ports of the C9300-48UXM switch model.
-
The output of the show clock command on the device and PTP servo clock displayed in the output of the show platform software fed switch active ptp domain command are not synchronized. These are two different clocks used on the switch.
-
Inter-VLAN is not supported in PTP Transparent Clock Mode.
-
PTP is not supported on stacked devices.
-
The switch supports IEEE 802.1AS and IEEE 1588 Default profile and they are both mutually exclusive. Only one profile can be enabled on the switch at a time.
-
The Cisco PTP implementation supports only the two-step clock and not the one-step clock. If the switch receives a one-step message from the Grand Master Clock, the message will be dropped.
-
We do not recommend having non-PTP enabled devices in the PTP network since it decreases clock synchronization accuracy.
-
Signaling messages are not supported in Cisco IOS XE Gibraltar 16.12.1. These messages are dropped in the switch without being processed.
-
Management messages with broadcast target id will be forwarded with a reduced hop count when the boundary clock mode is enabled. Management messages will be forwarded without decreasing the boundary hop count when transparent clock mode is enabled.
-
Moving directly from one PTP mode to the other is not recommended. Clear the existing mode using no PTP mode and then configure a new mode.
-
IPv6 and VRF do not support PTP.
-
Transparent clock mode is not supported on native Layer 3 ports and EtherChannel interfaces. (boundary clock mode is supported on native Layer 3 ports)
-
You cannot configure PTP on any port of a supervisor module.
-
Stateful Switchover (SSO) does not support PTP. The PTP protocol restarts after a switchover.
-
MACsec with Precision Time Protocol (PTP) is not supported.