Restrictions and Limitations for Precision Time Protocol
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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.
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Precision Time Protocol (PTP) is supported only on the first 36 downlink ports and on all the uplink ports of the C9300-48UN switch model.
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Synchronization of PTP clock from system clock and vice versa is not supported.
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Inter-VLAN is not supported in PTP Transparent Clock Mode.
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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.
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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.
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We do not recommend having non-PTP enabled devices in the PTP network since it decreases clock synchronization accuracy.
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Signaling messages are not supported in Cisco IOS XE Gibraltar 16.12.1. These messages are dropped in the switch without being processed.
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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.
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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.
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IPv6 and VRF do not support PTP.
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Transparent clock mode is not supported on native Layer 3 ports and EtherChannel interfaces. (boundary clock mode is supported on native Layer 3 ports)
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Stacking all 8 stack members may reduce performance or result in differences in mean delay and clock offset values.
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The C9300-48HX, C9300-48TX, C9300-24HX, C9300X-48HXN, C9300-24UX, C9300-48UXM, C9300-24UXB, and C9300-48UN switch models do not support gPTP at 100Mbps speed.
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PTP is not supported on Cisco StackWise Virtual configured devices.