The ptp-hw-timestamp command is supported only on the 7210 SAS-Dxp 12p ETR, 7210 SAS-Dxp 16p, 7210 SAS-Dxp 24p, 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T, and 7210 SAS-K 3SFP+ 8C. On bootup, port-based hardware timestamping is enabled by default on all ports on the 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T, and 7210 SAS-K 3SFP+ 8C. It is disabled by default on the 7210 SAS-Dxp 12p ETR, 7210 SAS-Dxp 16p, and 7210 SAS-Dxp 24p. The correction field in the PTP IP/UDP messages and PTP Ethernet messages that are not addressed to the node are updated for the residence time of the packet in the node.
The ptp-hw-timestamp command must be enabled for the node to process locally-destined PTP packets.
Use the ptp-hw-timestamp command to disable port-based hardware timestamping on ports that transparently forward received PTP packets. See the 7210 SAS-D, Dxp, K 2F1C2T, K 2F6C4T, K 3SFP+ 8C Interface Configuration Guide for more information about the ptp-hw-timestamp command.
When PTP port-based hardware timestamping is disabled, the node does not update the correction field in PTP messages.
For example, to transparently forward PTP packets over MPLS tunnels that use access ports with SAPs to connect the PTP timeTransmitters or timeReceivers, you can use the ptp-hw-timestamp command to disable PTP port-based hardware timestamping on the access ports.
The configuration of port-based hardware timestamping on selective ports of the 7210 SAS-Dxp 12p ETR, 7210 SAS-Dxp 16p, 7210 SAS-Dxp 24p, 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T, and 7210 SAS-K 3SFP+ 8C platforms can be used for transparent PTP packet forwarding if PTP is enabled and used to time the node (that is, PTP messages are originated and terminated by the node acting as a PTP OC-timeReceiver or BC).
The following guidelines must be considered for transparent PTP packet forwarding:
To enable transparent PTP packet forwarding, use the configure>port>no ptp-hw-timestamp command to disable the feature on all ports that receive and forward IP-UDP and Ethernet PTP messages.
To enable transparent forwarding of PTP packets over MPLS tunnels on the 7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C, PTP hardware port-based timestamping must be disabled on the access ports where SAPs are configured. These access ports connect to either PTP timeTransmitter or PTP timeReceivers that need to establish PTP sessions and exchange PTP messages transparently. Disabling PTP hardware port-based timestamping is not required on network ports where the MPLS tunnels originate and terminate. As a result, these network ports can be used for PTP packet exchange when the node is a PTP boundary clock or an ordinary clock timeReceiver. If the requirement is to forward PTP packets transparently when MPLS uplinks are not used or when a hybrid port with a SAP is used, PTP hardware port-based timestamping must be disabled on the access port and hybrid port.