This feature is supported only on the 7210 SAS-Sx 1/10GE and 7210 SAS-Sx 10/100GE.
The 7210 SAS devices support PTP end-to-end (E2E) Transparent Clock (TC) functionality, which allows the node to update the PTP correction fields (CFs) for the residence time of the PTP message. See Table: Synchronization options for 7210 SAS platforms for a list of platforms that support this functionality.
A CLI option is provided to enable the PTP port-based hardware timestamp on ports that receive and forward PTP messages. To enable the TC function, PTP must not be enabled on the node. When the timestamp option is enabled, the node identifies standards-based messages and updates the CF for PTP IP/UDP multicast and unicast messages, and for the PTP Ethernet multicast and unicast messages. The CF is updated for the residence time of the PTP message. Downstream PTP timeReceivers that receive the PTP message use the updated CF to measure the delay between the timeTransmitter and themselves.
You can enable the TC option by running the configure>port>ethernet>ptp-hw-timestamp command on ports (both ingress and egress) on which residence time in the PTP message must be updated when the message is in transit through the node. You can disable the residence time update by running the no form of the command on both ingress and egress ports, as required. No additional CLI commands are required to enable the PTP TC option.
Nokia recommends the following operational guidelines and examples for enabling and using the PTP TC feature:
Assume port 1/1/10 is connected to a PTP timeTransmitter clock (using a port, a SAP, or an IES IP interface) and 1/1/15 is connected to a PTP timeReceiver clock (using a port, a SAP, or an IES IP interface).
To enable PTP TC in this scenario, you must enable the ptp-hw-timestamp command on both ports. To disable PTP TC, run the no form of the command on both ports.
Assume port 1/1/10 is connected to a PTP timeTransmitter clock (using a port, a SAP, or an IES IP interface) and ports 1/1/15 and 1/1/16 have PTP timeReceivers (using a port, a SAP, or an IES IP interface), with a PTP session to the PTP timeTransmitter clock that is connected on port 1/1/10.
To enable PTP TC, the ptp-hw-timestamp command must be enabled on all three ports.
In this scenario, it is not possible to disable PTP TC only towards the timeReceiver connected on port 1/1/15. The functionality must be disabled on all three ports.
Additionally, note that the PTP messages coming in on port 1/1/10 are not forwarded out of any ports other than 1/1/15 and 1/1/16, when the ptp-hw-timestamp command is enabled on port 1/1/10. Nokia recommends that when a set of PTP ports are enabled for ptp-hw-timestamp, the operator must ensure that PTP messages are forwarded to only the specific set of ports where the TC option is enabled, and not to other ports. Forwarding PTP messages to other ports that do not belong to the specific set may result in incorrect updates.
You can enable PTP TC for a set of SAPs and also transparently forward PTP packets on other SAPs, while both SAPs share a common uplink to forward PTP messages. To implement this scenario, use MPLS tunnels with network ports as the uplinks. Nokia recommends the following configuration.
PTP hardware port-based timestamping must be disabled on the access ports where SAPs are configured. These access ports are typically used to connect to either PTP timeTransmitter or PTP timeReceivers that need to establish and exchange PTP messages transparently.
PTP hardware port-based timestamping must be enabled on the access ports where SAPs are configured and the TC function is required. These access ports are typically used to connect to either the PTP timeTransmitter or PTP timeReceivers.
PTP hardware port-based timestamping must be enabled on the network ports where the MPLS tunnels originate and terminate. In this case, the PTP TC function updates only the PTP messages that are not MPLS encapsulated.
See PTP message transparent forwarding for additional support information.