7210 SAS-MXP, R6, R12, S, SX, T BASIC SYSTEM
CONFIGURATION GUIDE RELEASE 22.9.R1
System management
The following figure shows the logical model for using PTP/1588 for network synchronization.
Figure 27: Logical model for using PTP/1588 for network synchronization on 7210 SAS platforms
6.5.7.2 Performance considerations
Although IEEE 1588v2 can be used on a network that is not PTP-aware, the use of PTP-aware network
elements (boundary clocks) within the packet switched network improves synchronization performance
by reducing the impact of PDV between the grandmaster clock and the timeReceiver clock. In particular,
when IEEE 1588v2 is used to distribute high-accuracy time, such as for mobile base station phase
requirements, the network architecture requires the deployment of PTP awareness in every device
between the grandmaster and the mobile base station timeReceiver.
In addition, performance is also improved by the removal of any PDV caused by internal queuing within the
boundary clock or timeReceiver clock. This is accomplished with hardware that is capable of port-based
timestamping, which detects and timestamps the IEEE 1588v2 packets at the Ethernet interface.
6.5.7.3 PTP end-to-end Transparent Clock
Note:
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
30: 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:
3HE 18197 AAAB TQZZA
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