Timestamps for different Y.1731 messages are obtained as follows:
The 7210 SAS-D support is as follows:
Y.1731 2-DM messages for Down MEPs uses hardware timestamps for both Rx (packets received by the node) and Tx (packets sent out of the node). The timestamps is obtained from a free-running hardware clock. It provides accurate 2-way delay measurements and it is not recommended to use for computing 1-way delay.
Y.1731 2-DM messages for Up MEPs, 1-DM for both Down MEPs and UP MEPs, and 2-SLM for both Down MEPs and Up MEPs use software based timestamps on Tx and hardware based timestamp on Rx. It uses the system clock (free-running or synchronized to NTP) to obtain the timestamps.
For the 7210 SAS-Dxp, Y.1731 2-DM and 1-DM messages for both Down MEPs and Up MEPs use software-based timestamps on Tx and hardware-based timestamps on Rx. Timestamps are obtained from the system clock, which is free-running or synchronized to NTP.
The 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T, and 7210 SAS-K 3SFP+ 8C support hardware time-stamping for Y.1731 1-DM, 2-DM and SLM. The timestamp values are obtained using a synchronized clock. The synchronized clock provides timestamp values as follows:
When neither PTP nor NTP is enabled in the system, the synchronized clock is same as free-run system clock. Therefore, accurate two-way delay measurements are possible. However, one-way delay measurements can result in unexpected values.
When NTP is enabled in the system, the synchronized clock is derived by the NTP clock.
When PTP is enabled in the system, the synchronized clock is derived by PTP clock.
Accurate results for one-way and two-way delay measurement tests using Y.1731 messages are obtained if the nodes are capable of time stamping packets in hardware.