Edge-Core ECS4120-28F, Справочное руководство, Страница: 813 / 938

Chapter 26
| CFM Commands
Delay Measure Operations
– 813 –
Command Usage
◆
Delay measurement can be used to measure frame delay and frame delay
variation between MEPs.
◆
A local MEP must be configured for the same MA before you can use this
command.
◆
If a MEP is enabled to generate frames with delay measurement (DM)
information, it periodically sends DM frames to its peer MEP in the same MA.,
and expects to receive DM frames back from it.
◆
Frame delay measurement can be made only for two-way measurements,
where the MEP transmits a frame with DM request information with the
TxTimeStampf (Timestamp at the time of sending a frame with DM request
information), and the receiving MEP responds with a frame with DM reply
information with TxTimeStampf copied from the DM request information,
RxTimeStampf (Timestamp at the time of receiving a frame with DM request
information), and TxTimeStampb (Timestamp at the time of transmitting a
frame with DM reply information):
Frame Delay=(RxTimeStampb-TxTimeStampf )-(TxTimeStampb-RxTimeStampf )
◆
The MEP can also make two-way frame delay variation measurements based on
its ability to calculate the difference between two subsequent two-way frame
delay measurements.
Example
This example sends periodic delay-measure requests to a remote MEP.
Console#ethernet cfm delay-measure two-way dest-mep 1 md voip ma rd
Type ESC to abort.
Sending 5 Ethernet CFM delay measurement message, timeout is 5 sec.
Sequence Delay Time (ms.) Delay Variation (ms.)
-------- ---------------- ---------------------
1 < 10 0
2 < 10 0
3 < 10 0
4 40 40
5 < 10 40
Success rate is 100% (5/5), delay time min/avg/max=0/8/40 ms.
Average frame delay variation is 16 ms.
Console#