Web Management Guide-R05

Table Of Contents
Chapter 13
| Basic Administration Protocols
Connectivity Fault Management
– 494
Figure 313: Transmitting Loopback Messages
Transmitting
Delay-Measure
Requests
Use the Administration > CFM (Transmit Delay Measure) page to send periodic
delay-measure requests to a specified MEP within a maintenance association.
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
function.
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.