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Transmitting on-demand delay-measure requests, Figure 313 t, Transmitting on-demand delay-measure – Brocade 6910 Ethernet Access Switch Configuration Guide (Supporting R2.2.0.0) User Manual

Page 1077: Requests

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Brocade 6910 Ethernet Access Switch Configuration Guide

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Connectivity Fault Management

FIGURE 313

Transmitting Loopback Messages

Transmitting On-Demand Delay-Measure Requests

Use the Administration > CFM (Transmit Delay Measure) pages to send on-demand delay-measure
requests to a specified MEP within a maintenance association. Delay measurement can be used to
measure frame delay and frame delay variation between MEPs.

CLI References

“ethernet cfm delay-measure two-way”

on page 560

“ethernet cfm delay-measure one-way”

on page 559

Command Usage

Both the source and destination MEP must be configured for the same MA before transmitting
delay-measure messages.

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.

The MEP can also make frame delay variation measurements based on its ability to calculate
the difference between two subsequent two-way frame delay measurements.

Two-Way Delay Measure

If a MEP is enabled to generate frames with two-way delay measurement (DM) information, it
sends DM frames to a peer MEP in the same MA, and expects to receive DM frames back from
it.

When two-way frame delay measurement are made, the transmitting MEP sends 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)