EXFO FTB-1, User Manual

Page: 225 / 675

Test Setup - Test Configurator, Timer, and System
NetBlazer
213
RFC 2544 - Subtests
Latency Configuration
The objective of the test is to measure the time required for the frame to go
through the device under test and return back to source. Starting by
sending a stream of frames for the predefined duration
(Trial Duration)
and throughput (
Max. Rate
) at a particular frame size, an identifying
dependent tag is included in one frame. The time at which this frame is
transmitted is recorded (
timestamp A
). When the tagged frame comes
back, the time is recorded again ( timestamp B ) and the Latency result is:
timestamp B - timestamp A
. The test is repeated for the defined number
of times ( Trials ) and the average result is calculated. The test is performed
for each defined frame size.

Trial Duration represents the time value for each trial in
“minutes:seconds”:
1
second (default) to
2
minutes.

Trials represents the number of times the test will be generated:
1
(default) to
50
trials.

Copy From Throughput check box, when selected (default), uses the
Throughput subtest results max rate value for each corresponding
frame size. When the check box is cleared, it is possible to set the
Max. Rate
by tapping on the
Config. per Frame Size
button.

Margin % , available when Copy From Throughput check box is
selected, decreases the max rate value(s) from the Throughput subtest
by a value corresponding to the percentage of the line rate specified:
0
(default) to
10
percent.