Textron Greenlee Communications DataScout 10G, Руководство пользователя

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Users Manual
DataScout 10G & 10Gx
33
Frame Loss
Frame loss is simply the rate or number of frames lost through the range of data rates
and frame sizes. Lost Frames are those which were successfully transmitted but were
never received.
Latency
Also known as Frame Delay (FD), the Latency test or one-way delay measures the
time required for a frame to travel from the originating device through the network to
the destination device. The measurement is performed at the Throughput rate (above).
In order to measure latency a test frame containing a time stamp is transmitted through
the network. The time stamp is then checked when the frame is received to determine
the delay. This test is most commonly performed with a loopback at the terminating
location (round-trip delay).
Jitter
Also known as Frame Delay Variation (FDV), jitter is the variance of Minimum and
Maximum inter-packet arrival time and is displayed in nanoseconds (ns). You must run
two tests at same frame size to measure Jitter and should be done at the maximum
frame rate as this is where the most variation (packet delay) will occur.
Back-to-Back
Also know as Burst testing, the back-to-back test measures the longest frame burst
that the circuit or device under test (DUT) can handle without any Frame loss. The
test set sends burst of frames with minimum inter-frame gaps to the DUT and counts
the number of frames forwarded by the DUT. For optimum measurement the trial
length should be at least two seconds long and the measurement repeated at least 50
times with the average of the results reported for each frame size.
Starting a RFC-2544 Test
To Start an RFC-2544 test, first press the
menu key and select a test mode Looped
(default) or End-to-End test. Do not have USB storage turned ON (default is off) as
your PC and test set will collide when trying to save PDFs. Looped test is testing
to/from a device in loopback. End-to-End is testing to another test set. Next tap on the
check mark to select the type of tests you which to run (Throughput/Frame loss, Laten-
cy, and Back-to-Back)