metrotek ETS-1000, Руководство по эксплуатации

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72 Analysis. Typical tasks and solutions
5.16 Packet jitter
Another important task for Ethernet-network testing is the packet jitter
measurements. According to the RFC 4689 methodology [6], the packet jitter
is the absolute value of the difference between the forwarding delay of two
consecutive received packets belonging to the same stream. This parameter
is used to estimate transmission capability of latency-sensitive traffic such as
video and speech data.
Packet jitter measurement is an optional
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feature.
Figure 5.83. Packet jitter. Summary
• ET — time elapsed since the test started.
• RT — time remained to the test finish.
•
PKTs — summary number of received packets.
•
OOOPs — number of received out-of-order packets.
•
%OOOPs — quantity of received out-of-order packets (percentage of
PKTs).
•
INOPs — number of packets received in the same order they were trans-
mitted.
•
%INOPs — quantity of packets received in the same order they were
transmitted (percentage of PKTs).
•
< ms
%
P KT s
— number of packets (percentage of PKTs) with jitter
value which is less then specified threshold.
•
>
=
ms
%
P KT s
— number of packets (percentage of PKTs) with jitter
value exceeding or equal to the specified threshold.
• Setup — switch to the Packet jitter. Setup menu .
By pressing the button ( Start ), the measurement of packet jitter for
the port which has been specified in the Packet jitter. Setup menu, is started.
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The feature is not included into basic configuration and should be purchased additionally.
ETS-1000. Operations manual