JDS Uniphase IP Video Test Option HST-3000, User Manual

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Chapter 7 Automated RFC 2544 Testing
About the Throughput test
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HST-3000 Ethernet Testing User’s Guide
equal to the number of frames carrying an Acterna payload
received over a 5 second interval of time. If the maximum
bandwidth shows no frame losses, it proceeds to the Verifica-
tion phase. Otherwise, it proceeds to the Attempting Phase,
Bandwidth Reducing Stage.
Attempting Phase, Bandwidth Reducing Stage
If frames were lost in the last attempt, the bandwidth is
reduced by 50%, rounded to the nearest tenth, hundredth, or
thousandth percent specified as the Bandwidth Measurement
Accuracy. Traffic is then transmitted at the reduced bandwidth
for another 5 seconds. If frames are lost, this stage is
repeated. Otherwise, it proceeds to the Bandwidth Increasing
Stage.
Attempting Phase, Bandwidth Increasing Stage
If no frames were lost, the bandwidth is increased by 50%,
and traffic is transmitted. If no frames are lost, the Bandwidth
Increasing Stage is repeated (bandwidth is increased again by
50%). Otherwise, it returns to the Bandwidth Reducing Stage.
The Attempting Phase continues until either no frames are
lost, or the transmitted bandwidth reaches the lowest band-
width limit (specified as the Bandwidth Measurement Accu-
racy). If the lowest bandwidth limit is reached without
successfully receiving every transmitted frame, the test indi-
cates that each of the test results is unavailable.
If Throughput results are unavailable, Latency and Packet
Jitter results can not be derived; therefore, they will also be
unavailable.
Verifying Phase
After the test determines the maximum bandwidth at which no
frames are lost, it then transmits traffic at that bandwidth for
the Throughput Trial Duration. If frames are lost, the test
reduces the bandwidth by the Bandwidth Measurement Accu-
racy, and then retransmits traffic for the Throughput Trial
Duration.