EXFO ETS-1000 - Manual (Page 44)

Typical Tasks and Solutions
36 ETS-1000
RFC 2544 Methodology
Frame Loss Rate
This test allows to estimate network’s ability to support real-time operating
applications because the big loss percentage will result in service quality
degrading.
Frame loss test allows to count the percentage of frames that have not
been transmitted by DUT due to lack of hardware resources.
To test the frame loss rate, a specific number of frames (input count) is
sent at a specific rate through the DUT to be tested and then the analyzer
counts the frames that are transmitted by the DUT (output count). The
frame loss rate at each point is calculated using the following equation:
100 × (input count - output count) / (input count)
The first trial should be run for the frame rate that corresponds to 100% of
the maximum rate for the frame size on the input media. Repeat the
procedure for the rate that corresponds to 90% of the maximum rate used
and then for 80% of this rate. The trials are continued with 10% reducing
intervals (a finer granularity is supported) until there are two successive
trials in which no frames are lost.