EXFO ETS-1000G - Manual (Page 30)

RFC 2544
20 ETS-1000G
Latency Analysis
Latency Analysis
Note: An analysis of latency is used for evaluating the time it takes a frame to be
transferred from the source to the destination and back to the source
element. A variable latency value may cause problems in the operation of
real-time services.
During an analysis of latency, the throughput of DUT is determined first.
Then a frame ow is sent to the destination for each packet size determined
by RFC 2544 at the flow data rate corresponding to it. After a while a label
of the specific format is inserted into one packet. A Ta value (the time by
which the labeled packet has been completely transmitted) is recorded on
the transmitting side. On the receiving side the label is identified and a Tb
value (the time when the labeled packet was received) is recorded.
A latency is a difference (Tb - Ta). The analysis results are used for
calculating an average latency.