metrotek Bercut-MMT, Operation Manual

Page: 26 / 85

26 RFC 2544. Parameters Configuration
•
Enable this test — is a flag that turns data transmission delay mea-
surement on or off for equipment under testing (functional key F2 has
the same meaning).
•
Trials — quantity of delay measurements for each frame size config-
ured.
• Duration — time period of one measurement iteration for each frame
size selected in the general frame size configuration (not more than
1200 s).
• Use custom frame rate (fps) — a flag that allows to enter values
manually. For each of frame sizes used, rate value is entered in the
corresponding field (functional key F3 has the same meaning).
The
Configure field allows to configure rate for arbitrary frame size,
selected in the Frame
⇒
custom tab.
Note: if this test is selected, it is necessary to either select
Throughput test (in this case Latency values will be calculated for
determined throughput), or define desirable frames transmission
rate.
Frame transmission rate values (if configured manually)
should not exceed theoretical maximum throughput value for cur-
rent settings.
4.4.1 Theoretical Maximum Throughput Value
Theoretical maximum throughput value is calculated using minimal values
of the following parameters:
•
preamble = 8 bytes;
•
frame size = 64 bytes;
•
interframe interval = 12 bytes.
Theoretical value is calculated according to the following formula:
M ax.throughp.
=
(
P hysical rate
)
(
P reamble
+
F rame size
+
Interf r. interval
)
Maximum theoretical throughput values calculated using this formula are
presented in the table below. Values are for standard frame sizes and physical
interface rates allowed for testing purposes.
Table 4.1: Theoretical Throughput Values
Frame size, Maximum rate, frames/s
bytes 10 Mbit/s 100 Mbit/s 1000 Mbit/s
Bercut-MMT: Ethernet Networks Analysis