Using the delay parameter, frames are not reordered even if subjected to differing
delays. For example, if the delay is specified as a uniform distribution between 10 and
100 ms and the first frame is subjected to a 90 ms delay and the second frame is
subjected to a 20 ms delay, the second frame will not be transmitted until after the
first frame has been transmitted. This effect can skew the measured mean delay to be
higher than the configured value when using a normal or uniform distribution.
4.1.3 Loss
Data loss rates are configured as bit error rates, packet loss rates, or both. Losses due to packet
loss and bit errors are emulated independently and may be combined to emulate links with
physical layer corruption as well as congestion-induced packet loss.
For a lossless link, set the packet loss rate and bit error rate to 0. The default setting is for a
lossless link.
Packet loss rates can be set from 0 – 100% in increments of 0.0001%.
Bit error rates can take values of 1x10
-14
or greater and are entered in scientific notation. The
coefficient of the rate (the field on the left) must be entered as a value greater than or equal to 0
and less than 10. The exponent may be between -1 and -14. The minus sign is supplied and only
the digits of the exponent should be entered in the exponent field.
Losses are assumed to occur over the WAN link itself. Discarded packets therefore consume WAN
bandwidth. For example, if a 1 Mbps link is specified to have a 10% packet loss rate, the maximum
possible average throughput is 900 Kbps.
4.2 Advanced Parameters
To view and configure advanced emulation parameters, click on the
show
link next to the
Advanced Parameters label. Note that even when hidden, the advanced parameter settings are
used in the emulation. The advanced parameters section cannot be hidden when any of the
entered values are invalid.
S
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:
L
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ARAMETER
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ONFIGURATION
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