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DTUS065 rev A.7 – June 27, 2014
V.7.5
Advanced Roaming settings
In several situations the basic roaming settings are not sufficient.
For example, if the Wi-Fi client is embedded on a train, and a directional
antenna is fixed on the roof, a high signal level means that the AP will soon
be on the other (bad) side of the directional antenna soon, hence it is a good
time to roam to another AP farther ahead, with a lower reception level.
In this case when the AP is seen with a high signal level it is likely that the
client will lose the association in the next few seconds.
Configuration
At the end of scan process, the product chooses a candidate AP. The
candidate AP is the AP where you will roam if the roaming is requested.
Roaming won’t occur before the
Minimum roaming interval
has elapsed
since the last association. In areas where several APs are received with about
the same signal quality, this parameter helps avoid frequent roaming due to
slight signal variations.
Roaming won’t occur to an AP that was left recently before the
No-return
delay
has elapsed. This parameter helps enforce roaming to a sequential
succession of APs, even if signal bounces make a previous AP appear
temporarily as more desirable.
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
AP1
AP2
AP3
AP eliminated from candidate list
AP eliminated from candidate list
AP considered for roaming
Roaming requested
Maximum signal
level
Excessive signal
detection threshold
Minimum signal
level
Current AP leave
threshold
