How Channels Are Selected; Channel And Power Tuning; Power Tuning; Channel Tuning - Nortel 2360 Configuration Manual

322 Configuring Auto-RF
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Initial power assignment—The AP sets a radio's initial power level to the maximum value allowed
for the country code (regulatory domain). In a deployment with few APs, the radio remains at
maximum power. Otherwise, the radio reduces power until the power is just enough to reach the
AP's nearest neighbor that is on the same channel.

How channels are selected

When a radio first comes up, if Auto-RF for channels is enabled, the initial channel selected will follow a uniform distri-
bution of channels that spans the list of channels, rather than selecting the next sequential channel number.
For example, the range of valid channels for 802.11a radios in the US is as follows:
40, 44, 48, 52, 56, 60, 64, and 68
On each WSS, the first channel chosen will be random. Assuming that channel 60 is the first channel selected, the order
of the channel selections will be as follows:
Order:
Channel:
After these initial 8 channel selections are chosen, the pattern will repeat itself.

Channel and power tuning

Auto-RF can change the channel or power of a radio, to compensate for RF changes such as interference, or to maintain
at least the minimum data transmit rate for associated clients. A radio continues to scan on its active data channel and on
other channels and reports the results to its WSS.
Periodically, the switch examines these results to determine whether the channel or the power needs to be changed.

Power tuning

By default, the switch evaluates the scan results for possible power changes every 300 seconds (5 minutes), and raises or
lowers the power level if needed.
If Auto-RF determines that a power change is needed on a radio, WSS Software ramps the power up or down until the
new power level is reached. Ramp-up or ramp-down of the power occurs in 1 dBm increments, at regular time intervals.
The default interval is 60 seconds and is configurable. The power ramp amount (1 dBm per interval) is not configurable.

Channel tuning

By default, the switch evaluates the scan results for possible channel changes every 3600 seconds (1 hour). WSS
Software uses the following parameters to determine whether to change the channel on a radio:
• Presence of active sessions.
By default, if the radio has active sessions, WSS Software does not change the channel. If the radio does
not have any active sessions, WSS Software uses the remaining parameters to determine whether to
change the channel.
• Received signal strength indication (RSSI)
NN47250-500 (320657-F Version 02.01)
2 5 8 3
40 44 48 52
6 1 4 7
56 60 64 68