Step 5
Enter the
config slot slot number channel ap ap-name channel number
command to assign a particular channel to the
1524 RAP downlink radio.
•
slot number
refers to the slot of the downlink radio to which the channel is assigned.
•
ap-name
refers to the name of the access point on which the channel is configured.
•
channel number
refers to the channel that is assigned to a slot on the access point.
Slot 2 of the 1524 RAP acts as a downlink radio. If backhaul channel deselection is enabled, you can assign only
those channels that are available in the DCA list the access point.
The following is a sample output:
(Controller) >
config slot 2 channel ap Controller-RAP2-1524 136
Mesh backhaul dca-channels is enabled. Choose a channel from the DCA list.
(Controller) >
config slot 2 channel ap Controller-RAP2-1524 140
Backhaul Channel Deselection Guidelines
Follow these guidelines when configuring backhaul channel deselection:
• Channels for serial backhaul RAP 11a access radio and both 11a radios of serial backhaul MAPs are
assigned automatically. You cannot configure these channels.
• Look out for trap logs on the controller. In case of radar detection and subsequent channel change,
messages similar to below appear:
Channel changed for Base Radio MAC: 00:1e:bd:19:7b:00 on 802.11a
radio. Old channel: 132. New Channel: 116. Why: Radar. Energy
before/after change: 0/0. Noise before/after change: 0/0.
Interference before/after change: 0/0.
Radar signals have been detected on channel 132 by 802.11a radio
with MAC: 00:1e:bd:19:7b:00 and slot 2
• For every serial backhaul AP, channels on downlink and uplink radios should always be noninterfering
(for example, if the uplink is channel 104, the 100, 104, and 108 channels cannot be assigned for a
downlink radio on that AP). An alternate adjacent channel is also selected for an 11a access radio on
RAP.
• If radar signals are detected on all channels except the uplink radio channel, the downlink radio will be
shut down and the uplink radio will act as both an uplink and a downlink (that is, the behavior is similar
to 1522 APs in this case).
• Radar detection is cleared after 30 minutes. Any radio that is shut down because of radar detection should
be back up and operational after this duration.
• There is a 60-second silent period immediately after moving to a DFS-enabled channel (irrespective of
whether the channel change is because of radar detection or user configured in case of a RAP) during
which the AP scans for radar signals without transmitting anything. A small period (60 seconds) of
downtime may occur because of radar detection, if the new channel is also DFS-enabled. If radar detection
occurs again on the new channel during the silent period, the parent changes its channel without informing
Cisco Mesh Access Points, Design and Deployment Guide, Release 7.3
146
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Connecting the Cisco 1500 Series Mesh Access Points to the Network
Backhaul Channel Deselection on Serial Backhaul Access Point