User Manual User guide

258 Rockwell Automation Publication 1783-UM006A-EN-P - May 2014
Chapter 7 Configuring Radio Settings
• If participating in WDS, sends a DFS notification of its new operating
frequency to the active WDS device.
This table lists the channels and the frequencies that require DFS.
For autonomous operation, DFS requires random channel selection among the
channels listed. The channels not listed don’t require random selection and can
be manually configured.
Channels requiring Dynamic Frequency Selection (DFS) can be manually
selected for the Stratix 5100 Wireless Access Point/Workgroup Bridge by using
the -E or -M regulatory domains. The same GUI/CLI you use to manually
configure non-DFS channels can be used to select DFS channels as well. The
default channel selection is DFS, that randomly selects a channel.
If radar is detected on a manually configured DFS channel, the channel changes
automatically and does not return to the configured channel.
Prior to transmitting on any channels listed in Table 84 on page 258
, the access
point radio performs a Channel Availability Check (CAC). The CAC is a 60
second scan for the presence of radar signals on the channel. The following
sample messages are displayed on the access point console showing the beginning
and end of the CAC scan:
*Mar 6 07:37:30.423: %DOT11-6-DFS_SCAN_START: DFS: Scanning
frequency 5500 MHz for 60 seconds
*Mar 6 07:37:30.385: %DOT11-6-DFS_SCAN_COMPLETE: DFS scan
complete on frequency 5500 MHz
When operating on any of the DFS channels listed in Table 84 on page 258, in
addition to performing the CAC, the access point constantly monitors the
channel for radar. If radar is detected, the access point stops forwarding data
packets within 200 ms and broadcasts five beacons that include an 802.11h
channel switch announcement, indicating the channel number that the access
point begins using. The following example message appears on the access point
console when radar is detected:
TIP
You cannot manually select a channel for DFS-enabled 5 GHz radios in some
regions, depending on the regulatory requirements. The access points
randomly selects a channel in that case.
Table 84 - Channels Requiring DFS
Channel MHz Channel MHz Channel MHz
52 5260 104 5500 124 5620
56 5280 108 5520 128 5640
60 5300 112 5560 132 5660
64 5320 116 5580 136 5680
100 5500 120 5600 140 5700