Higher wireless network availability can be achieved by installing a standby
AP as a backup for a primary device and configuring it for hot standby
. When installed
on the same Ethernet LAN and configured consistently as a primary device, the
standby device associates to the primary device as a client and monitors the
primary device with periodic link test request packets sent over both the
Ethernet and wireless interfaces. The standby device assumes the role of AP by
activating its Ethernet port and accepting radio client associations if the
primary device fails to respond with a link test response packet.
Clients associated to the standby AP lose their connection during the hot
standby setup process. Enabling hot standby designates a device as a backup for
another AP. The standby device is placed near the AP it monitors, configured
exactly the same as the monitored device. The standby device queries the
monitored AP regularly through both the Ethernet and the radio. If the
monitored device fails to respond, the standby AP comes online and takes the
place of the monitored device in the network.
When hot standby is
enabled on the Services > Hot Standby page, a Standby Status field
displays. This field displays the current status of the hot standby and is
updated by clicking Refresh.
When setting up the standby AP, the MAC
address of the AP that the standby unit will monitor must be entered as well as
optional settings
. Record
the MAC address of the monitored AP before configuring the standby AP. The
standby AP also must duplicate several key settings on the monitored AP. These
settings are:
- Primary SSID (as well as additional SSIDs configured on the monitored AP)
- Default IP Subnet Mask
- Default Gateway
- Data rates
- WEP settings
- Authentication Types
On the monitored AP, set the role in radio network to Access Point Root
(Fallback to Radio Shutdown). This radio role prevents client devices from
remaining associated to the monitored AP if it loses its connection to the
wired LAN. If the monitored AP malfunctions, it shuts down its radio and
associated client devices roam immediately to the standby AP.
Hot
standby is more complex using the CLI. The configuration steps are shown in
Figures
,
.