H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 578)

49-3
Figure 49-2 Primary AC recovery
In the above figure, AC 1 is the primary AC with the connection priority of 7, and it establishes a
CAPWAP connection with the AP; AC 2 acts as the secondary AC. If AC 1 goes down, AC 2 takes over
to provide services to AP until AC 1 recovers. This means once the primary AC is reachable again, the
AP automatically establishes a connection with the primary AC. For priority configuration, refer to
Configuring connection priority .
1:1 fast backup
Fast link fault detection allows two ACs in 1:1 backup to detect the failure of each other in time. To
achieve this, WLAN dual link mechanism is used. When the active AC goes down, the standby AC can
quickly detect the faults and become the new active AC. This is implemented in milliseconds. Support
for the 1:1 fast backup feature depends on the device model.
1+N AC backup
1+N AC backup allows an AC to operate as a backup for multiple ACs. The active ACs independently
provide services for APs connecting to them, and the only one standby AC provides backup service for
the active ACs. If any active AC goes down, the APs connecting to it can detect the failure quickly and
make connections to the standby AC. As soon as the active AC recovers, the APs automatically
connect to the original active AC again. This ensures that the standby AC works as a dedicated backup
for the active ACs. 1+N AC backup delivers high reliability and saves network construction cost greatly.
Continuous Transmitting Mode
The continuous transmitting mode is used for test only. It is recommended to not use the function unless
necessary.
Channel Busy Test
The channel busy test is a tool to test how busy a channel is. It tests channels currently supported by
the district code one by one, and provides a busy rate for each channel. This avoids the situation that
some channels are heavily loaded and some are idle.
During a channel busy test, APs do not provide any WLAN services. All the connected clients are
disconnected and WLAN packets are discarded.