Environment : This article applies to all RAP models and OS versions.
When we configure the 3G uplink for a RAP, we specify the link priority as well. The priority value determines the primary and backup link. By default, the Ethernet link has the higher priority. The link with the highest priority value becomes the primary. If the priority values of the Ethernet and 3G uplinks are the same, the Ethernet link has the higher priority.
When the primary link is down, the RAP automatically switches to the backup link. The primary link is considered to be down if the link is physically disconnected or if the controller is unreachable due to connectivity issues in the intermediate WAN. If the physical link is down, the RAP immediately switches to the backup link. However, if the controller is unreachable due WAN issues, the RAP attempts twice to reconnect to the controller using the primary link before it switches to the backup link. Even after the RAP successfully establishes a connection to the controller through the backup link, it periodically (every 170 seconds) checks the status of the primary link. If the primary link is up, the RAP
automatically tears down the backup link and establishes the IPsec connection to the controller through the primary uplink.