The settings for connectivity check may be adjusted on the “ADVANCED” tab of the BBNA Management Interface. These settings determine how the BBNA discovers and monitors connectivity of the individual WAN interfaces.

The BBNA attempts to reach external servers to determine if a WAN interface is successfully connected. The connectivity check proceeds in three phases: resolving connectivity check addresses, pinging connectivity check addresses, and simultaneously pinging and attempting HTTP connections to connectivity check addresses. The maximum number of seconds to spend during each phase may be adjusted by clicking on “settings” in the “Index” column of the “Connectivity Check Settings” configuration table. If desired, to immediately check HTTP in addition to ICMP the time for the ping phase may be reduced to zero. Be aware, though, of the bandwidth overhead of retrieving HTTP responses on very limited lines. If you want to disable HTTP connectivity check, you can set ‘Mixed Phase Time’ to 0. Also in some case we have seen the upstream modems/router intercepting the HTTP requests and responding back, which will incorrectly report the line is connected, hence setting ‘Mixed Phase Time’ to 0 would get rid of those issues. The device in that case will only use ICMP to probe external sites such as google’s dns (8.8.8.8), msn, anycast IP, etc.

The BBNA internally manages a list of active server IPs that are used for these checks, which are automatically updated as long as the BBNA maintains a connection to the Internet. Additional servers may be added manually by clicking the “Add” button next to “Additional Remote Servers for Connectivity Check” on the “ADVANCED” tab and entering the server’s IP. These servers should be responsive to ICMP and/or HTTP requests and be available with high reliability.