On Windows devices, you can initiate synchronization when connectivity changes.

When IP connectivity is gained or lost, the device sends a push notification to the Listener with the message _IP_CHANGED_. When the device finds a new optimum path to the MobiLink server, it sends a push notification to the Listener with the message _BEST_IP_CHANGED_. Using a message handler, you can detect these changes in connectivity and initiate an action.

Identifying any change in connectivity

The _IP_CHANGED_ message indicates that a change in IP connectivity has occurred. A change usually occurs when a device is within range of a WiFi network, when the user makes a RAS connection, or when the user puts the device in a cradle. You can reference the _IP_CHANGED_ message by running the Listener with the following syntax:

dblsn ... -l "message=_IP_CHANGED_;action='...'"

The following example demonstrates how to use the _IP_CHANGED_ message. The message handler filters the message, and sends it to the server. If the connection is lost, an error is generated.

dblsn -l "message=_IP_CHANGED_;
    action='
        SOCKET port=12345;
        sendText=IP changed: $adapters|$network_names;
        recvText=beeperAck;
        timeout=5';
    continue=yes;"

Identifying a change in the optimum path to a MobiLink server

The _BEST_IP_CHANGED_ message indicates that a change in the optimum path to the MobiLink server has occurred. You can reference this message when you run the Listener with the following syntax:

dblsn ... -x MobiLink-protocol-options -l "message=_BEST_IP_CHANGED_;action='...'"

When filtering the _BEST_IP_CHANGED_ message, the $best_ip action variable, which substitutes the local IP address that represents the best IP connection, can help you initiate useful actions. If there is no IP connection, $best_ip returns 0.0.0.0.

In the following example, the _BEST_IP_CHANGED_ message is used to initiate a synchronization when the best IP connection changes. If the connection is lost, an error is generated.

dblsn -x http(host=mlserver.company.com) 
   -v2 -m -i 3 -ot dblsn.log 
   -l "message=_BEST_IP_CHANGED_;
       action='
           START dbmlsync.exe -ra -c eng=remote;uid=DBA;pwd=sql -n test_pub'"

See also

• MobiLink Listener utilities
• Listener action commands for Windows
• Listener action variables for Windows