AlwaysOn Data Connections for Portable Navigation Devices

10/16/2008

Applies to Windows Embedded NavReady

When an AlwaysOn connection is established, it remains always connected.

Overview of AlwaysOn Data Connections

The AlwaysOn feature helps guarantee that the Windows Embedded CE-based portable navigation device (PND) always maintains its packet-data connection after the application establishes a connection. To establish an AlwaysOn data connection, the connection must be configured as AlwaysOn. Following initial configuration, Connection Manager will try to keep the AlwaysOn data connection always connected.

You can designate any data connection as AlwaysOn; you typically do so for Suspend/Resume-capable connections. However, make sure that you do not make this designation for an active data connection because doing so could prevent the device from receiving incoming calls.

Retrying an AlwaysOn Data Connection

An AlwaysOn data connection might not connect because the device is out of range, the device is not available, or the device is in use by a higher-priority connection request. If activation fails in a recoverable way, such as any way except through an incorrect username, password, APN, or upon remote disconnect, and the device remains in either the home or roam registration state, Connection Manager uses the following retry logic.

• Retry one time immediately.

• Retry every 30 minutes until success. To change the periodic retry interval, modify the AlwaysOnRetryInterval value under the HKEY_LOCAL_MACHINE\Comm\ConMgr\Planner\Settings\AlwaysOnRetryInterval registry key, as shown in the following table.

  Name	Type	Value
  AlwaysOnRetryInterval	DWORD	Specifies the retry interval in milliseconds. The default value is 1800000, which specifies an interval of 30 minutes.

  Note

  A connection remains AlwaysOn only if it is configured as such. If the connection receives a disconnect event, it will be disconnected and the change of state will be communicated to the Connection Manager AlwaysOn manager. Connection Manager will then try to reestablish the connection as described earlier in this topic.

AlwaysOn as Default

ActiveSync Desktop Pass-through (DTPT) connections are set to AlwaysOn.

Note

You can modify the AlwaysOn setting for all connections except for DTPT connections, which are forced to be AlwaysOn.

AlwaysOn and the Idle State

If the Windows Embedded NavReady powered device (PND) goes into an idle or sleep state, the AlwaysOn feature helps guarantee that no active-packet data session is disconnected. Depending on your power-management implementation, the following list shows the events that might trigger a Windows Embedded CE powered device to go into an idle state:

• User presses the power button to turn off the device
• Idle time out occurs
• The OEM or software developer explicitly makes a system call to put the device into an idle state

In all cases in the previous list, any active-packet data connection would remain active in the idle state. Even when the device is in an idle state, it is reachable and immediately available without reconnection when the device transitions from the idle state.

See Also

Concepts

How to Make a Data Connection by Using Connection Manager

Other Resources

Connection Manager Application Development for Portable Navigation Devices