DDR implementations

DDR includes traditional DDR and bundle DDR. The device supports only bundle DDR in the current software version.

You can configure traditional DDR by using the following methods:

• Configure DDR parameters directly on a physical interface.

  The router places or receives calls through the physical interface.

  The physical interface can have one or more call destinations.

  This method applies when only one interface places or receives calls.

• Configure DDR parameters on a dialer interface.

  A dialer interface is associated with a group of physical interfaces and selects a physical interface to place or receive calls.

  A dialer interface can have one or more call destinations. A dialer interface with multiple call destinations can use any associated physical interface to place calls to any of the call destinations.

  A physical interface can belong to only one dialer interface.

  This method applies when one or more interfaces place or receive calls.

When using bundle DDR, you can configure DDR parameters only on a dialer interface.

A dialer interface corresponds to a dialer bundle. A dialer bundle can contain multiple physical interfaces. You can assign a priority to each physical interface in the dialer bundle. Each time a call is placed, the highest-priority physical interface available is selected. If multiple physical interfaces with the highest priority are available, these interfaces are selected in a round-robin manner.

A dialer interface can have only one call destination.

A physical interface can belong to multiple dialer bundles and can be used by multiple dialer interfaces at different times.

Traditional DDR is based on one-to-one bindings between dial services and physical interfaces. A new dial service requires a new physical interface. As a result, traditional DDR has poor extensibility.

	NOTE: A dial rule (configured by using the dialer-group rule command) defines one dial service.

Bundle DDR is simpler and more flexible than traditional DDR. Bundle DDR separates physical interface configuration and logical configuration for calls and allows one-to-many bindings between dial services and physical interfaces. A physical interface can serve multiple dial services.