dial on demand routing (DDR)

Dial on DemandRouting (DDR) is a routing method in wide area networks, whereby a dial-up connection is only established when user data has to be transmitted. In order to reduce transmission costs, the connection is then terminated if no user data is pending for transmission within a predefined time interval. A prerequisite for this technique is that the router supports spoofing methods such as the Address Resolution Protocol ( ARP).