Dial-on-demand Routing
Dial on Demand Routing (DDR) is a routing technique where a network connection to a remote site is established only when needed. In other words, if the router tries to send out data and the connection is off, then the router will automatically establish a connection, send the information, and close the connection when no more data needs to be sent. DDR is advantageous for companies that must pay per minute for a WAN setup, where a connection is always established. Constant connections can become needlessly expensive if the company does not require a constant internet connection.
Read more about Dial-on-demand Routing: How It Works, Design Considerations, Why DDR Is Still Used Today, Defining Connection Access, Dialer Maps and Rotary Groups