R0106-HP MSR Router Series Layer 2 - WAN Configuration Guide(V7)

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Configuring DDR
Overview
As shown in Figure 48, routers use dial-on-demand routing (DDR) for the following purposes:
• Setting up a dialup connection over PSTN/ISDN when communication needs arise.
• Tearing down the connection when the communication is complete.
Figure 48 DDR communication process
In addition to PSTN/ISDN, Ethernet and ATM use DDR to implement access control. For more information,
see "Configuring PPPoE" and "Configuring ATM."
Interfaces in DDR
DDR uses the following dialup interfaces:
• Physical interfaces—Include the following interfaces:
{ Asynchronous serial interfaces.
{ Synchronous/asynchronous serial interfaces operating in asynchronous mode.
{ AM interfaces.
{ AUX interfaces.
{ ISDN BRI interfaces.
{ ISDN PRI interfaces.
{ Cellular interfaces.
• Dialer interfaces—Logical interfaces on which DDR parameters are configured.
DDR implementations
DDR supports traditional DDR and bundle DDR.
Traditional DDR
You can configure traditional DDR by using the following methods: