Configuration example for using ADSL to provide backup connections
Network requirements
As shown in Figure 15, Router is connected to Network Center through a DDN dedicated line and an ADSL connection, where the ADSL connection provides backup for the DDN dedicated line. When the DDN dedicated line fails, the Router initiates a PPPoE call to establish an ADSL connection to the Network Center on the demand of data transmitting. The ADSL connection is terminated when it idled for 2 minutes.
Figure 15: Network diagram
![](images/image13.png)
Configuring the router
# Configure a dialer interface.
<Router> system-view [Router] dialer-rule 1 ip permit [Router] interface dialer 1 [Router-Dialer1] dialer user user1 [Router-Dialer1] dialer-group 1 [Router-Dialer1] dialer bundle 1 [Router-Dialer1] ip address ppp-negotiate
# Configure a PPPoE session.
[Router-Dialer1] interface ethernet 1/1 [Router-Ethernet1/1] pppoe-client dial-bundle-number 1 idle-timeout 120 [Router-Ethernet1/1] quit
# Configure the DDN interface Serial 2/0.
[Router] interface serial 2/0 [Router-Serial2/0] ip address 10.1.1.1 255.255.255.0 [Router-Serial2/0] standby interface dialer 1 [Router-Serial2/0] quit
# Configure the static routes to the peer.
[Router] ip route-static 0.0.0.0 0 serial 2/0 preference 60 [Router] ip route-static 0.0.0.0 0 dialer 1 preference 70