ISDN

Configuring Dial Backup with Dialer Profiles

Configure a Dialer Interface

To configure the dialer interface that will be used as an intermediary between a physical interface that will function as backup interface and the interfaces that will use the backup, use the following commands beginning in global configuration mode:

Step	Command	Purpose
1	interface dialer number	Create a dialer interface.
2	ip unnumbered loopback0	Specify IP unnumbered loopback.
3	encapsulation ppp	Specify PPP encapsulation.
4	dialer remote-name username	Specify the remote router's CHAP authentication name.
5	dialer string dial-string	Specify the remote destination to call.
6	dialer pool number	Specify the dialing pool to use for calls to this destination.
7	dialer-group group-number	Assign the dialer interface to a dialer group.

Configure a Physical Interface to Function as Backup

To configure the physical interface that is to function as backup, use the following commands beginning in global configuration mode:

Step	Command	Purpose
1	interface type number	Specify the interface.
2	encapsulation ppp	Specify PPP encapsulation.
3	dialer pool-member number	Make the interface a member of the dialing pool that the dialer interface will use; make sure the number arguments have the same value.
4	ppp authentication chap	Specify CHAP authentication.

Configure Interfaces to Use a Backup Interface

To configure one or more interfaces to use a backup interface, use the following commands beginning in global configuration mode:

Step	Command	Purpose
1	interface type number	Specify the interface to be backed up.
2	ip unnumbered loopback0	Specify IP unnumbered loopback.
3	backup interface dialer number	Specify the backup interface.
4	backup delay enable-delay disable-delay	Specify delay between the physical interface going down and the backup being enabled, and between the physical interface coming back up and the backup being disabled.

 

Dialer Profile for ISDN BRI Backing Up Two Leased Lines Example

The following example shows the configuration of a site that backs up two leased lines using one BRI. Two dialer interfaces are defined. Each serial (leased line) interface is configured to use one of the dialer interfaces as a backup. Both of the dialer interfaces use dialer pool 1, which has physical interface BRI 0 as a member. Thus, physical interface BRI 0 can back up two different serial interfaces and can make calls to two different sites.

interface dialer0

 ip unnumbered loopback0

 encapsulation ppp

 dialer remote-name Remote0

 dialer pool 1

 dialer string 5551212

 dialer-group 1

interface dialer1

 ip unnumbered loopback0

 encapsulation ppp

 dialer remote-name Remote1

 dialer pool 1

 dialer string 5551234

 dialer-group 1

interface bri 0

 encapsulation PPP

 dialer pool-member 1

 ppp authentication chap

interface serial 0

 ip unnumbered loopback0

 backup interface dialer 0

 backup delay 5 10

interface serial 1

 ip unnumbered loopback0

 backup interface dialer1

 backup delay 5 10

Ref:

http://www.cisco.com/en/US/docs/ios/12_0/dial/configuration/guide/dcdbakdp.html