6.2 Dialer Profile
6.2.8 Configuration example: Using dialer profiles to enhance DDR

In this configuration example, the central-site router has a PRI connection and internal modems. The router is configured to receive both async and BRI calls. The incoming async calls are sent to the internal modems. A dialer interface has been configured to receive ISDN BRI calls from the branch office. The following steps describe the commands used to configure the central-site router.

Step 1

  • Under the PRI D channel, the following command will have analog calls sent to the internal modem:
    CentralA(config-if)#isdn incoming-voice modem
  • The following links this serial interface to the dialer pool:
    CentralA(config-if)#dialer pool-member 1

Step 2

  • To configure an asynchronous group:
    CentralA(config)#interface group-async 1

The following list shows the commands for the Step Two configuration requirements:

  • To have async lines 65 to 70 service this interface:
    CentralA(config-if)#group-range 65 70
  • To make the interface not have its own IP address, and instead borrow the interface E0 address:
    CentralA(config-if)#ip unnumbered e 0/0
  • To have the encapsulation be PPP with CHAP authentication:
    CentralA(config-if)#encapsulation ppp
    CentralA(config-if)#ppp authentication chap
  • To ensure that this interface will be using DDR on its async lines:
    CentralA(config-if)#dialer in-band
  • To make incoming calls, start either a PPP or an EXEC session:
    CentralA(config-if)#async mode interactive
  • To associate this interface with the dialer list 1:
    CentralA(config-if)#dialer-group 1
  • To have the incoming PPP session be issued an IP address from the ASYNCLAB pool of addresses:
    CentralA(config-if)#peer default ip address pool lab
  • To make the disconnect take place after 120 seconds without interesting traffic:
    CentralA(config-if)#dialer idle-timeout 120

Step 3

Configure the physical characteristics of the lines that are associated with the async-group interface. The following list shows the commands for the Step 3 configuration requirements:

  • To have the EXEC, IP, or SLIP session be automatically decided by the router upon receiving the first byte of data of the incoming connection:
    CentralA(config)#line 65 70
    CentralA(config-line)#autoselect during-login
    CentralA(config-line)#
    autoselect ppp
  • To have the router consult the local username database to authenticate callers:
    CentralA(config-line)#login local
  • To ensure that the modem can receive and place calls:
    CentralA(config-line)#modem inout
  • To have the router autoconfigure the MICA modem:
    CentralA(config-line)#modem autoconfigure type mica
  • To make the lines authorized to transport for input and output any traffic (Telnet, rlogin, lat, and so on):
    CentralA(config-line)#transport input all
  • To have the flowcontrol be done by the modem signaling with one stopbit:
    CentralA(config-line)#stopbits 1
    CentralA(config-line)#flowcontrol hardware

Step 4

The following shows how to configure the dialer interface to be used for receiving calls from the branch office. It also shows how to provide all the necessary commands for an authenticated PPP session, for identifying interesting traffic, and any other commands you should configure on a dialer interface:

CentralA(config)#interface dialer 1
CentralA(config-if)#ip address 10.130.0.2 255.255.255.0
CentralA(config-if)#dialer in-band
CentralA(config-if)#dialer idle-timeout 60
CentralA(config-if)#dialer-group 1
CentralA(config-if)#no fair-queue
CentralA(config-if)#encapsulation ppp
CentralA(config-if)#ppp authentication chap
CentralA(config-if)#no peer default ip address
CentralA(config-if)#ppp multilink
CentralA(config-if)#dialer remote-name BranchA
CentralA(config-if)#dialer string 7782001
CentralA(config-if)#
dialer pool 1

Step 5

To assign a static route to reach the branch office by using the dialer interface and to prevent IGRP routing updates from going out of your interface dialer:

CentralA(config)#ip route 10.218.0.0 255.255.255.0 dialer 1
CentralA(config)#router igrp 100
CentralA(config-router) #passive-interface dialer 1

The new configuration can be seen in bold letters in Figure .