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Software Configuration Guide for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
OL-1957-04
Chapter3 Configuring with the Command-Line Interface
Configuring the Digital Modem Network Module for the Cisco 3640 Router
For more information about configuring E1 ISDN D-channel serial interfaces, refer to the “Configure
ISDN PRI” section in the Cisco IOS Release 11.3 Dial Solutions Configuration Guide.
Configure the ISDN D-Channel Serial Interface for T1 Modules
To configure the ISDN D-channel serial interface for T1 modules, perform the following tasks,
beginning in the global configuration mode:
For more information about configuring T1 ISDN D-channel serial interfaces, refer to the “Configure
ISDN PRI” section in the Cisco IOS Release 11.3 Dial Solutions Configuration Guide.
Configure the Loopback Interface
The loopback 0 interface is the interface dial-in users access when dialing in to the network. Usually, all
dial-in users are assigned to a single IP subnet. This subnet can be identified with the loopback 0
interface, a logical interface whose network number can be borrowed by each asynchronous dial-in
interface.
To configure the loopback 0 interface, perform the following tasks, beginning in global configuration
mode:
no cdp enable
Disable Cisco Discovery Protocol (CDP) on this
interface.
Command Description
interface Serialslot/port:23
Specify the D-channel of the first PRI line and
switch to the interface configuration mode.
no ip address
Disable IP processing on this interface.
encapsulation ppp
Set the Point-to-Point Protocol (PPP) as the
encapsulation method used by this interface.
isdn incoming-voice modem
Configure all incoming voice calls to go to the
modems.
dialer rotary-group number
Create a rotary dialer group.
dialer-group number
Assign the D-channel interface(s) to the defined
rotary dialer group.
no fair-queue
Disable fair weighted queuing for this interface.
no cdp enable
Disable CDP on this interface.
Command Description
Step1
interface Loopback number
Select the loopback 0 interface.
Step2
ip address ip-address ip-address
mask
Assign an IP address and subnet mask to
the loopback 0 interface.