background image
78 Chapter 4: Configuring Asynchronous Connections with Modems
Basic Asynchronous Configuration
To configure the modem (the DCE) from the router (the DTE), you must set up the logical and
physical parameters for the connection. The logical parameters include the protocol addressing,
the authentication method, and the encapsulation, all of which are configured on the
asynchronous interface. The physical configuration is done on the line. The physical parameters
include the flow control, the DTE-DCE speed, and the login request. It is important for the
successful CCNP or CCDP to be aware of the command mode needed for configuration.
The configuration in Example 4-4 demonstrates which commands are used on each line or
interface.
autoselect during-login
autoselect ppp
login local
modem InOut
transport input all
stopbits 1
speed 115200
flowcontrol hardware
line aux 0
line vty 0 4
login local
!
Example 4-4
Configuration for a Serial Interface in Asynchronous Mode
interface Serial3/0 !logical parameters go on the interface
physical-layer async
ip unnumbered Ethernet0/0
no ip directed-broadcast
encapsulation ppp
async mode interactive
peer default ip address pool remaddpool
no cdp enable
ppp authentication chap
line 97 !physical parameters go on the line
autoselect during-login
autoselect ppp
login
modem InOut
modem autoconfigure type usr_sportster
transport input all
stopbits 1
rxspeed 115200
Example 4-3
3640 Router Configuration (Continued)