3Com MSR 50 Series Configuration Manual page 195

[RouterA] user-interface tty1
[RouterA-ui-tty1] modem both
2 Configure Router B
# Configure a dial access control rule for dialer access group 2; and create a local
user account usera for Router A and configure PPP authentication for it.
<RouterB> system-view
[RouterB] dialer-rule 2 ip permit
[RouterB] local-user usera
[RouterB-luser-usera] password simple usera
[RouterB-luser-usera] service-type ppp
[RouterB-luser-usera] quit
# Assign an IP address to interface Serial 2/0, configure its physical layer and
C-DCC parameters.
[RouterB] interface serial 2/0
[RouterB-Serial2/0] ip address 100.1.1.2 255.255.255.0
[RouterB-Serial2/0] physical-mode async
[RouterB-Serial2/0] async mode protocol
[RouterB-Serial2/0] dialer enable-circular
[RouterB-Serial2/0] dialer-group 2
[RouterB-Serial2/0] link-protocol ppp
[RouterB-Serial2/0] ppp authentication-mode pap
# Specify the local end as the callback server, and set the callback reference to
user. In this case, DCC identifies the dial string for callback according to the
username configured in the dialer route command.
[RouterB-Serial2/0] dialer callback-center user
[RouterB-Serial2/0] dialer route ip 100.1.1.1 user usera 8810048
[RouterB-Serial2/0] ppp callback server
[RouterB-Serial2/0] quit
# Configure the user interface to be used and enable modem dialup on it.
[RouterB] user-interface tty2
[RouterB-ui-tty2] modem both
Solution 2: Use C-DCC to implement PPP callback, allowing the callback server to
identify the dial string for callback by comparing the remote username received in
PPP authentication against the local user database for a match.
3 Configure Router A
# Configure a dial access control rule for dialer access group 1.
<RouterA> system-view
[RouterA] dialer-rule 1 ip permit
# Assign an IP address to interface Serial 2/0, configure its physical layer and
C-DCC parameters.
[RouterA] interface serial 2/0
[RouterA-Serial2/0] ip address 100.1.1.1 255.255.255.0
DCC Configuration Example 195