4000 Router Series Layer 2 - WAN Configuration Guide

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Figure 48 Network diagram for dial string backup/access service with DDR (ISDN mode)

Configuration procedure for PSTN mode

On Router A on the dialup side, configure circular dial string backup. On Router B, configure C-DDR to

allow the router to set up connections on eight asynchronous serial interfaces, and configure C-DDR

parameters on a dialer interface.

1. Configure Router A:

# Create dialer access group 1 and configure a dial access rule for it. Create a local user account

userb for Router B, and configure PPP authentication for the account.

<RouterA> system-view

[RouterA] dialer-group 1 rule ip permit

[RouterA] local-user userb class network

[RouterA-luser-network-userb] password simple userb

[RouterA-luser-network-userb] service-type ppp

[RouterA-luser-network-userb] quit

# Configure physical layer parameters for interface Serial 2/0 and enable PPP address

negotiation.

[RouterA] interface serial 2/0

[RouterA-Serial2/0] physical-mode async

[RouterA-Serial2/0] async-mode protocol

[RouterA-Serial2/0] ip address ppp-negotiate

# Configure PPP encapsulation and authentication on the interface.

[RouterA-Serial2/0] link-protocol ppp

[RouterA-Serial2/0] ppp authentication-mode pap

[RouterA-Serial2/0] ppp pap local-user user1 password simple user1

# On the interface, enable C-DDR, and configure C-DDR parameters and the dial strings for

reaching Router B.

[RouterA-Serial2/0] dialer circular enable

[RouterA-Serial2/0] dialer-group 1

[RouterA-Serial2/0] dialer route ip 100.1.1.254 8810048

[RouterA-Serial2/0] dialer route ip 100.1.1.254 8810049

...

[RouterA-Serial2/0] dialer route ip 100.1.1.254 8810055

[RouterA-Serial2/0] quit

# Configure the user interface to be used, and enable modem dial-in and dial-out on it.