4000 Router Series Layer 2 - WAN Configuration Guide

Task Remarks

Setting the operating mode for physical interfaces

Optional.

Skip this task when you configure ISDN BRI or PRI

interfaces.

Configuring link layer/network/routing protocols on

the dialup interface

Required.

Configuring a dial access rule Required.

Setting the operating mode for physical interfaces

For a synchronous/asynchronous serial interface, set its operating mode depending on the connected

modem. If the connected modem is asynchronous, set the interface to operate in asynchronous mode,

and then enable modem dial on the corresponding user interface. If the connected modem is

synchronous, set the interface to operate in synchronous mode.

By default, a synchronous/asynchronous serial interface operates in synchronous mode, and an

asynchronous serial interface operates in asynchronous mode.

For more information, see Interface Configuration Guide and "Managing a modem."

Configuring link layer/network/routing protocols on the dialup

interface

In dialup interface (physical or dialer interface) view, configure the link layer protocol (which can only be

PPP for a dialer interface) by using the link-protocol command, and assign the dialup interface an IP

address by using the ip address command.

In system view, perform other configurations.

When PPP encapsulation is configured, you can also configure PAP or CHAP authentication. Consider

the following when you configure PPP-related commands:

• In the C-DDR approach, make the configuration on dialer interfaces.

• In the B-DDR approach, make the configuration on dialer interfaces and preferably the same

configuration on physical interfaces on the calling side to guarantee the reliability of PPP link

parameters negotiation. On the called side, make the configuration on physical interfaces.

For more information, see Layer 2—WAN Configuration Guide, Layer 3—IP Services Configuration

Guide, and Layer 3—IP Routing Configuration Guide.

Configuring a dial access rule

You can configure a dial access rule to filter traffic traversing a dialup interface. Packets include the

following categories, depending on whether they comply with the permit or deny statements in the dial

access rule:

• Interesting packets—Packets matching a permit statement or that do not match any deny statements.

When receiving such a packet, DDR either sends it out if a link is present and resets the idle-timeout

timer, or originates a new call to set up a link if no link is present.