Defining Destination Parameters

Maps an IP network layer address to a remote phone number

Defines the method of reaching a remote ISDN destination

© 2004 Cisco Systems, In

When interesting traffic has been identified for the ISDN interface, the router initiates a DDR call, if the call is not already connected. The router uses the information that is configured in the dialer map command to determine dialing parameters to the destination router, such as the telephone number to dial. The dialer map command binds the next-hop protocol address to a telephone number, or dial-string, for a particular destination.

A dialer map is similar in concept to an Address Resolution Protocol (ARP) entry for a LAN that binds an IP address to a MAC address, or a Frame Relay map that binds a next-hop protocol address to a data-link connection identifier (DLCI). Each dialer map associates a destination or next-hop Layer 3 network address to a destination Layer 2 address.

The dialer map command options are described in the table.

dialer map Commands

Command

Description

dialer map protocol next-hop-address [name hostname] [speed 56|64] [broadcast] [dial-string[.isdn-subaddress]]

Configures a serial interface or ISDN interface to call one or multiple sites.

■ name parameter refers to the name of the remote system

■ speed parameter is the line speed to use in kilobits per second

■ broadcast parameter indicates that broadcasts should be forwarded to this address

■ dial-string[:isdn-subaddress] is the number to dial to reach the destination and the optional ISDN subaddress

[modem-script modem-regexp]

(Optional) Indicates the modem script to use for the connection (for asynchronous interfaces). Create modem-regexp using a chat script.

[system-script system-regexp]

(Optional) Indicates the system script to use for the connection (for asynchronous interfaces). Create system-regexp using a chat script.

Note The dialer map command has many other optional parameters available. For a complete description of the command and its parameters, refer to the documentation CD-ROM or http//www cisco com

Configuration of a Simple ISDN Call

This topic describes a simple ISDN BRI connection with DDR-enabled configuration.

Configuring a Simple ISDN Call

• Use PPP encapsulation

• All IP traffic to destination triggers ISDN call

• Carrier uses a 5ESS basic-rate switch

• Service provider assigns connection parameters

© 2004 Cisco Systems, Inc. All rights re

The figure displays an example of how you can combine the commands described in the previous lessons to set up ISDN and initiate DDR.

DDR is configured to connect RouterA to RouterB. Interesting traffic is defined as any IP traffic that will initiate a DDR call to RouterB. Similar to a telephone call, the number dialed is for the remote ISDN device. The ISDN service provider supplies this number.

As shown in the figure, traffic is routed to the LAN. Before a connection can be made, you must configure Challenge Handshake Authentication Protocol (CHAP) authentication, a dialer map, and static routes of how to reach the RouterB 192.68.1.0 network.

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