DDR 700: Static IP Routing To Another 700 Series Router

700 Series ISDN Dial-On-Demand Sample Configuration Static IP Routing To Another 700 Series Router	Cisco Fast Step Windows 95 Configuration Application

This sample configuration statically routes IP between two 700 series routers using PPP with CHAP authentication over ISDN. Unnumbered IP is used on the ISDN segment to help conserve network address space. With static routes between the two routers, there is no need for the routers to exchange routing updates and the ISDN line activates only when traffic demands. This is known as dial-on-demand routing (DDR).

An alternative to DDR using static routes is DDR using a snapshot routing protocol. Snapshot routing allows routes to be automatically exchanged during a defined time interval instead of burdening a network administrator with the chore of manually maintaining static routes. Although the ISDN line must be activated to exchange snapshot routing updates, the duration and frequency of the snapshot interval can be configured such that any associated ISDN costs are relatively negligible compared with the benefits of simplified network administration.

Get A Configuration Using Snapshot Routing
Faxback Doc #0502

As an added convenience, this configuration also includes the option to utilize the 700 series router's dynamic host configuration protocol (DHCP) server feature. With DHCP, the administrative burdens of configuring and maintaining IP information on each workstation can be greatly reduced. Workstations configured as DHCP clients automatically are assigned IP information (e.g. IP address, subnet mask, default gateway, etc.) by the router. The probability of IP configuration errors is greatly reduced when all IP information is controlled from a single point.

Note: DHCP commands may be ignored if the DHCP server feature is not desired.

Info On PPP
Faxback Doc #ppp

Info On IP Unnumbered
Faxback Doc #ip_unnum

Info On DHCP
Faxback Doc #dhcp

Before You Begin

Get The IOS-700 Command Glossary
Faxback Doc #0554

Detailed descriptions of all commands used in the 700 series router sample configurations. Also provides links to the 700 Command Reference if more information is required.

Preconfiguration Checklist

ISDN Information
The following info must be gathered from the ISDN service provider

ISDN Switch Type
ISDN SPIDs (where applicable)
In North America, SPIDs are required for all ISDN switch types except for 5ESS Custom Point-to-point
ISDN Directory Numbers
The directory number is the local seven digit ISDN phone number (no area codes) of your router

Network Information
The following info must be gathered from the network administrator

PPP Client Name
A PPP client name must be assigned to both locations
PPP Authentication Type
CHAP authentication is preferred and used in this example
PPP Password
A PPP password must be assigned to both locations
IP Address Information
An IP network design must be created
Phone Numbers
ISDN phone numbers of both locations

Atlanta Router Configuration Script

Boston Router Configuration Script

After You've Tried

You've tried the configuration and it doesn't work. Help is available!

Get 700 Series Router Troubleshooting Assistance
Faxback Doc #700_ts