The topics and questions that this chapter addresses include the following:
Enabling Frame Relay encapsulation
Configuring LMI type on a Frame Relay interface
Configuring static and dynamic DLCI to network layer address mapping
Configuring Frame Relay subinterfaces
Configuring point-to-point subinterfaces
Configuring multipoint subinterfaces
Configuring a Cisco router as a Frame Relay switch
Configuring Frame Relay switching using a local significance approach to DLCI assignment
Configuring Frame Relay switching using a global significance approach to DLCI assignment
Verifying Frame Relay connections with Cisco IOS show commands
Troubleshooting Frame Relay connections with IOS debug commands
After completing this chapter, readers will be able to perform the basic Frame Relay configuration commands with the Cisco IOS software. Readers will be able to configure a basic Frame Relay network involving Cisco equipment and to perform basic monitoring and troubleshooting using relevant Cisco IOS show and debug commands.
Configuring Frame Relay
Frame Relay is configured on the Cisco router via the text-based Cisco IOS Command Line Interface (CLI). This section looks at the configuration commands required to configure basic Frame Relay operation on a Cisco router.
A basic setup involving the hardware configurations depicted in Figure 4-1 is used for this discussion and for illustration purposes. In the later part of this chapter, additional hardware will be required to explain more complex configuration tasks. In the setup used in this chapter, the Cisco routers are configured as Frame Relay access devices, or data terminal equipment (DTE), connected directly to a dedicated Frame Relay switch, or data circuit-terminating equipment (DCE). Note that Cisco routers can be configured to operate similarly as a Frame Relay switch as well. The configuration tasks will be fully explained in a later section.
Figure 4-1 Frame Relay Hardware Configuration
Different Cisco IOS software versions or releases may display slightly different outputs. To maintain consistency of the Cisco IOS Software Version, IOS 12.2(1) release is loaded on all routers used in the configuration examples of this chapter.
Example 4-1 displays the show output of the show version command on R1.
Example 4-1 IOS Version Loaded on the Lab Routers
R1#show version Cisco Internetwork Operating System Software IOS (tm) 7200 Software (C7200-JS-M), Version 12.2(1), RELEASE SOFTWARE (fc2) Copyright (c) 1986-2001 by cisco Systems, Inc. Compiled Thu 26-Apr-01 22:10 by cmong Image text-base: 0x60008960, data-base: 0x616B0000