Beginning the Frame Relay Troubleshooting Process

The minimum information required before starting to troubleshoot includes the characteristics of the service such as: point-to-point or point-to-multipoint design; if routing or bridging is used; what are the remote and local DLCIs; and what is the access rate (link rate), CIR value, and IP addressing scheme. Regardless of the answer to these questions, some common indicators of the status allow you to start with the snapshot commands. The recommended commands are as follows:

 1602-frame#show ip interface brief 1602-frame#show interface serial 1 

The latter command depends on the configuration of the 160x router. This command can show the status of Serial 0 (for 56-kbps connections) and Serial 1 (if the router is equipped with a wide-area network interface card [WIC]).

NOTE

The truncated form of show ip interfaces brief is sh ip int brie.

Using the first command for a 56-kbps access rate service, the output in Example 17-1 is displayed.

Example 17-1. Output from the show ip interface brief Command for the 1602 Router, with a Built-In Data Service Unit/Channel Service Unit (DSU/CSU) for a 56-kbps Rate

 1604-frame#show ip interface brief Interface               IP-Address       OK? Method Status            Protocol Ethernet0               151.68.89.89     YES NVRAM  up                up Loopback0               unassigned       YES NVRAM  up                up ! This is your 56 Kbps connection Serial0                 unassigned       YES NVRAM  up                up Serial0.71              171.68.89.89     YES unset  up                up 

Example 17-2 shows the output from the show ip interface brief command when applied to 128 Kbps service.

Example 17-2. Output from the show ip interface brief Command for the 1602 Router, Equipped with a WIC Card

 1604-frame#show ip interface brief Interface         IP-Address        OK? Method Status                Protocol Ethernet0         121.70.194.209    YES NVRAM  up                    up Loopback0         unassigned        YES NVRAM  up                    up Serial0           unassigned        YES NVRAM  administratively down down ! This is your 128 Kbps connection Serial1           unassigned        YES NVRAM  up                    up Serial1.37        121.70.194.209    YES unset  up                    up 

The commands #show ip interface brief and #show interface serial 1(0) enable you to narrow the scope of the existing problem. The recommended troubleshooting process starts from the first layer (see Figure 14-1 in Chapter 14 and Figure 17-1).

Figure 17-1. Frame Relay Troubleshooting Tools