Troubleshooting guide

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ATM and Layer 3 Switch Router Troubleshooting Guide
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Chapter 5 Troubleshooting Switch Router ATM Interface Connections
Troubleshooting Channelized DS3 and E1 Frame Relay Interfaces
Step 3 Check the line protocol field to see if the status is up.
If the interface is down, check for the following:
• The line protocol software processes might have determined that the line is unusable. Try swapping
the cable.
• The local or remote interface might be misconfigured. Check the interface configuration.
• Clocking might be misconfigured or the source interface might have failed. Refer to the “Initially
Configuring the ATM Switch Router” chapter in the
ATM Switch Router Software Configuration Guide.
• Hardware might have failed. Try swapping the port adapter.
Step 4 Check the Encapsulation field. Confirm that the encapsulation method matches the interface type.
Step 5 Check the Last input or the Last output fields. They show the number of hours, minutes, and seconds
since the last packet was successfully received or transmitted by the interface.
Step 6 Check the output hang field. It shows the number of hours, minutes, and seconds since the last reset
caused by a lengthy transmission.
Step 7 Check the CRC field. The presence of many CRC errors but not many collisions is an indication of
excessive noise. If the number is too high, check the cables to determine if any are damaged. If you are
using UTP cables, make sure you are using category 5 cables and not another type, such as category 3.
Note Errors and the input and output difference should not exceed 0.5 to 2.0 percent of traffic on
the interface.
If you determine that the physical interface is configured incorrectly, refer to the “Configuring
Interfaces” chapter in the ATM Switch Router Software Configuration Guide.