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 DS3 and E3 Interfaces
Step 2 Check the IF Status and Admin Status fields to see whether they are up.
If down, check for the following:
• Disconnected or faulty cabling—Check cables.
• Hardware failure—Swap hardware.
If administratively down, the interface has been administratively taken down. Use the no shutdown
interface configuration command to reenable the interface.
Step 3 Check the Input cells and Output cells fields. If the errors and the input and output difference exceed
0.5 to 2.0 percent of traffic on the interface, the interface is experiencing congestion and dropping cells.
Step 4 Check the AAL5 crc error field. If the errors and the input and output difference exceed
0.5 to 2.0 percent of traffic on the interface, check for the following:
• Many CRC errors, but not many collisions. This indicates excessive noise.
• Cable damage. If you are using UTP cables, make sure you are using category 5 cables and not
another type, such as category 3.
If you determine that the physical interface is configured incorrectly, refer to the “Configuring
Interfaces” chapter in the ATM Switch Router Software Configuration Guide.