Troubleshooting guide

6-61
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 6 Troubleshooting Switch Router ATM Network Connections
Troubleshooting Dropped Connections
Follow these steps to troubleshoot a VC by checking for oversubscription of the line and circuit
under test:
Step 1 Use the show interface atm command to check ATM interface 1/0/0 for oversubscription.
Step 2 Use the show atm interface atm command to check ATM interface 4/0/0 for oversubscription.
If the line or circuit is oversubscribed, causing cells to be dropped, add more interfaces or circuits
between the switch routers.
If you determine that the line or circuit is oversubscribed, see the “Configuring Virtual Connections”
chapter in the ATM Switch Router Software Configuration Guide.
Continue with the next phase of troubleshooting if you still have not determined why the cells are
being dropped.
Checking Traffic Priority
If a circuit is configured with multiple traffic types and some have a higher priority or QoS, cells with a
lower priority are going to be dropped on a congested circuit.
For detailed configuration information, see the “Configuring Resource Management” chapter in the ATM
Switch Router Software Configuration Guide.
Use the following commands to determine the configuration cell traffic priority and policing:
Follow these steps to determine the configuration cell traffic priority and policing:
Step 1 Use the show atm interface resource atm command to confirm traffic priority.
Step 2 Use the show atm vc interface atm command to confirm traffic policing.
If you determine that traffic priority or policing is causing cells to be dropped, see the “Configuring
Resource Management” chapter in the ATM Switch Router Software Configuration Guide.
Continue with the next phase of troubleshooting dropped cells if you still have not determined the cause
of the problem.
Command Purpose
show atm interface resource atm card/subcard/port Confirms the configuration of resource
management looking for traffic priority
conflicts.
show atm vc interface atm card/subcard/port vpi vci Confirms the configuration of the VC
looking for policing conflicts.