Troubleshooting guide

6-60
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 to determine where the cells are being dropped along the length
of the circuit:
Step 1 Use the show atm vc traffic interface atm command to look for mismatching numbers on both ends of
the cable starting with the backbone interface connection at the switch router in the administration
building and ending with the backbone interface connection at the manufacturing building.
AdminFl1Ls1# show atm vc traffic interface atm 1/0/0
Interface VPI VCI Type rx-cell-cnts tx-cell-cnts
ATM1/1/0 0 5 PVC 672286 672286
ATM1/1/0 0 16 PVC 45 45
ATM1/1/0 0 18 PVC 730020 730155
ATM1/1/0 12 67 PVC 0 0
AdminFl1Ls1#
Step 2 Use the show atm vc traffic interface atm command to look for mismatching numbers on the interface
connection at the switch router in the manufacturing building.
ManuFl1Ls1# show atm vc traffic interface atm 0/1/0
Interface VPI VCI Type rx-cell-cnts tx-cell-cnts
ATM0/1/0 0 5 PVC 672286 672286
ATM0/1/0 0 16 PVC 45 45
ATM0/1/0 0 18 PVC 730020 730155
ATM0/1/0 12 67 PVC 0 0
ManuFl1Ls1#
Step 3 Use the show atm vc traffic interface atm command to look for mismatching numbers on the interface
connection between the ATM switch router and the Catalyst 5000 Fast Ethernet switch in the
manufacturing building.
ManuFl1Ls1# show atm vc traffic interface atm 4/0/0
Interface VPI VCI Type rx-cell-cnts tx-cell-cnts
ATM4/0/0 0 5 PVC 672286 672286
ATM4/0/0 0 16 PVC 45 45
ATM4/0/0 0 18 PVC 730020 155
ATM4/0/0 12 67 PVC 0 0
ManuFl1Ls1#
Notice that the number of received and transmitted cell counts are vastly different, which indicates that
this is the interface where the cells are being dropped.
Continue with the next phase of troubleshooting to determine why the cells are being dropped.
Checking Line and Circuit Oversubscription
Use the following commands to check for oversubscription of the line and circuit under test:
Command Purpose
show interfaces atm card/subcard/port Checks to see if the line is oversubscribed.
show atm interface atm card/subcard/port Checks to see if the circuit is oversubscribed.