Troubleshooting guide

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ATM and Layer 3 Switch Router Troubleshooting Guide
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Chapter 11 Troubleshooting Layer 3 Network Connections
Troubleshooting IP Layer 3 Connections
Step 9 From the Catalyst 8540-1, use the show epc if-entry interface command with the entry interface
parameters to display the status of the Broute VC.
C8540CSR-1# show epc if-entry interface FastEthernet 1/0/15 entry GigabitEthernet 0/0/0
IF Entry for GigabitEthernet0/0/0 on FastEthernet1/0/15
Mac(hex) - 00:90:21:CC:CC:CC
isMyInteface : False isSubInterface : False
Status Up Broute VC - 67 Bcast VC - 0
Netmask: 24
FEC disabled
Trunking Disabled
State : Not-Applicable/Listening/Blocking
Bridge-Group disabled
IP routing on bridging off
IPX routing off bridging off
Appletalk routing off
In Encapsulation:
ICMP Redirect enabled Unreachable enabled
IP Multicast disabled: ttl-threshold: 0
Verify the following:
• MAC address shown is that of the entry interface.
• Broute VC field status is up.
• IP routing is on.
Workarounds
For inconsistencies between the adjacency table and the EPC IP address table, use the clear arp or clear
adjacencies commands to rebuild the table. When you use one of these commands, the switch router
sends an ARP request for all entries in the ARP cache. As replies come back, it will refresh the cache.
If any entries time out, they will be cleared from the table. The switch router will then build the
adjacency table using this information, and then populate the interface EPC IP address table.
If you find inconsistencies between the IP route table, CEF table, and the epc ip-prefix table, the clear
ip route command will rebuild the entries in these tables. You can either clear a specific route using the
clear ip route ip-address command or use the clear ip route * command to clear all routes. The routing
protocol should relearn the routes and then rebuild the CEF table. The switch router then passes this
information to the interfaces and into the ip-prefix tables.
Caution There will be a momentary spike in route processor activity and a corresponding traffic disruption.
Use caution when performing the previously described workarounds in a production network.
If you determine that the interface is configured incorrectly, refer to the “Configuring Interfaces” chapter
in the Layer 3 Switching Software Feature and Configuration Guide.