Troubleshooting guide

11-34
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 11 Troubleshooting Layer 3 Network Connections
Troubleshooting IP Layer 3 Connections
• SRP—Indicates the prefix is a directly attached interface and these interfaces do not have a route in
the table, therefore packets from this network are sent to the route processor for processing. See the
earlier explanation in Step 7 for the entries per directly connected interface.
All interfaces should have the same CAM entries, since the forwarding decision is made based on
the information contained in the CAM table. This table is based on the network topology, not traffic
flows. The show epc ip-prefix command used with any other interface on the switch should contain
the same number of entries in the Total IP Prefix Entries in the CAM field (in this example, 25).
• CEF entries not populated—Indicates these network connections are missing the masklen /32. These
connections appear if you use the show epc ip-address command. In this example, you should
program all masklen as /30 and shorter prefixes.
Additionally, you can use other show epc ip-prefix interface command parameters to check the
cam-summary as well as the fail-entries and fail-summary.
C8540CSR-1# show epc ip-prefix interface FastEthernet 1/0/15 ?
A.B.C.D IP prefix to display
all-entries All IP Prefix entries
all-summary IP Prefix summary
fail-entries missing IP prefix entries
fail-summary Summary of missing IP prefixes
C8540CSR-1#
Step 2 From the Catalyst 8540-1, use the show epc ip-prefix interface command to display the connection
ingress interface to IP address 10.85.45.0.
C8540CSR-1# show epc ip-prefix interface FastEthernet 1/0/15 10.85.45.0 255.255.255.0
Prefix/Masklen Gateway1 Gateway2
10.85.45.0/24 10.85.66.5
The Gateway IP address should match the next hop IP address in the show epc cef command output in
Step 2 in the section “Checking the IP CEF Adjacencies” section on page 11-30.
To remove inconsistencies between the CEF table and the IP prefix table, use the clear ip route
command to rebuild these tables. You can either clear a specific route or use an asterisk (*) to clear all
routes.
Caution Use the clear ip route command carefully. It causes a temporary increase in switch router activity
which can lead to traffic disruptions.
Step 3 From the Catalyst 8540-1, use the show epc ip-address command with the IP address of the egress
interface to display the status of the MAC address rewrite.
C8540CSR-1# show epc ip-address interface FastEthernet 1/0/15 10.85.66.5
IPaddr: 10.85.66.5 MACaddr: 0090.21dd.dddd GigabitEthernet0/0/0 (4)
The information in this display should match the information shown using the show adjacency
command to display the MAC address rewrite in Step 3 of the “Checking the IP CEF Adjacencies”
section on page 11-30.
The display confirms the MAC address rewrite information as 0090.21dd.dddd, the Catalyst 8540-2
destination MAC address, and provides the interface index number, in this example “(4)”, to use in the
command in Step 5.
Step 4 From the Catalyst 8540-1, use the show epc lsipc command to display the status of the interprocess
information between the route processor and the Ethernet processor interfaces and Gigabit processor
interfaces.
C8540CSR-1# show epc lsipc