Verify the adjacency table

The four commands that provide different hierarchical levels of information for the adjacency table are show adjacency, show adjacency summary, show adjacency detail, and show adjacency internal. Example 4-20 shows examples of these commands, respectively.

Example 4-20 Viewing Adjacency Table Details

Table 4-3 describes the most significant fields from the show adjacency commands in Example 4-20 for the purpose of troubleshooting. Verifying the information against the show ip route and show arp commands is necessary in verifying CEF consistency. If the values are not correct, disable CEF as a workaround and open a Cisco TAC case.

Table 4-3 show adjacency Command Field Descriptions

In Figure 4-3 and Example 4-5, the destination MAC address rewrite information from the show adjacency detail command in Example 4-20, 0008A37FCB7C, must match the MAC address from the show arp command. Otherwise, if the MAC address did not match, an inconsistency issue exists between the ARP table and adjacency table that needs to be investigated with the Cisco TAC.

Learn how to troubleshoot Cisco's Express Forwarding network switching technology in "Basic IP Connectivity and CEF Troubleshooting," Chapter 4 from the book Cisco Express Forwarding by Nakia Stringfield, Russ White and Stacia McKee.

Basic IP Connectivity and CEF Troubleshooting

  Introduction
  Accurately describe the problem
  Scope the network topology
  Review the OSI model for troubleshooting
  Verify the ARP table
  Verify the IP routing table
  Verify the CEF FIB table
  Verify the adjacency table
  Conduct hardware-specific troubleshooting

Reproduced from the book Cisco Express Forwarding. Copyright 2007, Cisco Systems, Inc. Reproduced by permission of Pearson Education, Inc., 800 East 96th Street, Indianapolis, IN 46240. Written permission from Pearson Education, Inc. is required for all other uses.