Gathering Information on Application Layer Problems
Cisco IOS commands

The following highlights some of the most common and useful commands.

The show commands help monitor installation behavior and normal network behavior, as well as isolate problem areas.

The debug commands assist in the isolation of protocol and configuration problems.

Use show commands for the following activities:

  • Monitoring router behavior during initial installation
  • Monitoring normal network operation
  • Isolating problem interfaces, nodes, media, or applications
  • Determining when a network is congested
  • Determining the status of servers, clients, or other neighbors

Use debug commands to isolate problems, not to monitor normal network operation. Use debug commands to look for specific types of traffic or problems after narrowing the problems to a likely subset of causes.

Figure shows examples of IOS troubleshooting commands.