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.