Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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3.7 IPv4 network communication failures
3.7.1 Communication is not possible or is disconnected
There are three probable causes of problems that occur during communication on an IPv4 network
employing a Switch:
1. A configuration related to IP communication is changed.
2. The network configuration is changed.
3. A network device fails.
For causes 1 and 2, check the differences in the configuration and network configuration before
and after the change to uncover any cause that could disable communication.
This subsection describes the procedure for isolating the fault location to determine the cause of a
problem, and applies mainly to cause 3 failures. For example, IP communication might not be
possible even when the configuration and the network configuration are correct, or for operation
that hitherto has been normal, IP communication is no longer possible.
Use the following flowchart to isolate the fault location to identify the cause of the problem.