This topic describes the issues that you may encounter when you use the Application Topology Composer (ATC) feature and the corresponding solutions.

Issues related to connectivity

The following figure shows the result returned by the test engine:
telnet XX isConnected false, please check the instance isReachable, execute ping [ip] or telnet [ip] [port]

The test engine uses Telnet to check whether the destination port is reachable. If the destination port is unreachable, check whether the desired application can listen to the port. This issue occurs when the trace data is empty because the request is not sent to the destination node.

Empty instance list

The test engine discovers instances in an application by reading the service list of the application. The following figure shows the list of instances that are normally registered for services:

Empty instance list

If the instance list is empty, check whether your application is registered for services.

Issues related to traces

Trace

Only EDAS applications have traces. Therefore, when you select EDAS application for Type, you can click a trace to access it. If you select another value for Type, you cannot access a trace by clicking it. If a service of another type indirectly calls an EDAS application, you can query the trace according to the displayed trace ID.