An agent can log on to the AE system only once. Whenever an attempt is made to log on, the Automation Engine checks whether an agent connection of the same name already exists.
The agent starts and tries to log on to the AE system. The Automation Engine finds that there is no agent connection of the same name. Thus, it accepts this login attempt and stores the agent's name, port number, start time etc. It deletes this information when the particular agent connection ends. Doing so ensures a clear overview of agent connections.
If the Automation Engine detects that an agent of the same name has already logged on, it tries to establish contact. The time span in which the Automation Engine waits for a response can be specified in its INI-file parameter duplicateTimeout= (section [TCP/IP]. If the agent responds within the specified time span, the Automation Engine rejects the double attempt to log on. If the agent does not respond, the Automation Engine accepts the double attempt to log on and updates the login information (such as the start time).