Connection to the Application (Connectivity) 
TREX can communicate with the application using it by means of an HTTP connection or an RFC connection:
ABAP application accesses TREX by means of an ABAP client (RFC connection)
As a rule, ABAP applications communicate with the TREX servers through the TREX ABAP client using the RFC/SNC protocol. Communication takes place using an instance of the SAP Gateway and an RFC server.
Java application accesses TREX by means of a Java client (HTTP connection)
As a rule, Java applications communicate with the TREX servers by means of the TREX Java client using the HTTP or HTTPS protocol. This communication takes place using a Web server that is enhanced with TREX-specific functions.
To connect TREX to the application using TREX for the first time, work through the steps described in TREX Post-Installation Configuration and Connecting TREX with an Application directly after the installation.
You work through these and further configuration steps for connecting to the application using TREX using the functions in the TREX admin tool (standalone).
In the landscape administration in the area, the following functions are available:
Connectivity window
RFC tab
Current
You administrate and configure the RFC connection here:
Repair History
You can monitor the progress of automatic recovery processes (repairs) for the RFC connection here. The system displays information about the Repair Time, the SAPSID user, the type of RFC server (multi/single-threaded), the problem that occurred, and the Solution (Action).
Http tab
You monitor and configure the TREX Web server here: