# Extended EtherCAT® Network Configuration (EXI)

The EC-Simulator stack has to know about the EtherCAT® bus topology and the cyclic/acyclic frames to exchange with the SubDevices. This configuration is determined in a configuration file which has to be available in the EtherCAT® Network Information Format (ENI). This format is completely independent from EtherCAT® SubDevice vendors, from MainDevice stack vendors and from EtherCAT® configuration tools. Thus inter-operability between those vendors is guaranteed.

Because the ENI file does not include information about the SubDevice hardware, the EXI (EtherCAT® Extended Information) file includes EEPROM content and SubDevice Object Dictionary from ESI and ESC register values from real network is typically needed. The EXI file can be exported using EC-Engineer.

![Diagram showing the relationship between the standard ENI format and the EC-Simulator EXI extended network information format including EEPROM content and object dictionary](../Media/EXI.png)

## SiL Simulation Software architecture

The SiL Simulation Software architecture does not need a physical network interface for SubDevice simulation. The EC-Simulator is loaded as Ethernet Driver instead to simulate the EtherCAT® Network on a System controller running the EC-Master.

![EC-Simulator SiL software architecture showing the simulator loaded as an Ethernet Driver on the System Under Test alongside EC-Master, requiring no physical network interface](../Media/SiL-architecture.png)