Software core is a central server which is located in TMCC. It has constant communication with local servers with which it exchanges information. This is the server that controls all local servers and all equipment.
Local servers are located in front of and in the back of the tunnel and they control all system in the tunnel as well as nearby signs in front and in the back of the tunnel. It is important to emphasize that servers are placed in pairs to act as a back-up to each other (Hot redundancy). They are usually located in trafo-station (one on each side of the tunnel).