Systems and methods, including computer program products, providing high-availability in server systems. The network communication system comprises a plurality of control units respectively connected to internal LANs, which connect internal units mutually. A clock signal selector circuit selects and outputs the clock signal when a load increases and the on duty of the secondary current reaches the predetermined value. The first electrical line is connected to the base body in the region of the second end thereof, and means are provided for reversibly fixing the fixing element to the first electrode. The rolling elements are positioned in the rolling element pockets such that a centerline of each rolling element lies in or in proximity to the given plane.