A switch is a coupling element that interconnects several locations of a network. In an ethernet-network with star topology, the switch is responsible for distributing the data packets. This function is similar to a Hub, however, the switch can produce a direct connection between the connected devices. In this case, it must be familiar with the recipients’ port of the data packets, otherwise it transfers the packets to all ports. If a recipient returns response packets, the switch remembers the Media Control Access addresses of the data packets and the port belonging to it. Datapackets are only sent to this point.