A stroke-variable engine includes a pivot shaft which is rotatably supported in a crankcase so as to be rotatable about an eccentric axis parallel to a crankshaft and which is connected to a control rod so that a rotational power reduced at a reduction ratio of 12 is transmitted from the crankshaft to the pivot shaft. An optoelectronic component emits light in a defined direction with respect to the mobile carrier. Network devices may communicate with legacy IPv4 networks while using IPv6 network addresses on an IPv6 network for local communications.