The invention relates to a method for operating a data network, and to a data network that is configured to work together with a ring structure-incompatible data transmission protocol. A plurality of network connection devices (2), 2M are interconnected by transmission paths (3) while forming a network ring (1). The latter each comprise at least one first transmission channel (4) having the data transmission protocol and at least one second transmission channel (5) having a data transmission method that is different from the data transmission protocol, wherein the first transmission channel (4) and the second transmission channel (5) are physically coupled with one another, as mechanically connected lines in a cable (3), for example. The first transmission channel is thereby used for transmitting user data NE, for example, audio and/or video data, but also control data, for example, for mixing consoles, illuminations, etc., which are transmitted via the ring structure-incompatible data transmission protocol, that is to say, in particular in the Ethernet. The network ring (1) is interrupted with respect to the first transmission channels (4) by way of a switching device (6), and ring-closure control data K are transmitted via the second transmission channels (5). In the event a connection error is detected, the switching device (6) is actuated such that the switching device switches from the open state into a closed state, in which the interruption of the network ring (1) caused by the switching device is suspended with respect to the first transmission channels (4). The connection device 2M acts within the shown network ring (1) as a control master switch and is responsible for the ring interruption with respect to the first transmission channel (4). A control device (7) of the control master switch 2M sends ring-closure control data K via one of the two ports (9) and checks whether or not these ring-closing control data K arrive again at the other port (8). The control devices (7) of the other connecting devices (2) are simply looped through these ring-closure control data K.