Method for transmitting messages in an industrial communication network which can be redundantly operated, in which - messages are transmitted in a first subnetwork with a tree topology in accordance with a spanning tree protocol, communication devices associated with network nodes of the first subnetwork interchanging messages containing topology information with one another in order to form a tree topology, and a root network node being determined as the basic element of a tree topology by the communication devices associated with the network nodes of the first subnetwork on the basis of the interchanged topology information, and loop-free connections being set up from the root network node to the remaining network nodes of the first subnetwork, - messages are transmitted in a second subnetwork in accordance with a parallel or ring redundancy protocol, - the first and second subnetworks are coupled to one another via a plurality of communication devices, - a virtual network node which is connected to all network nodes of the second subnetwork via a respective virtual connection which cannot be interrupted by an error is configured as the root network node of the first subnetwork, - topology information for the first subnetwork, which comprises the virtual network node, is configured as received topology information for the first subnetwork at a respective virtual terminal connection of communication devices associated with the network nodes of the second subnetwork, - failure of a communication device associated with a network node of the second subnetwork or of a connection between two network nodes of the second subnetwork is handled solely in accordance with the parallel or ring redundancy protocol, a configuration of the virtual network node as the root network node of the first subnetwork being retained. - messages are transmitted in a first subnetwork with a tree topology in accordance with a spanning tree protocol, communication devices associated with network nodes of the first subnetwork interchanging messages containing topology information with one another in order to form a tree topology, and a root network node being determined as the basic element of a tree topology by the communication devices associated with the network nodes of the first subnetwork on the basis of the interchanged topology information, and loop-free connections being set up from the root network node to the remaining network nodes of the first subnetwork, - messages are transmitted in a second subnetwork in accordance with a parallel or ring redundancy protocol, - the first and second subnetworks are coupled to one another via a plurality of communication devices, - a virtual network node which is connected to all network nodes of the second subnetwork via a respective virtual connection which cannot be interrupted by an error is configured as the root network node of the first subnetwork, - topology information for the first subnetwork, which comprises the virtual network node, is configured as received topology information for the first subnetwork at a respective virtual terminal connection of communication devices associated with the network nodes of the second subnetwork, - failure of a communication device associated with a network node of the second subnetwork or of a connection between two network nodes of the second subnetwork is handled solely in accordance with the parallel or ring redundancy protocol, a configuration of the virtual network node as the root network node of the first subnetwork being retained.