Abstract: According to the invention, in order that the asynchronous bandwidth available in a real-time capable Ethernet data network protocol can be better utilized without collision at least one slave (S1, . . . , Sn) which wishes to transmit asynchronous data informs the master (M) in a transmission cycle (Z(m)) by means of a request data packet (DPa) how much asynchronous data this slave (S1, . . . , Sn) wishes to transmit asynchronously and by means of an invitation data packet (DPe) the master (M) informs the slave (S1, . . . , Sn) as to the time (tas) within a following transmission cycle (Z(m+k+l)) at which the slave (S1, . . . , Sn) should transmit the asynchronous data in an asynchronous data packet (DPas).

Abstract: In order to be able to maintain cross-traffic between slaves in a ring topology of an Ethernet-based data network even in the event of an error in the ring topology, which leads to the interruption of the ring topology, it is provided that in the event of the occurrence (rectification) of an error (F) in the annular data network (1), the ringmaster is configured to forward data packets or to block at least multicast data packets, and that the master prompts the slaves (S1, S2), communicating with one another via cross-traffic, to transmit configuration data packets (DPMC1, DPMC2) as multicast data packets to each of the other slaves (S1, . . . , Sn) of the annular data network in order to adjust address tables (AT1, AT2) in the slaves (S1, S2), communicating with one another via cross-traffic.

Abstract: According to the invention, in order that the asynchronous bandwidth available in a real-time capable Ethernet data network protocol can be better utilized without collision at least one slave (S1, . . . , Sn) which wishes to transmit asynchronous data informs the master (M) in a transmission cycle (Z(m)) by means of a request data packet (DPa) how much asynchronous data this slave (S1, . . . , Sn) wishes to transmit asynchronously and by means of an invitation data packet (DPe) the master (M) informs the slave (S1, . . . , Sn) as to the time (tas) within a following transmission cycle (Z(m+k+l)) at which the slave (S1, . . . , Sn) should transmit the asynchronous data in an asynchronous data packet (DPas).

Abstract: In order to be able to maintain cross-traffic between slaves in a ring topology of an Ethernet-based data network even in the event of an error in the ring topology, which leads to the interruption of the ring topology, it is provided that in the event of the occurrence (rectification) of an error (F) in the annular data network (1), the ringmaster (RM) is configured to forward data packets or to block at least multicast data packets, and that the master (M) prompts the slaves (S1, S2), communicating with one another via cross-traffic, to transmit configuration data packets (DPMC1, DPMC2) as multicast data packets to each of the other slaves (S1, . . . , Sn) of the annular data network in order to adjust address tables (AT1, AT2) in the slaves (S1, S2), communicating with one another via cross-traffic.