Safety-relevant data in a motor vehicle is transmitted by means of an Ethernet standard via at least one intermediate node in an Ethernet packet. Each intermediate node receives an Ethernet packet, evaluates it, and forwards it accordingly. Provision is made for a data type for safety-relevant data to be transmitted in communication information in the Ethernet frame with the safety-relevant data, for each intermediate node to check the communication information from the data contents of the Ethernet frame in the received Ethernet packet for the presence of the data type for safety-relevant data, for each intermediate node to duplicate an Ethernet frame, which contains the data type for safety-relevant data in the communication information, at least once, and for each intermediate node to emit the duplicated Ethernet frame in a new Ethernet packet.