Abstract: The time synchronization of a network is protected against unauthorized changes to the grandmaster clock of a base time domain by monitoring the physical communication interfaces of a network device for arrival of messages relating to time synchronization. If the messages relating to time synchronization apply to the initially set-up and synchronized base time domain, a check is performed to determine whether the messages relating to time synchronization announce a new grandmaster clock having better clock parameters than those of the present grandmaster clock. If so, a virtual base time domain is started by the network device. If the verification reveals that the proposed new grandmaster clock is trustworthy or valid, the network device discontinues the virtual time domain, updates its stored information concerning the grandmaster clock and, from this time onward, sends messages relating to time synchronization that are based on the new clock parameters to the network.

Abstract: A method for operating an Ethernet on-board electrical system of a motor vehicle includes determining a propagation time or delay of a first signal on a first connection path between a first control unit of the Ethernet on-board electrical system and a second control unit of the Ethernet on-board electrical system. A maximum speed of the first connection path is determined. A type of transmission medium of the first connection path is determined on the basis of the connection delay and the maximum speed. A control unit for an Ethernet on-board electrical system and an Ethernet on-board electrical system for a motor vehicle are also provided.

Abstract: The time synchronization of a network is protected against unauthorized changes to the grandmaster clock of a base time domain by monitoring the physical communication interfaces of a network device for arrival of messages relating to time synchronization. If the messages relating to time synchronization apply to the initially set-up and synchronized base time domain, a check is performed to determine whether the messages relating to time synchronization announce a new grandmaster clock having better clock parameters than those of the present grandmaster clock. If so, a virtual base time domain is started by the network device. If the verification reveals that the proposed new grandmaster clock is trustworthy or valid, the network device discontinues the virtual time domain, updates its stored information concerning the grandmaster clock and, from this time onward, sends messages relating to time synchronization that are based on the new clock parameters to the network.

Abstract: A node may determine the topology of a computation system. The computation system is a network of nodes and multiple nodes are capable of being a grandmaster clock source. The method includes starting a best clock selection process, announcing clock information, and if the node is not acting grand master then receiving messages announcing clock information from other nodes of the network. Topology information is extracted from the messages, and if the node is acting grandmaster then retiring from the position of grandmaster. The best clock selection process steps are repeated until no node of the network becomes acting grandmaster.

Abstract: A node may determine the topology of a computation system. The computation system is a network of nodes and multiple nodes are capable of being a grandmaster clock source. The method includes starting a best clock selection process, announcing clock information, and if the node is not acting grand master then receiving messages announcing clock information from other nodes of the network. Topology information is extracted from the messages, and if the node is acting grandmaster then retiring from the position of grandmaster. The best clock selection process steps are repeated until no node of the network becomes acting grandmaster.

Abstract: A method for operating an Ethernet on-board electrical system of a motor vehicle includes determining a propagation time or delay of a first signal on a first connection path between a first control unit of the Ethernet on-board electrical system and a second control unit of the Ethernet on-board electrical system. A maximum speed of the first connection path is determined. A type of transmission medium of the first connection path is determined on the basis of the connection delay and the maximum speed. A control unit for an Ethernet on-board electrical system and an Ethernet on-board electrical system for a motor vehicle are also provided.