Honeywell International Inc.

Tttech Computertechnik Ag

Ittech Computertechnik Aktiengesellschaft

Matthias Wachter

Brendan Hall

Michael Paulitsch

Wilfried Steiner

Kevin Raymond Driscoll

Hermann Kopetz

Harald Angelow

The invention relates to a method for synchronizing local clocks in a distributed computer network, where said computer network consists of a number of components that are connected to each other via bi-directional communication links, characterized in that

Method for synchronizing local clocks in a distributed computer system

The goal of the present invention is to improve the useful data efficiency and reliability in the use of commercially available ETHERNET controllers, in a distributed real time computer system, by a number of node computers communicating via one or more communication channels by means of TT ETHERNET messages. To achieve this goal, a distinction is made between the node computer send time (KNSZPKT) and the network send time (NWSZPKT) of a message. The KNSZPKT must wait for the NWSZPKT, so that under all circumstances, the start of the message has arrived in the TT star coupler at the NWSZPKT, interpreted by the clock in the TT star coupler. The TT star coupler is modified, so that a message arriving from a node computer is delayed in an intelligent port of the TT star coupler until the NWSZPKT can send it precisely at the NWSZPKT into the TT network.

Communication method for the transmission of TT ethernet messages in a distributed real time computer system

A method for synchronizing local clocks in a distributed computer network includes a number of components that are connected to each other via bi-directional communication links. An a priori configured set of components generates synchronization messages and sends these messages to the network. An a priori configured set of components consumes the generated messages. One or more message-relaying components in between a component that generates a synchronization message and the component that consumes the message adds delay value to the message reflecting the delay imposed by the message-relaying component. A component that is configured to consume a synchronization message delays a received synchronization message upon reception for a duration that is calculated by an a priori configured value for the maximum transmission delay minus the value of the sum of all delay values added to the received message before further usage of the message in the synchronization process.

Method for synchronizing local clocks in a distributed computer network

A method for synchronizing local clocks in a distributed computer network, wherein end systems and switches of the network executes the method as a synchronization state machine, which uses three different frame types. The states in the state machine belong to an unsynchronized or to a synchronized set of states. All end systems being configured as Synchronization Master periodically send coldstart frames in one of the unsynchronized states, all end systems being configured as Synchronization Master react to the reception of a coldstart frame by sending a coldstart acknowledgment frame a first timeout after the reception of the coldstart frame on all replicated communication channels. First timeout is reset when a consecutive coldstart frame is received before the coldstart acknowledge is sent, and all Synchronization Masters react to the reception of a coldstart acknowledgment frame by starting a second timeout and enter a synchronized state when the second timeout expires.

Method and systems of transmission schedule enforcement in a hub-based network is provided. Method includes receiving guardian messages from one or more of a plurality of nodes, implementing a voting function, voting the received guardian messages using the voting function, and when a clear winner of the received guardian messages is detected, enabling a port indicated by the clear winner to propagate. The guardian messages are received outside of TDMA communications. The guardian messages contain information pertaining to the next slot or slots to transmit.

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Vienna, Austria

Matthias Wachter