Abstract: A system comprises a plurality of nodes; and a hub that is communicatively coupled to each of the plurality of nodes via a plurality of point-to-point links, wherein a priority-based arbitration scheme is used by the plurality of nodes and the hub to communicate over each of the plurality of point-to-point links. When the hub determines that one or more of the plurality of nodes is each transmitting a message having an identification field comprising a first sub-field and a second sub-field, the hub uses the first sub-field to select which node's message should be forwarded to the other nodes based, at least in part, on the priority-based arbitration scheme and forwards the selected node's message as it is received to the other nodes, continuing with the second sub-field of the selected node's message.

Abstract: Systems and methods for network clock synchronization are provided. In one embodiment, a method for clock synchronization in a braided ring network comprises: providing a schedule for a braided ring network comprising a plurality of nodes, wherein at least two nodes comprise a self-checking pair of a first node and a second node, the first node performing a method comprising: determining when a first rendezvous message is received from the second node; when the second rendezvous message is received, calculating a time difference between the send instance of the first rendezvous message and a local time; when the time difference is not greater than a reference bound, calculating a sending point for transmitting a synchronization message, wherein the sending point is calculated based on the time difference; and selectively sending the synchronization message to the braided ring network when the sending point is reached based on the time difference.

Abstract: A half-duplex communication network comprises a plurality of communication links, each link being configured a priori to communicate in one direction; and a plurality of nodes, each node coupled to a first and second direct neighbor nodes and a first and second skip neighbor nodes via the plurality of communication links. Each node comprises propagation logic adapted to arbitrate conflicts between concurrent messages based on at least one of higher level policies and a comparison between a priority of each message, wherein each node is adapted to communicate a message without waiting to determine if another node is transmitting another message with a higher priority.

Abstract: 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.

Abstract: A method of configuring a node comprises receiving a first message having a count field value from a first direct link; receiving a second message having a count field value from a first skip link; adjusting the count field value in the first message by a first adjustment amount; adjusting the count field value in the second message by a second adjustment amount; comparing the adjusted count field value in the first message with the adjusted count field value in the second message; if the adjusted count field value in the first message matches the adjusted count field value in the second message, using the adjusted count field value in the first message to determine a node identity for the node; and processing subsequent messages based on the node identity.

Abstract: A network comprises a plurality of nodes; a plurality of bi-directional point-to-point communication links, wherein a priority-based arbitration scheme is used to communicate over each of the plurality of point-to-point links; and a hub that is communicatively coupled to each of the plurality of nodes via the plurality of point-to-point links; wherein when the hub determines that one or more of the nodes is transmitting a message via the hub, the hub selects which node's message should be forwarded to the other nodes based, at least in part, on the priority-based arbitration scheme and forwards the selected node's message to the other nodes with elevated priority.

Abstract: In one embodiment, a node comprises an interface to communicatively couple the node to a plurality of independent communication links. The node changes the mode in which the node operates when the node receives an indicator on a plurality of the independent communication links.

Abstract: In one embodiment, a node comprises an interface to communicatively couple the node to a channel. The channel communicatively couples the node to a first neighbor node in a first direction and to a second neighbor node in a second direction. When the first neighbor node is scheduled to transmit and the node receives data from the first neighbor node via the channel, the node determines if the transmission of the data complies with a policy. When the transmission of the data does not comply with the policy, the node does at least one of: blocks the data from being relayed along the channel and relays the data along the channel with information indicating that the transmission of the data does not comply with the policy.

Abstract: A parasitic time synchronization network is provided including a plurality of nodes, one or more hubs, each hub having communication links with the plurality of nodes and one or more guardians. Each node is adapted to transmit and receive data and communicate with every other node through the one or more hubs. The communication links between any one hub and the plurality of nodes defines a communication channel. Each guardian is associated with one communication channel. Each node is assigned a time slot in which it is permitted to transmit data through an associated hub of the one or more hubs. A guardian of an associated channel blocks propagation of data transmissions between the plurality of nodes through the associated hub allows only data transmissions from one of the plurality of nodes, wherein the guardian periodically receives a cluster of beacons generated by a plurality of the plurality of nodes.

Abstract: A method for controlling start-up of a network is provided. The method includes receiving a message from one node of a plurality of nodes at a hub while the network is in an unsynchronized state, relaying the message to the other nodes of the plurality of nodes of the network independent of the content of the message, and blocking all messages from the one node of the plurality of nodes until a relaying condition is met.

Abstract: A method of verifying the accuracy of blocks of data. In one embodiment, a method of verifying the accuracy of data in a message that includes a checking mechanism with hidden data is provided. The method comprises observing two or more initial messages. Comparing the residual error of each of the observed initial messages. If the residual errors of at least two of the initial messages match each other, storing the matched residual error. For subsequent messages, comparing residual errors of the subsequent messages with the stored matched residual error.

Abstract: In one embodiment, a network comprises a plurality of nodes that are communicatively coupled to one another using bidirectional, half-duplex links. The network has a logical first channel over which data is propagated along the network in a first direction and a logical second channel over which data is propagated along the network in a second direction. For a given period of time, at least one of the plurality of nodes is scheduled to be a transmitting node that transmits data on both the first channel and the second channel. A first subset of the nodes not scheduled to transmit during the period are scheduled to relay data received from the first channel along the first channel. A second subset of the nodes not scheduled to transmit during the period are scheduled to relay data received from the second channel along the second channel.

Abstract: In one embodiment, a system comprises a plurality of nodes that are communicatively coupled to one another. Each of the plurality of nodes, in the absence of any faults, is communicatively coupled to at least a first neighbor node and a first neighbor's neighbor node and a second neighbor node and a second neighbor's neighbor node. When at least a first clique and a second clique exist within the plurality of nodes and a first node included in the first clique successfully receives a synchronization message associated with the second clique from the first neighbor node of the first node and the first neighbor's neighbor node of the first node, the first node does the following. The first node defects to the second clique and synchronizes to the synchronization message. The first node also communicates a join message to at least the second neighbor node of the first node and the second neighbor's neighbor node of the first node.

Abstract: A communication device comprises a port via which the communication device is operable to communicate over a communication channel; command hardware operable to output a controlled signal over the communication channel; monitor hardware operable to monitor the controlled signal and output a controlling signal to block propagation of the controlled signal if a fault is identified in the controlled signal; and signal blocking circuitry coupled to a transmission path of the controlled signal and to a transmission path of the controlling signal; wherein, when the controlled signal is to be blocked, the signal blocking circuitry applies the controlling signal to the controlled signal such that a receiver at one end of the transmission path of the controlled signal identifies the controlled signal as a faulty signal; and wherein, when the controlled signal is not being blocked, the controlled signal is unimpeded by the signal blocking circuitry.

Abstract: In one embodiment, a node comprises an interface to communicatively couple the node to a first channel. The first channel communicatively couples the node to a first neighbor node and a first neighbor's neighbor node in a first direction. When the node is operating in an unsynchronized mode: the node relays, along the first channel, for a relay period, data received from the first neighbor node that was sourced from that first neighbor node and, after relaying the data received from the first neighbor node that was sourced from that first neighbor node and for a block period, the node blocks data received from the first neighbor while the node relays, along the first channel, data received from the first neighbor's neighbor node.

Abstract: A distributed control system comprises a first network section comprising one or more control nodes containing control logic operable to perform control function computations; a second network section, wherein the second network section comprises; a plurality of additional nodes responsive to the one or more control nodes in the first network section, each of the plurality of additional nodes communicatively coupled to two neighbor nodes and to two skip nodes using a plurality of links; first and second gateway interfaces each coupled to the first and second network sections and each operable to interface the first network section to the second network section; wherein the first network section is operable to communicate signals using a first communication protocol; and wherein the plurality of nodes in the second network section are operable to communicate signals over the plurality of links using a second communication protocol that is different from the first communication protocol.

Abstract: A method for arbitrating access to a time slot in a time division multiple access network in an asynchronous hub with a bus guardian is provided. The method including receiving signals from competing nodes claiming access to the same time slot at the bus guardian of the asynchronous hub, selecting one of the nodes based on a priority scheme, and relaying a message from the selected node and blocking the message from the non-selected node.

Abstract: In one embodiment, a method is performed at a node. The method comprises outputting, from a rate-changeable clock included at the node, a first clock signal having a clock rate. The method further comprises generating a second clock signal from the first clock signal for use in determining when transmissions in a network are to start. The method further comprises sending and receiving data from the node using the first clock signal as a line encoding/decoding clock. The method further comprises making relative clock-rate measurements at the node based on transmissions received at the node and using the relative clock-rate measurements to adjust the clock rate of the rate-changeable clock. The method further comprises making clock-state adjustments to the second clock signal.

Abstract: A communication device comprises first and second circuits to implement a plurality of ports via which the communicative device is operable to communicate over a plurality of communication channels. For each of the plurality of ports, the communication device comprises: command hardware that includes a first transmitter to transmit data over a respective one of the plurality of channels and a first receiver to receive data from the respective one of the plurality of channels; and monitor hardware that includes a second receiver coupled to the first transmitter and a third receiver coupled to the respective one of the plurality of channels. The first circuit comprises the command hardware for a first subset of the plurality of ports. The second circuit comprises the monitor hardware for the first subset of the plurality of ports and the command hardware for a second subset of the plurality of ports.

Abstract: One embodiment comprises a network that includes a plurality of bi-directional links and a plurality of nodes. Each node is communicatively coupled to two neighbor nodes and to two skip nodes using the plurality of bi-directional links. Three neighboring nodes of the plurality of nodes form a triple modular redundant (TMR) set having a first end node, a second end node, and a center node, the first end node configured to transmit output data in a first direction and the second end node configured to transmit output data in a second direction.