Abstract: In a network of a topology of a loop and a bus, occurrence of a failure is detected and a location of the failure is specified. Occurrence of the failure is detected by detecting that a specific signal pattern to be received at regular time intervals within a fixed time period is not received. A node which has detected occurrence of the failure transmits or receives a specifying signal among the nodes, and decide whether or not the failure has occurred adjacently to itself. A packet indicating a decided location of the failure is transmitted or received among nodes, and thereby respective nodes specify the location of the failure. When the failure has occurred at the master node, a node having a smallest node ID after waiting time according to the node ID operates as the alternative master node.

Abstract: There is provided a transmission system which realizes more flexible resource allocation. A resource management means 12, upon receipt of a resource allocation request including a minimum bandwidth and a maximum bandwidth, reduces allocated resources stored in an allocated-resource request table 13 to the corresponding minimum bandwidths. As such, the request is accepted with higher probability. When releasing an allocated resource, the resource management means 12 increases the allocated-resources of the allocated-resource requests to bandwidths within a range of the corresponding maximum bandwidths. Accordingly, the resources are utilized more effectively. When releasing the resource, the resource management means 12 notifies, by broadcast, all the communication apparatuses that free resources are increased. Thus, for the communication apparatus whose request has been rejected, the resource is allocatable.

Abstract: A transmitting system which comprises a transmission line, a transmitting apparatus connected to the transmission line, and a receiving apparatus connected to the transmission line, and transmits data between the transmitting apparatus and the receiving apparatus, wherein the transmitting apparatus comprises packet compressing means which receives input data comprising plural packets having identifiers as an input, identifies packets to be discarded and effective packets according to the identifiers, and outputs compression information indicating the number of continuously discarded packets and the effective packets to the transmission line, and the receiving apparatus comprises packet restoring means which receives the compression information and the effective packets which have been output from the transmitting apparatus, generates ineffective, packets which are as many as the discarded packets, and outputs the ineffective packets and the effective packets.

Abstract: A network system includes at least one transmitting apparatus connected to a network for outputting packets containing data to the network and at least one receiving apparatus connected to the network for receiving from the network the packets that have been output from the transmitting apparatuses, the transmitting apparatuses and the receiving apparatuses making up plural transmitting/receiving systems. The network system includes a data packet monitor for monitoring the packets transmitted through the network and detecting the amount of data in the packets to be used in a specified transmitting/receiving system; and band manager for determining a bandwidth on the network to be used by the specified transmitting/receiving system, based on the amount of data in the packets that is detected by the data packet monitor.