A data communication device for use either as an interface between a data processing device and a transmission medium of a CSMA/CD network or as a repeater between a CSMA/CD network and an additional data communication network which shares a transmission medium with the CSMA/CD network, sends an obstruction signal towards the CSMA/CD network when an input buffer tends to overflow on storing an input data packet for delivery to the data processing device or for transmission towards the additional...

An adaptive congestion control device (600) and method minimize congestion using independent congestion level indicators. The invention allows efficient recovery for an integrated packet network that becomes congested and allows a user to utilize the network on a space-available basis when capacity is available.

An apparatus for monitoring and controlling a complex construction installation from a local or remote location. Each of the functional components of the installation have slave processors associated therewith. The slave processors are coupled to a master and additional processing unit. A communication system for each of the functional components connects all of the functional elements within the components and enables a two way data communication between the master and additional processors and...

A packet communication system which communicates various communication information such as voice, data or images in the form of a packet and which provides a transmission quality which satisfies both of high instantaneousness and low discard properties and a method of controlling the system. A counter counts the respective numbers of stays of packets in priority-classified buffers. The percentages of output of packets from the respective buffers and both of the percentages of output of packets f...

For monitoring a transmission system comprising a number of asynchronously operating channels through which data cells can be transmitted, variable values are stored which, on arrival of a data cell, are altered by an alteration algorithm in accordance with data cell traffic and are then processed by an evaluation algorithm to produce an evaluation signal. Such evaluation signals are processed by a combination algorithm to produce a control signal. A data cell is or is not, transmitted, dependin...

This invention is a method of and apparatus for implementing a service scheduling discipline to enable data devices efficient access to data resources. According to the invention, information identifying one or more data packets of each data batch is sorted into one or more of a plurality (N) of epoch queues, such that for each data batch, no information identifying more than a predetermined number (P) of data packets from a particular channel is inputted into each epoch queue. Each epoch queue ...

A broadcast data transmission station for use in a data transmission system. The station includes a traffic amount counter for computing the amount of broadcast data present on a transmission line during a unit time period. A comparator indicates whether the traffic amount computed by the traffic amount counter has reached a predetermined limit. If the limit has not been reached, a transmission execution circuit allows the broadcast data to be sent on the transmission line. If the limit has been...

A flow control system is disclosed, for a transmitting node and a receiving node. The transmitting node and the receiving node are linked together through multiple connections or virtual circuits. The receiving node includes a connection specific pool of buffers for receiving data transmission units from the transmitting node over each specific connection, and a common pool of buffers for storing data transmission units received from the transmitting node over any of the connections between the ...

A flow control system is disclosed, for a transmitting node and a receiving node. The transmitting node and the receiving node are linked together through multiple connections or virtual circuits. A flow control circuit in the transmitting node limits the number of data transmission units transmitted from the transmitting station, and not yet copied out of the receive buffers in the receiving node, to the total number of receive buffers in the receiving node. The flow control circuit in the tran...

A method and apparatus for transmitting document data enabling transfer of document data over a communication path assigned the highest possible priority among a plurality of communication paths. First, an attempt is made to transfer document data over the highest-priority communication path. If the attempt has failed, the document data are transferred over a communication path which is lower in priority than the highest-priority communication path. After information for one page of text data ha...