Abstract: In a transmission system in which redundant message cells are forwarded via redundant transmission paths according to the Asynchronous Transfer Mode, a transmission path is blocked after the occurrence of a small number of errors in the sequence of the transmitted message cells, while for an admission of a transmission path a large number of successive message cells without error in the sequence is required.

Abstract: A connection admission control system for the link of an ATM switch generally includes a system for accepting a proposed call if the tangent effective bandwidth, a conservative approximation for the bandwidth, of the proposed call when added to the sum of the tangent effective bandwidths of all other calls being handled by that link are less than the capacity of the link is less than the capacity of the link. The proposed call may also be accepted if the zero-loss effective bandwidth for the proposed call when added to the sum of the zero-loss effective bandwidths of all other calls being handled by that link is less than the capacity of the link. The tangent effective bandwidths and zero-loss effective bandwidths are calculated off of the switch by a processor and stored in a table at the switch. When a call request is received it is placed into a connection class, and the tangent effective bandwidth and zero-loss effective bandwidth relating to that connection class is found in the table.

Abstract: An ATM communication system has an ATM switch having a plurality of input ports and a plurality of output ports, each of the input ports being fed from an input port server and each of the output ports being arranged to feed an output port server. The input port servers each have a plurality of buffer stores, one for each of the output ports to which output port data is transmitted through the switch. Each buffer store in the input port servers is arranged to interrogate the output port server with which it communicates by a bandwidth request before the transmission of data. This determines whether output port server data handling capacity is available, whereby ATM switch operation during periods of peak traffic is facilitated. The system includes a queuing arrangement for bandwidth requests received during periods when there is no available bandwidth capacity, the arrangement being such that requests are released in a predetermined order when capacity becomes available.

Abstract: A modified leaky-bucket method for a message transmission system wherein a message cell stream is asynchronously transmitted, this message cell stream carrying message cells for a plurality of virtual connections with a broad range of possible message cell rates, the message cell rate for every virtual connection is being monitored and limited according to a leaky-bucket method, the shortest allowable, timing between two message cells belonging to the same virtual connection being represented by the quotient of two numbers.

Abstract: An ATM signal processor system for processing ATM data cells which in combination define a data package wherein the last cell of a package is characterized by an identifying code. The cells of different data packages are multiplexed to provide a serial data stream. A server and a buffer store via which the server is fed with the serial data stream are provided. The buffer store has a threshold capacity beyond which cells are discarded. A discarded cell identifier/rejecter serves to identify and store the identity of a data package with which a discarded cell is associated so as to be set thereafter to reject subsequently received cells with the same data package identity until being reset upon receipt of the last cell of the package as indicated by its characteristic identifying code.

Abstract: A method for a transmission line via which message cells of a plurality of virtual connections having separately defined transmission bit rates asynchronously transmitted, wherein, depending on the transmission bit rate declared for a connection and depending on the chronological spacing of message cells belonging to the same connection that are intended for forwarding, a time slot in which a message cell is to be forwarded is identified for every message cell, whereby a message cell--depending on the length of the time slot calculated for it--either is discarded or is stored for forwarding in the respective, calculated or in a following time slot.