Sgs-thomson Microelectronics Limited

Thomson-csf

Other

David Mouen Makoua

Pierre Dumas

Neil Richards

Marcello Coppola

Robert John Simpson

Pascal Moniot

Peter Thompson

Thierry Grenot

Michel Delattre

Marc Bavant

Colette Vivant

Yves Peligry

Vincent Cottignies

A process for detecting upstream congestion within an ATM switch. The switch includes several junctions linked together by a cross-connector. In each input junction, the number of incoming cells bound for a same specified output port of a junction are counted. Results of the count supplied by the input junctions are transferred to the output port. Results of the counts in the output junction are aggregated and a congestion is declared in the output port if the aggregate number of cells is greater than a specified threshold value.

Method for detecting upstream congestion in an ATM commutator with a switching system architecture and input memorization

An ATM routing switch has a buffer circuit for holding cells located on queues at output ports, the buffer having a first reserve buffer capacity for cells of a first type requiring integrity of cell transmission and a first designation for use in determining a permitted path through the network, a second reserve buffer capacity for cells of the first type having a second designation for use in determining a different permitted path in the network and a third reserve buffer capacity for cells of a second type accepting some loss of cells in transmission, flow control circuitry operating to limit input of cells of either the first or second type if predetermined thresholds for the first, second or third buffer capacities are reached.

ATM switch for routing different cell types

A method for the control of flows of digital information between a source and a destination linked by a network of intermediate switching entities consists in carrying out a control of flows without the participation of the intermediate switching entities in estimating a state of load of the intermediate switching entities and in estimating a state of congestion of the destination to control a number of cells that may be transmitted by the source to the destination. Application to the control of flows in an ATM switch.

Method for the control of flows of digital information

The present invention relates to a process for translating an ATM cell header for the routing thereof over a transmission highway of a communication network via an ATM switch, consisting in having the switch translate the pair (VPI, VCI) contained in the cell header, the first field VPI identifying a virtual path number and the second field VCI selecting a specified virtual channel within the virtual path.

Translation process for an ATM cell header

An ATM routing switch has a plurality of output ports for handling digital signal cells on a first type requiring integrity of cell transmission and a second type accepting some loss of cells in transmission, the output ports having control circuitry to provide a plurality of queues of cells at each output port, each queue comprising only cells of a single type while each port outputs a mixture of cells of both types on a common output path flow control indicators on incoming cells being used to inhibit output of cells along any path to a destination for which a flow control indicator has indicated congestion.

Congestion avoidance in an ATM switch

An ATM routing switch for bidirectional transmission of at least two types of cell, one type accepting variable bit rate of transmission and a second type accepting some loss of cells in transmission, includes first reserve buffer capacity for cells of the first type, a second reserve buffer capacity for cells of said second type and control circuitry for generating a flow control signal (FCT) if a predetermined threshold for the first buffer capacity is reached by input of cells of said first type, and discarding input cells of said second type if a predetermined threshold for said second buffer capacity has been reached by input of cells of said second type.

ATM switch

An ATM routing switch has a plurality of input and output ports and a buffer for holding a plurality of ATM cells, the cells being held in the buffer as a plurality of queues (F0-F7), each formed as a chained list of addresses with front and back pointers identifying ends of each queue.

Cell queue formation in an ATM switch

A network of ATM routing switches transmits digital signal cells of a first type requiring integrity of transmission and a second type accepting some loss in transmission, each switch has buffer circuitry. a plurality of output ports each having a plurality of queues of cells awaiting output, each output port having control circuitry to provide in an output frame control bits indicating the type of cell, a path identifier and the existence of flow congestion at the routing switch which it outputting the frame, thereby inhibiting transmission of further frames to that location until a frame is received from that location indicating that the congestion is cleared.

ATM switch flow control

An ATM routing switch for bidirectional transmission of digital signal cells some requiring integrity of transmission while others accept some loss of cells in transmission, has a plurality of output ports each handling a plurality of cell queues and control circuitry for decoding control bits in each input cell to determine which output port is to be used, which queue is required and whether flow congestions exists at the source of the input cell.

The method according to the invention consists of a first step in which messages sent by the sending subscriber are segmented into cells, a second step in which initial processing is carried out on each cell in order to space them uniformly at a minimum time interval at least equal to a determined resolution time, a third step in which a second processing succeeding the initial processing is carried out in order to space groups of cells with the same throughput by a minimum time interval determined as a function of the throughput allocated to each network subscriber, and a fourth step in which cells thus spaced are transmitted in a determined virtual circuit on the network.

Growing community of inventors

Nanterre, France

David Mouen Makoua