International Business Machines Corporation

Ange Aznar

Daniel Orsatti

Dominique Rigal

Fabrice Jean Verplanken

Jean L Calvignac

Bruno Rousseau

Jean-Claude Zunino

Jose Iruela

Claude Basso

Jean-Luc Frenoy

Mathieu Michel Girard

Luc Torres

Jose Iruella

In an ATM cell-relay network usually comprising several switching nodes a method enabling remote surveillance of any entry port to any switching node of the network. The method first assumes that a path is set up from the entry port to a remote observation point. Then, all cells of the incoming traffic, entering entry port to be watched, are duplicated and marked. After which they are transported, unaltered, following the path, up to the observation point. The invention permits that any entry port of an ATM network, that may well span over large geographic areas, be conveniently observable and analyzed transparently i.e., without disturbing users traffic, from a remote location so as network can be maintained and run trouble free.

System and method for enabling remote surveillance of ATM network switching node ports

A method and system for injecting/extracting a control cell into/from a data connection transmitted from a source switching node to a destination switching node of an Asynchronous Transfer Mode (ATM) network. The injecting method consists in adding to the ATM cell a switch routing label (SRL) and a protocol engine correlator (PEC) by the control point of the injection switching node before injecting the cell into the connection. The extracting method consists in setting a control flag in the control block of the incoming cell if this cell includes an extraction condition indicating that it is a control cell to be extracted, and adding to the control cell a switch routing label corresponding to the control point (CP SRL) and a reserved static protocol engine correlator (SPEC).

Method of injecting/extracting control cells in an asynchronous transfer mode (ATM) network

A system and method for merging multiple connections that share a same class of service into a single virtual circuit (VC) in an Asynchronous Transfer Mode (ATM) network. A queuing apparatus includes multiple connection queues for each of the connections, and further includes a scheduled queue corresponding to a particular class of service, wherein contents of the connection queues are transferred into the scheduled queue before being transmitted on the VC. A reassembly queue control block (RQCB) defines a chain of buffer control blocks for the connection queues. Each buffer control block corresponds to a cell belonging to a packet of a particular connection and includes a next buffer address and a lock bit. The chain of buffer control blocks is transferred to a scheduled queue control block (SQCB) in response the lock bit indicating a last packet cell.

Enqueuing apparatus for asynchronous transfer mode (ATM) virtual circuit merging

A method and system for enforcing a transmission control parameter for a virtual connection comprising multiple cells within an input port. The virtual connection has a nominal inter-cell arrival rate increment. Each of the cells are associated with a theoretical arrival time and an early arrival limit, wherein a difference of the early arrival limit from said theoretical arrival time delineates a lower boundary of a good zone, while the theoretical arrival time minus the sum of the early arrival limit and the nominal inter-cell arrival rate increment delineates an upper boundary of the good zone. The method includes determining an actual arrival time for an incoming cell from the cells that make up the virtual connection. Next, the actual arrival time is compared to the upper boundary and the lower boundary to determine whether or not the actual arrival time falls within the good zone. In response to determining that the actual arrival time falls within the good zone, the incoming cell is identified as conforming to the transmission control parameter. The method and system of the invention allow to use a finite counter for measuring elapsed time at entry ports of ATM switching nodes, a mandatory feature in order to enforce policing, while avoiding having to manage the overflows of the counter.

Method and apparatus for policing cell-based traffic

A system and method for selecting one port among multiple output ports having various transmission rates attached to an output adapter of a switching node in a data transmission network and enabling it to transmit its data over the network. The system of the present invention includes a storage device that contains a list of identification codes for the ports. The identification code list is arranged in a prioritized order from the port having the highest transmission rate to the port having the lowest transmission rate. The system further includes port service request means that generate a service request signal for each port, wherein the service request signal has a frequency corresponding to the transmission rate of the object port. Port selection means are utilized to, in response to said identification codes and said service request signal, select a requesting port having a highest priority according to its identification code and enabling the selected port to transmit data over the date transmission network.

System and method for selecting multi-rate ports in a data transmission network

The invention discloses a method and an apparatus for use in high speed networks such as Asynchronous Transfer Mode (ATM) networks providing support for processing multipriority data flows at media speed, the major constraint being to share the storage and the ALU between all the tasks. The invention consists first in grouping the tasks in processes and the processes in set of processes all organized in decreasing order of their priority ; `on the fly`interruption of a lower priority process/set of processes by a higher priority process/set of processes is possible as well as reuse of the shared resources during task void states inactive in a process or between processes. In the preferred embodiment of the invention, the support of the reserved bandwidth and non reserved bandwidth ATM services data flows requires two different groups of processes, the highest priority being for the group of processes serving the reserved bandwidth service. With the principle of the invention when used in network equipment the media speed is sustained and many different network traffics can be simultaneously supported. The apparatus implementing the solution of the invention, allowing sharing of resources saves place and costa by the improved reduced number of sophisticated hardware components such as static memories and programmable logic circuits.

Method and apparatus to share resources while processing multiple

An ATM switch includes one or more adapters having input ports and/or output ports and a switching fabric for switching Asynchronous Transfer Mode (ATM) cells received at the input ports to the output ports. To maintain switch throughput, cells are categorized either as real time (high priority) or non-real time (lower priority) cells. High priority cells are processed using a first set of cell processing logic at a rate at least equal to the rate at which the cells are received on the input ports. Lower priority cells are processed using a second set of cell processing logic only when no high priority cells are being processed.

Method and apparatus for priority level queueing in processing ATM cell

A multicasting apparatus and method for an Asynchronous Transfer Mode (ATM) switch is described, which uses a single target port (TP) vector attached to each outgoing ATM cell. The target port vector contains identifiers of each port to which the cell has to be transmitted. After transmission of the cell, the identifier relating to respective target port is erased from the TP vector. Hence the TP vector contains only identifiers of target port to which the cell has not yet been transmitted. When the TP vector contains no identifiers, the storage location at which the ATM cell is stored during the transmission, is freed for another cell. Unicast and multicast traffic are treated identically.

ATM cell multicasting method and apparatus

The techniques required to switch an ATM cell between an input adapter and an output adapter are enhanced by performing two look-up operations. The first look-up operation is performed in the input adapter which receives the cell to be switched. The first look-up operation retrieve the address of the target output port and a connection control block. The second look-up operation is performed in the target output adapter and makes use of the results of the input adapter search to retrieve the information need to complete the transfer of the cell to the target output port.

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Ange Aznar