Abstract: A method is described for sending frames of data from at least two sending nodes via one or more forwarding nodes to one receiving node in an ATM network. Each frame of data is partitioned into cells and includes a VPI field and a VCI field. The sending nodes include a first label into the VPI field of each of the cells representing an identification of the routing of the cell. Furthermore, the sending nodes include a second label into the VCI field of each of the cells representing an identification of the source of the cell. The forwarding node swaps the first and the second label according to a swapping table. With respect to the second label, the forwarding node enters the swapping table in the column of the output labels and reads the corresponding input label.

Abstract: The present invention is related to a method for allocating pending requests for data packet transmission at a number of inputs to a number of outputs of a switching system in successive time slots, wherein according to a matching method the allocation of the pending requests is optimized, wherein the matching method includes a number of steps for incrementally allocating the requests, wherein as a result of each step a matching information is provided, wherein in each time slot a request information is provided, the request information indicating the data packets at the inputs requesting transmission to respective outputs, the matching method comprising the steps of providing a first request information in a first time slot, performing a first step in the first time slot depending on the first request information to obtain a first matching information; providing a last request information in a last time slot successive the first time slot; performing a last step in the last time slot depending on the last re

Abstract: Methods for controlling a data packet flow through a switch having first, second and third stage switch modules. Each switch module has a number of data inputs, a number of data outputs, and a data packet buffer. The data outputs of the first stage switch modules are connected to data inputs of the second stage switch modules, and data outputs of the second stage switch modules are connected to the data inputs of the third stage switch modules. A data packet received at one of the first stage switch modules is forwarded to a specific data output of one of the third stage switch modules.

Abstract: A method and system for managing asynchronous transfer mode (ATM) traffic in a computer system is disclosed. The computer system is used in sending, receiving, or sending and receiving a plurality of ATM flows. Each ATM flow has a plurality of ATM cells, a minimum ATM bandwidth guarantee, and a maximum ATM bandwidth. The method and system include determining whether excess bandwidth exists for the ATM flows. The method and system also include gracefully increasing a portion of the ATM cells transmitted for each ATM flow during periods of excess bandwidth. The portion of the ATM cells transmitted is not more than the maximum ATM bandwidth limit. If an ATM flow presents a sufficient offered load, the portion of the ATM cells transmitted in the flow is not less than a minimum ATM bandwidth guarantee.

Abstract: A method for constructing the set of optimal complex node representations of a PNNI peer group based on a restrictive cost database (e.g. a cost matrix) associated with the border nodes. The resulting set of complex node representations is the optimal in that it contains all the possible complex node representations that use the minimum possible number of exception bypasses.

Abstract: Systems involving generation of a complex node representation of a PNNI peer group are provided. Use is made of a set of restrictive costs, such as a transition matrix, defining the restrictive costs of paths between pairs of border nodes of the peer group. The complex node representation generation method is based on the group evolution process of the logical group representation of a peer group, and use is also made of the spanning tree representation of a network. Complex node representations generated by the disclosed methods are optimal in that they contain the minimum possible number of exception bypasses.

Abstract: A method for deriving a set of efficient path costs for a group of nodes comprising a source node and a plurality of destination nodes in a data communications networks, wherein the path costs for paths between nodes in the group are defined in the network and each path cost comprises a restrictive cost and an additive cost, comprises iteratively identifying the paths of higher bandwidth first and, when two or more paths of equal bandwidth are encountered, selecting the path having a lower transit delay associated therewith.

Abstract: Methods and apparatus are provided for controlling the clustering of nodes which implement a cluster-based routing protocol in a data communications network system where the system comprises a plurality of such nodes which are interconnectable to form a plurality of ad hoc networks. For each node which is a member of a cluster, cluster control information (CCMs) is maintained, this cluster control information being dependent on the size of at least the cluster of which that node is a member. On connection of two nodes which are members of two respective clusters, each of the two nodes transmits its cluster control information to the other node, and then determines whether a clustering condition is satisfied. In each node, the clustering condition is dependent on the cluster control information maintained for that node and the cluster control information received from the other node. In each node, if the clustering condition is satisfied, the node then communicates a clustering agreement to the other node.

Abstract: Systems involving generation of a complex node representation of a PNNI peer group are provided. Use is made of a set of restrictive costs, such as a transition matrix, defining the restrictive costs of paths between pairs of border nodes of the peer group. The complex node representation generation method is based on the group evolution process of the logical group representation of a peer group, and use is also made of the spanning tree representation of a network. Complex node representations generated by the disclosed methods are optimal in that they contain the minimum possible number of exception bypasses.

Abstract: A flow control method is practiced in a first node in a computer network having one or more upstream nodes, each of which can provide data cells to the first node over a connection. Cells are transmitted over a connection during an established transmission period for that connection and at a data rate not exceeding a peak data rate. To determine whether a buffer is sufficient during a given time period starting at the current time, the potential buffer requirements during that time period are established as a function of the current buffer occupancy and the maximum number of cells which may be received during the given time period. If the potential buffer requirements exceed a predetermined buffer threshold, one or more stop signals is sent to upstream sources to limit the number of cells to be provided to the first node.

Abstract: An improved access control system for a memory system in which memory locations can be allocated to virtual output queues dedicated to output ports from the system. The virtual queues can be used to handle data of different priorities. Thresholds are defined for the occupancy of the overall memory and of each virtual queue. The access control system regulates the acceptance of data stored in input adapters by determining whether a back pressure situation exists for the data's target output adapter for the class of traffic to which the data belongs. A single-bit access-controlling back pressure signal is generated as a function of the occupancy level of either the overall memory or of the virtual queue defined for the target output adapter.

Abstract: Traffic congestion control is provided for a network node multiport switch capable of switching data packets of different priorities from input lines, via receive adapters, to output lines via transmit adapters. A spacing function is performed to limit the rate of data transfers through the switch in the absence of high priority data at the input lines and in the absence of a backpressure signal indicating the switch is congested at its output. If high priority data is detected or a backpressure signal has been generated, the data transfer rate is increased to deal with possible congestion.

Abstract: In a communication switch with input and output queueing, which handles different priority classes of traffic (e.g. video and audio applications with a high priority, and file transfers and e-mail as low priority traffic), the invention provides a timed shut-off mechanism at each input queue. This mechanism is activated when an input queue attempting to transmit low-priority traffic gets a backpressure signal. The mechanism interrupts further attempts to transmit low priority traffic for a predetermined period of T switching cell cycles. Hence, during the shut-off periods, the output queue is only used by the high priority traffic. Therefore, the performance of the high priority traffic is preserved.