Abstract: The total implementation complexity of packet schedulers which aim at approximating the Generalized Processor Sharing (GPS) policy is the combination of the complexity of their system-potential function and the complexity involved in sorting the timestamps in order to select the packet with minimum timestamp for transmission. Given that several scheduling algorithms which use a system-potential function of O(1) complexity have been introduced (among them, the Minimum-Delay Self-Clocked Fair Queuing (MD-SCFQ) algorithm achieves optimal delay and excellent fairness properties), the major contribution to the total complexity comes from the task of sorting the timestamps every time a packet is transmitted or received, which is common to all GPS-related schedulers.

Abstract: The adaptive sequential pattern memory search technique only examines the contents of a subset of the total number of memory locations in each search for information representative of a character string. The subset includes a plurality of storage locations and each examination is performed in one concurrent read operation. If the character string is not matched, the memory must be updated to store information representative of the unmatched string. This updating process selects one location from the subset for storing this representative information. Advantageously, an indicator of when each stored representative information last matched a character string is maintained and utilized in the selection process. In addition, to avoid operational errors associated with outputting invalid information from the "child" of a previously discarded "parent", an indication of the time each stored entry is created is utilized to remove such invalid information as it is detected in the updating process.

Abstract: Multicasting of an ingress cell received at one of a plurality of input ports is provided through a multistage switching network to one or more of a plurality of output ports. An ingress cell including a data payload and information identifying output ports of the network is received at one of the input ports of a first stage of the network. A determination is made of the minimum number of first output ports of the first stage of the network to which a single copy of the ingress cell is to be outputted to enable the ingress cell to reach all of the identified output ports. The single copy of the ingress cell is then routed to the minimum number of first output ports of the first stage of the network.

Abstract: Multicasting of an ingress cell received at one of a plurality of input ports is provided through a multistage network to a plurality of output ports. The received ingress cell at a first input port includes a data payload and information identifying one or more routing queues to which a single copy of the data payload is to be outputted. A backpressure queue assignment is identified for the first ingress cell, the backpressure queue assignment identifying a backpressure indicator indicative of the congestion level at at least one routing queue of a subsequent stage. Using the backpressure indicator, it is determined if the first ingress cell is to be outputted from one or more of the routing queues. Thereafter, the first ingress cell is outputted from one or more of the routing queues when the congestion level is below or equal to a first threshold.

Abstract: Multicasting of an ingress cell received at one of a plurality of input ports is provided through a switch network to one or more of a plurality of output ports. The received ingress cell includes a data payload and a bitmap segment identifying the one or more output ports to which the data payload is to be outputted. The data payload is stored in an available cell buffer; associated with each cell buffer is a reference counter for storing a number equal to the number of ports to which that ingress cell is to be outputted. The bitmap segment is used to identify output ports to which the data payload is to be delivered, and a plurality of linked list queues in the memory, one for each of the output ports, is established. The bitmap segment is interpreted to identify output ports to which the data payload is to be delivered and an entry is made into the associated linked list output queue.

Abstract: Interchange of data between two way loops and a data trunk is provided by way of channel units, submultiplexer/demultiplexers and a common multiplexer/demultiplexer. Submultiplexers have five, 10 or 20 ports, creating time frames with corresponding numbers of time slots, all of equal duration. The channel units, which terminate 9.6, 4.8 or 2.4 Kbs data subscribers, assemble the incoming data into bytes, repeat each byte five, 10 or 20 times, respectively, and align each successive one of the repeated bytes with successive time slots. Any port of a five port submultiplexer can be connected to any 9.6, 4.8 or 2.4 channel unit. Similarly, any port of a ten port submultiplexer can be connected to any 4.8 or 2.4 channel unit and any port of a twenty port submultiplexer can be connected to any 2.4 channel unit. The outputs of all submultiplexers are interleaved by the common multiplexer and applied to the trunk.