Abstract: An access control system for a computing environment in which a number of processing nodes are interconnected to one another via an interconnection system. Multiple program applications, each made up of a number of application components, are installed in the environment, such that their components may be distributed among the various processing nodes of the platform. A set of rules is established, indicating allowed inter-node communications between the application components, and those rules are mapped onto a set of logic in the platform. The logic may be embodied in various forms, such as packet-filtering logic in a network interconnect switch, or firewall logic in a processing node. In turn, when an application component on one node attempts to communication with another application component on another node, a determination can be made whether the communication is allowed and, if the communication is not allowed, the communication can be blocked.

Abstract: The present invention is a method and apparatus for providing a general-purpose, multifunction, individually addressable, full-bandwidth bi-directional communication device with built-in Authentication, Authorization, and Accounting (AAA) capabilities that connects a home or business user with ATM and other switched broadband digital networks in a convenient, adaptable, extensible manner at reasonable cost. The device supports a Document Services Architecture (DSA) and, in particular, supports agent-based communications (including interaction with an Agent Instance Service) to ensure well-behaved communications and fair allocation of network resources among users. The device can be used in a heterogeneous environment and with different types of networks and protocols. The full-bandwidth bi-directional communication and built-in AAA capabilities of the device distinguish it from other "set-top boxes.

Abstract: Access to a limited bandwidth switching network of an ATM (Asynchronous Transfer Mode) switch is scheduled using a reservation ring. In general, a limited bandwidth switching network is unable to generate all possible one-to-one input to output channel mappings in a single switch cycle. The limited bandwidth switching network includes one or more routing channels for routing at most B data packets each switch cycle between the input channels and output channels, where the number of data packets B is less than the aggregate output bandwidth that can be directed at the routing channels. Arbitration requests make two passes around the reservation ring each arbitration cycle. Output channel contention is settled during the first pass around the reservation ring. Contention for limited switching network bandwidth is settled during the second pass around the reservation ring.

Abstract: A self-arbitrating and self-routing ATM (Asynchronous Transfer Mode) switch has a switching fabric consisting of rows and columns of logic groups. The rows of logic groups have addressing logic for routing data packets received at input ports to the columns of logic groups. Arbitration logic in each of the columns of logic groups route data packets received from the addressing logic to their specified output ports. The arbitration logic forming each column of logic groups resolves conflicts between data packets contending for an identical output port. Additional logic in each column of logic groups signals input ports when data packets are successfully received by their specified output ports. Data packets which lose arbitration during a switch cycle are assigned a higher priority and retransmitted to the switching fabric during the next switch cycle.

Abstract: Ports of an ATM (Asynchronous Transfer Mode) switch are consolidated into cluster modules to increase the aggregate throughput of the switch. Packets are routed between cluster modules using an intercluster switching network. The intercluster switching network includes a plurality of input channels and output channels. During a switch cycle, a maximum of "K" packets are delivered to each of the output channels of the intercluster switching network. This maximum of "K" packets is a speedup per cluster module that is shared between ports of each cluster module. Consequently, each output port of a cluster module operates with a peak speedup of up to "K" packets per switch cycle thereby increasing the aggregate throughput of the switch.

Abstract: A method controls multicast cell access to a switching network with a reservation ring in an ATM (Asynchronous Transfer Mode) switch. The switching network distributes the multicast cell in one or more passes from an input channel to one or more output channels of the switch during a switch cycle. An arbitration session for a multicast cell begins by submitting an arbitration request identifying a set of destination output channels to the reservation ring. During an arbitration cycle, the output channels in the set of destination output channels are arbitrated for over the reservation ring. The arbitration request is reissued during later arbitration cycles until access to each of the destination output channels in the set of output channels is granted.

Abstract: A non-blocking switching network for routing packets from a plurality of inputs to a plurality of outputs includes a reservation ring mechanism for resolving conflicts among inputs contending for access to specified ones of said outputs. This reservation ring performs a sequence of step and compare operations in top-to-bottom ring-like order during at least one arbitration cycle for granting contending inputs access to said specified outputs in a top-to-bottom order that is also consistent with the order required by self-clocked weighted fair queueing or, alternatively, virtual clock, with up to a maximum permissible plural number of contenders being given access to such an output on each of the arbitration cycles.

Abstract: An expandable, self routing switching fabric routes data packets in an ATM switch. A crosspoint array of state machines disposed at internal intersections of input ports and output ports have predetermined identities representative of the output ports and include a comparator for identifying an address header of each data packet with the state machine identity. When a match occurs, the state machine is set active/connected and when a non-match occurs, the state machine is set not-active/disconnected. A circuit through the fabric is set by connection between an input port through an active/connected state machine to a desired output port. The predetermined identity of each state machine comprises a hard wired bit sequence common to the column including the state machines.

Abstract: A crossbar switching fabric for routing data packets in an ATM switch. A logic unit associated with a reservation ring in an ATM switch intercepts data exiting a selected evaluator of the reservation ring, and processes this data to set-up a crossbar switching fabric for routing data packets of the ATM switch. The set-up data may be passed to the crossbar switching fabric upon each clock cycle thereby not incurring any pipeline processing delays. Alternatively, the set-up data is accumulated and stored in the logic unit until the completion of an arbitration session, whereafter it is sent to the crossbar. In place of the logic unit a plurality of registers may be added to each of the evaluators of the reservation ring. The registers in turn interconnected to each other in a shift register arrangement to provide the set-up data to the crossbar fabric.

Abstract: A switching network having a sorting network followed by a plurality of routing networks for routing packets from a plurality of inputs to a plurality of outputs in accordance with destination addresses specified by the packets includes a reservation ring mechanism for resolving conflicts among inputs contending for access to identical outputs. This reservation ring mechanism performs a sequence of step and compare operations in top-to-bottom ring-like order during one or more arbitration cycles for granting contending inputs access to the outputs for which those inputs are contending in top-to-bottom order. Each of the routing networks can route packets from any input to any output, so up to k packets are routed to each output during each arbitration cycle, where k equals the number of routing networks that are employed.

Abstract: A non-blocking, self-routing switch having a sorting network followed by a plurality of routing networks for routing packets from a plurality of inputs to a plurality of outputs includes a reservation ring mechanism for resolving conflicts among inputs contending for access to identical outputs. This reservation ring mechanism shifts a reservation vector in top-to-bottom ring-like order during at least one arbitration cycle for granting contending inputs access to identical outputs in top-to-bottom order, with a maximum permissible plural number of contenders being given access to such an output on each of said arbitration cycles whenever there still are at least said plural number of contenders in contention for that particular output. The reservation vector is composed of a plurality of bits for registering reservations for each of the outputs.

Abstract: A switch having a non-blocking, self-routing switching fabric for routing packets from the input ports to the output ports of the switching fabric in accordance with a virtual circuit designation and an output port address that is carried by each packet requires that the output port address for each of the packets being specified by the first few bits of a switch header that is appended to said packet. The switching fabric advantageously is composed of a plurality of parallel connected single bit wide sorting networks followed by a plurality of parallel connected routing networks for providing multi-bit wide data paths between its input ports and its output ports. Moreover, the switching fabric is constructed to have one multi-bit wide sorting network and a plurality of multi-bit wide routing networks for giving plural input ports simultaneous access to identical output ports.

Abstract: In an asynchronous transfer mode (ATM) switch having a Batcher sorting network followed by a plurality of banyan routing networks for switching packets from trunk grouped inputs to non-trunk grouped outputs via virtual circuits, order is maintained among the packets that are switched to the outputs by appending a bit, called the "stopper ID," to the destination address of each packet. This bit is computed on an input-by-input basis by a reservation ring that gives all inputs that are contending for access to any given output fair, round robin access to that output depending upon the round robin position of the particular input, so it is a valid sort key for preserving cell order. However, when packets are switched from trunk grouped inputs to trunk grouped outputs, a secondary sort key is employed for preserving the ordering of packets that are transferred via the same virtual circuit.

Abstract: A switch having a non-blocking, self-routing switching fabric for routing packets from input sources to output destinations on virtual circuits specified by such packets, has a multicast mechanism for routing multicast packets from any one of the sources to copy groups composed of multiple ones of the destinations. This multicast mechanism includes a copy network that is coupled to receive the multicast packets from the switching fabric after the packets have made at least one pass through the switching fabric, and this copy network is configured for making separate copies of each of the packets for each member of the copy group to which the packet is addressed and for applying the copies to said switching fabric, such that the copies are rerouted by the switching fabric to the respective members of the specified copy group.