Abstract: A packet switch is configured for determining an equivalent bandwidth for use in GCAC. The equivalent bandwidth definition of the invention is derived by multiplying some known connection parameter such as, for example, a selected bandwidth value by a multiplier preferably computed and stored in look-up tables according to the invention. The appropriate multiplier for a given connection request associated with a call may then be found by accessing sets of the look-up tables based on one or more connection and/or network parameters. For each link in a path considered during GCAC, the product of the multiplication of the selected bandwidth value and the multiplier is then compared to the available bandwidth, AvCR, of the path links to determine if the path satisfies the connection request.

Abstract: A quality of service guarantee for voice and other delay sensitive transmissions within an Internet Protocol (IP) network is provided by identifying the IP network path utilized for IP packet transmission between source and destination edge devices and virtually provisioning IP network path bandwidth for priority voice traffic. Priority for voice packets and admission control of new voice calls (and other delay sensitive traffic) based on the remaining available capacity over the IP network path guarantees that high priority voice (and other delay sensitive traffic) meet stringent delay requirements. A Virtual Provisioning Server is utilized to maintain bandwidth capacity data for each path segment within the IP network and to forward the bandwidth capacity data to a Signaling Gateway. The Signaling Gateway determines whether to accept or reject an additional delay sensitive traffic component based upon available bandwidth capacity for an IP network path.

Abstract: A switch fabric for routing data has a switching stage configured between an input stage and an output stage. The input stage forwards the received data to the switching stage, which routes the data to the output stage, which transmits the data towards destinations. Each input device of the input stage transmits bids to the crossbar devices of the switching stage to request connections through the switching stage for routing the data to the output devices of the output stage. In one aspect, each crossbar device has (1) a bid arbitrator that determines whether to accept or reject each received bid, wherein, in response to a collision between multiple bids, the bid arbitrator accepts two or more of the colliding bids in a single time slot; and (2) memory for storing one or more accepted cells for the same output device, wherein the crossbar device can transmit grant signals for two or more accepted bids for the same output device in a single time slot.

Abstract: A switch fabric for routing data has a switching stage configured between an input stage and an output stage. The input stage forwards the received data to the switching stage, which routes the data to the output stage, which transmits the data towards destinations. In one aspect, at least one input port can be programmably configured to store data in two or more input routing queues that are associated with a single output port, and at least one output port can be programmably configured to receive data from two or more output routing queues that are associated with a single input port. In another aspect, the output stage transmits status information about the output stage to the input stage, which uses the status information to generate bids to request connections through the switching stage.

Abstract: A flow control method for available bit rate service in an asynchronous transfer mode network for detecting congestion in a switch and conveying congestion status information using resource management cells to the source which adjusts its flow rate accordingly. During detection of congestion in the switch the explicit rate field of the resource management cell is updated using a dynamic major reduction factor to improve transient queue-length performance.

Abstract: A method for consolidating backward resource management (BRM) cells in an available bit rate point-to-multipoint tree including a root, a plurality of leaves and a branch point interconnected between the root and the leaves. Initially, congestion information memory devices are reset. Then for each incoming return BRM cell to the branch point a determination is made whether the branch point has received a return BRM cell from a predetermined number of candidates in a candidate set of candidate-branches. If the branch point has not received a return BRM cell from the predetermined number of candidates in the candidate set then the congestion information from the incoming return BRM cell and the congestion information in the congestion information memory devices are consolidated in the congestion information memory devices.

Abstract: In a packet voice system, a dynamic build-out delay approach in a receiver during the duration of a call. In particular, the build-out delay is applied at least twice during the duration of the call. In one embodiment, a packet voice system includes an ATM Adaptation Layer Type 2 (AAL-2) and Service Specific Convergence Sublayer (SSCS) System. The receiver portion of the SSCS System recovers AAL-2 packets and plays back the compressed audio to a voice decoding element. In providing playback, the receiver applies the build-out delay at the start of each talk-spurt. The voice decoding element provides an uncompressed audio stream. In another embodiment, the receiver portion of the SSCS System applies the build-out delay at the start of the each talk-spurt as a function of the length of the previous silence interval.

Abstract: Buffer and bandwidth resources in an ATM switch having a multi-class queue capable of servicing one or more ATM service classes are dynamically allocated at each call setup and release request.

Abstract: In a packet voice system, discarding of a packet is performed as a function of previously discarded packets. In one embodiment, a packet voice system includes an ATM Adaptation Layer Type 2 (AAL2) and Service Specific Convergence Sublayer (SSCS) System. In this system, a transmission buffer stores AAL2 voice packets for transmission, each AAL2 voice packet comprising a sequence number, the values of which range from 0 to n−1, and a source identifier, k. When traffic congestion is detected, the transmitter portion of the SSCS System selectively discards one packet from a source k at the output of the transmission buffer if no packet from source k was dropped in either the last n−1 packets or over a predefined prior interval of time. Another embodiment of the invention discards packets at the input of the transmission buffer.

Abstract: A method for controlling data packet traffic flow over a bus interconnecting two or more nodes in a data communication system, each node having a unique address associated therewith and having a respective buffer memory for temporarily holding incoming data communicated thereto, each node further being capable of multicast sending of data packets over the bus to one or more nodes having respective addresses logically associated a unique address, the method comprising: checking current available buffer memory occupancy upon receipt of a data packet, the node being capable of outputting for transmission on the bus a first flow control indicator message when the data temporarily stored in the buffer memory is above a first buffer occupancy threshold associated with data of a first priority type, and a second flow control indicator message when the data temporarily stored in the buffer memory is above a second buffer occupancy threshold, the second buffer occupancy threshold being greater than the first occupancy

Abstract: An AAL2/SSCS packet voice system multiplexes various forms of voice-band traffic including voice packets, fax packets, and data packets into a virtual circuit (VC). This AAL2/SSCS packet voice system executes a dynamic call admission algorithm that takes into account call type in deciding whether to admit a new call to the VC. In particular, this approach takes into account different bandwidth needs for different call types. The AAL2/SSCS packet voice system also performs bit or block dropping on voice packets to mitigate the effects of traffic congestion. The bit or block dropping is done based on the packet queue fill value exceeding at least one queue threshold. Further, the AAL2/SSCS packet voice system also dynamically varies a queue threshold as a function of capacity.

Abstract: An improved flow control method for ABR service in an ATM network. In particular, a dual local/global ingress flow control method for ABR service in a distributed ingress queueing switch including a plurality of ingress buffer-pools, at least one shared buffer-pool and a plurality of egress buffer-pools. Utilization of the egress port of each shared buffer-pool is periodically measured and together with the current state of the global-ingress control forms the basis for toggling global-ingress control in an active/inactive state. Queue-length based flow control algorithms such as DMRCA are applied to each resource management cell for the egress subport queue and ingress flow queue through which the resource management cell passes to determine the egress and local-ingress congestion marking values, respectively, for the resource management cell.

Abstract: In a switch fabric environment, which includes a buffer, packet data of different class-types from different sources is received, stored in the buffer, processed and outputted to its intended destination. As the buffer fills up, transmission from some of the data sources is stopped to avoid dropping of packets. To avoid packet loss, when the occupancy of the buffer reaches a first threshold value, further transmission of a first-class type of data is precluded from the particular source of that data then being received, while transmission from other sources of that same first-class type of data is not precluded from these other data sources until first-class type of data from such other sources is also received. Further, data of a second-class type is not precluded from being transmitted as long as the amount of data stored in the buffer remains below a second threshold, which is greater than the first threshold.

Abstract: Novel rate-based flow control methods operate in conjunction with a data communications network. Such networks include a plurality of interconnected nodes, wherein each node is adapted for connection to any of a plurality of sources. The sources send data to, and receive data from, the nodes. The path that data follows in traveling from a first source, through one or more nodes, to a second source, is referred to as a virtual circuit path. Each node includes a processor and an associated memory for storing a data queue of data received from sources. According to one embodiment, referred to as first-order rate-based flow control, a node allocates a data transfer rate to a source based upon the difference between the current queue length at that node and the queue threshold of that node multiplied by a gain.