Abstract: Providing different levels of quality of service for different data flows being transported over a data link requires a very fast way to classify individual packets. Providing meaningful classification generally requires classifying data packets in several dimensions. A classification method represents a rule base as a hierarchy of linked tables and sequentially matches each parameter value in a packet signature against tables in the hierarchy. The method supports longest prefix matching and avoids time consuming backtracking by adding rules to the rule base.

Abstract: A multiplex system for multiplexing packets into ATM cells to be transmitted, which can implement effective use of channels corresponding to irregular traffic qualities in services with various types of quality conditions in an actual environment. In response to a connection establishment request (S402), current required bandwidths B1, . . . , Bm are changed to B′1, . . . , B′m by adding the new connection, which causes bandwidths X1, . . . , Xm which are assigned to the channels to be changed. When the desired bandwidth including the requested connection is less than an available bandwidth of the corresponding channel, an assigned bandwidth change processing (S406) is activated to assign new bandwidths in accordance with desired bandwidths. The bandwidth assignment change is carried out by changing ratios of extraction rates of packets from the buffers in the multiplex system.

Abstract: In an asynchronous transfer mode (ATM) network, ATM cells received are classified to the queues appropriate to the service classes required by the ATM cells. The status registers manage the controlled delay of the ATM cells for the service classes and the queue length of the ATM cells which queue up in the queues. On the basis of the controlled delay and the queue length, the scheduler adaptively determines a weight, on the basis of which the ATM cells queuing up in the queues are to be forwarded to thereby effectively control the delay of ATM cells to be forwarded.

Abstract: A data transmission system is described between a central location, connected to a data cell transmission network, for example, an ATM (Asynchronous Transfer Mode) network and a peripheral user-network termination unit, connected to the central location by means of a plurality of digital transmission lines. A lower data transmission rate may be transmitted over each of the digital transmission lines than the data transmission rate of the transmission network, whereby an inverse multiplexing device is provided in each of the central location and in the peripheral user-network termination unit. The inverse multiplexing device in the peripheral user-network termination unit may be assembled from a first and, optionally, one or several further multiplexing modules, whereby each multiplexing module is connected to one of the digital transmission lines. At least one unit is provided for the control and synchronization of partial data cell streams.

Abstract: A hardware-based policy engine that employs a policy cache to process packets of network traffic. The policy engine includes a stream classifier that associates each packet with at least one action processor based on data in the packet, and the action processor further acts on the packets based on the association determined by the stream classifier.

Abstract: The present invention, generally speaking, uses input buffering and output control to provide a high-speed, high-performance digital traffic switch. This approach solves all of the problems noted above with respect to the prior art (input buffering/input control, output buffering/output control). Dropped discrete information units (cells) are dropped at the input port, and so will not be transmitted across the switch fabric. This reduces the traffic load on the switch fabric during congested periods, and makes the switch fabric easier to design and expand. Input buffering/output control allows for the use of smaller buffers than output buffered/output control architectures for the same level of “discrete information unit (cell) drop” performance, and scales well to larger systems. Input buffering/output control provides all the information necessary to the output (data flow) controller necessary to implement very precise control algorithms.

Abstract: Methods for allocating bandwidth among MCR and best effort connections include listing MCR connections in an MCR service list and best efforts connection in a best efforts (BE) service list. Assigning an MCR value to each MCR connection and setting a Cell Count Register (CCR) with it. During a service interval, dequeueing each MCR connection queue in round robin fashion according to the MCR service list and decrementing the associated CCR. If the CCR reaches zero before the end of the service interval and there are still cells in the queue, the connection is moved from the MCR service list to the BE service list for the remainder of the service interval. If the CCR reaches zero before the end of the service interval and/or there are no cells remaining in the queue, the connection is removed from the MCR service list.

Abstract: A method for establishing a multimedia connection with quality of service (QoS) using an ATM backbone for ISDN network or IP network calls. QoS makes IP over ATM useful for video and audio conferencing by ensuring a minimum packet error rate at acceptable bit transmission rates. The invention will utilize the H.323 annex C protocol to transmit IP gateway transmissions through an ATM backbone network. This invention enables H.320 endpoints having a connection to an ATM network to send QoS communications to other endpoints. When call setup is initiated between two endpoints, an ISDN (or IP) call is sent to a gateway. The gateway will utilize a network gatekeeper to route the call to the addressed endpoint's corresponding gateway. When a route is established, the call will be converted to an H.323 annex C protocol transmission and sent through the ATM backbone to the destination gateway.

Abstract: A method of minimizing throughput delay in constant-bit-rate services carried over packet-based networks subject to variable delays, comprises, in one embodiment, the steps of receiving incoming packets in a buffer, reading out bits from the buffer at a clock frequency fi, continually monitoring the buffer fill level Li, determining the maximum fill level Lmaxj over a plurality of successive samples, determining the minimum fill level Lmink over a plurality of successive samples, adjusting the clock frequency fi to cause the maximum fill level Lmaxj to tend toward a target value TargetLmax, and adaptively changing said target value TargetLmax so that the minimum fill level Lmink tends toward a predetermined set-point. The rate of change of the target value TargetLmax is significantly slower than the rate of adjustment of clock frequency. The invention can be applied to other types of clock recovery.

Abstract: A method for mapping and multiplexing of constant bit rate (CBR) signals into optical transport network (OTN) frames is provided. The method, in addition, enables the transportation of data from a plurality of SONET/SDH clients through a single OTN frame. The preferred method thereby enables efficient adoption of SONET/SDH legacy equipment by OTN networks.

Abstract: Providing different levels of quality of service for different data flows being transported over a data link requires a very fast way to classify individual packets. Providing meaningful classification generally requires classifying data packets in several dimensions. A classification method processes multiple parameter values for a packet in parallel to obtain answer sets indicating which rules are matched by each parameter value. Answer indexes identify logical blocks in each answer set which contain TRUE values. The method performs an AND operation on the answer indexes to identify those blocks in the answer sets which could contain bits corresponding to matched rules. An AND operation is performed on the identified blocks to identify the particular rule matched by the packet. The classification method allows extremely fast wire speed packet classification.

Abstract: Arbitration for a switch fabric (e.g., an input-buffered switch fabric) is performed. The switch fabric has a set of ports. Each port from the set of ports is associated with its own set of links. The set of ports includes a first port and a second port. A link is selected from the set of links associated with the first port based on a weight value associated with each remaining link associated with a candidate packet and being from the set of links associated with the first port. A first penalty for a weight vector entity associated with the first port is determined by based on a weight value associated with each link from a first subset of links from the set of links for the first port. Each link from the first subset of links is not associated with a candidate packet.

Abstract: A Digital Subscriber Line (xDSL) is used to connect Customer Premises Equipment (CPE) to a telecommunications network. The Customer Premises Equipment generates both Constant Bit-Rate (CBR) and Variable Bit-Rate (VBR) Packets. Each Frame of Packets from the Customer Premises Equipment is used to transmit up to a limited amount of CBR data, and VBR data is used, if available, to fill up the Frame. The limit on the amount of CBR data can be dynamically adjusted according to the need of the CPE. Similarly, and importantly, a limit on CBR data to the CPE can be adjusted dynamicaly according to the need for transmission of CBR data to the CPE. Advantageously, a guaranteed rate of transmission of CBR data can be maintained, even in the face of a flood of VBR traffic. Advantageously, this arrangement improves the quality of service on CBR traffic, such as Voice, and subject to the limit imposed by CBR traffic, allows a maximum amount of VBR traffic to be transmitted.

Abstract: A device for routing message cells transferred by asynchronous transfer mode, provided with a counter to maintain the declared message cell rate for a block within an overall available message cell rate. In order to maintain a predetermined granularity for all division ratios the counter clock follows the message cell cycle during fractional overflow.

Abstract: An ATM-based delay adaptive scheduling apparatus adaptive according to a traffic type and method thereof. A scheduling portion categorizes an input cell according to the traffic type, and generates service information of the cell suitably for the traffic type of the cells. A controlling portion determines a priority of cell service provision based on the service information, and an outputting portion reads a corresponding cell from the storing portion according to the service providing priority determined by the controlling portion, and outputs the read cell to an ATM switch. By generating the service information of each cell in the form of a tag, and by determining a priority of service provision according to the generated service information, an adequate QoS is guaranteed for each traffic type under a multi-traffic environment, and an efficient use of bandwidth provided in a current network is achieved by using the characteristics of each traffic type.

Abstract: A virtual storage adapter provides networked data storage to a data processing device for delivering consumer entertainment services using virtual devices accessed over a high-speed quality-of-service-enabled communications network. A data storage device emulation unit emulates the functionality of a data storage device (e.g., a DVD or a CD) and a network interface comprising an IP Small Computer System Interface (“iSCSI”) compatible interface connects the data storage device emulation unit to an iSCSI storage gateway. The virtual storage adapter provides video on demand (“VoD”) services using a video on demand server comprising a video on demand portal for selection and an administration unit for billing. Personal video recorder services are also provided, including data expiration, capacity on demand, consolidated recording and community recording features.

Abstract: A method for adjusting an ATM switch local service policy based on a non-ATM protocol service parameter, the method including the steps of inspecting the payload of an ATM PDU received at a switch along at least one VCC to identify a non-ATM PDU protocol identifier included in the payload, inspecting the payload to identify a non-ATM PDU service identifier associated with the non-ATM PDU protocol identifier, and selectively adjusting a local service policy attribute within the switch for the at least one VCC based on the non-ATM PDU service identifier in accordance with an adjustment value previously associated with the non-ATM PDU protocol identifier and the non-ATM PDU service identifier.

Abstract: A method and apparatus are provided for scheduling unicast and multicast data in an input-queued network device. According to one aspect of the present invention, a combined schedule is created by pipelined staging of multicast and unicast scheduling. Multicast cells are scheduled for transmission among multiple interfaces of a crossbar by performing a multicast cell scheduling cycle for multiple classes of service that are supported by the network device. Then, unicast cells are scheduled for transmission among the interfaces at a lower priority than the previously scheduled multicast cells by performing a unicast cell scheduling cycle for the multiple classes of service using only those interfaces that remain unmatched after completion of the multicast cell scheduling cycle.

Abstract: The method shares available bandwidth on a common link in a communication network among a plurality of data flows which are transmitted via the common link. The method is used by a processor and includes sharing reserved bandwidth included in the available bandwidth among the plurality of data flows, and sharing unreserved bandwidth among the plurality of data flows according to a respective unreserved data packet share which is associated to each one of the plurality of data flows. The unreserved bandwidth is included in the available bandwidth in excess of the reserved bandwidth. The sharing of the unreserved bandwidth includes associating to one of the plurality of data flows a respective adaptable administrative weight and determining the respective unreserved data packet share which is associated to the one data flow as a function of its respective adaptable administrative weight.

Abstract: A system and method for scheduling the transmission of ATM cells is provided which includes two discrete processors. One processor examines the virtual channels and their traffic parameters, and calculates the times at which cells should be transmitted from each channel. The second processor manages multiple ATM network ports, performs low-level cell handling and the majority of cell switching, and transmits cells when instructed by the first.

Abstract: A method and system for dynamically adjusting the total bandwidth that an asynchronous transfer mode (ATM) switching system can make available to Available Bit Rate (ABR) virtual circuits comprise the steps of by determining a set of weighted “cutoffs” for the ABR virtual circuits, respectively, determining a first total expected rate (Exp_Rate) for recently active virtual circuits that are bottlenecked elsewhere based on the weighted cutoffs, setting a second total expected rate for active virtual circuits that are bottlenecked elsewhere to the first total expected rate, determining a total bandwidth available in the switching system for active virtual circuits that are bottlenecked in the switching system based on the first total expected rate, and setting to zero the first total expected rate.

Abstract: Methods and devices useful in high-speed scalable switching systems include a memoryless switch fabric, per virtual channel queuing, digital phase aligners, randomized and complement connection modes, a mid-point negative acknowledge and output negative acknowledge scheme among other elements. A particular implementation of a routing table and switch element is described in part to illustrate the various techniques and devices of the invention.

Abstract: A congestion avoidance scheme for ABR services in an ATM satellite system is described. The scheme relies on the broadcast nature of a satellite system to control the rates at which user terminals can send their requests for capacity. The scheme is integrated with the uplink scheduler mechanisms and therefore it is capable of achieving high bandwidth efficiency. It also achieves fairness in satellite resource utilization, while guaranteeing low cell loss ratio with rather modest buffer size.

Abstract: A method and system for forwarding data-packets in a data-over-cable system, is provided. The data-packets received by the head-end of the data-over-cable system are sorted according to the Quality-of-Service identifiers assigned to the destination for the respective data-packets. The sorted data-packets are forwarded subsequently in accordance with the Quality-of-Service settings corresponding to their respective Quality-of-Service identifiers. Data-packets that cannot be transmitted in accordance with their respective Quality-of-Service identifiers are cached for transmission at a later time point.

Abstract: A non-geostationary satellite network incorporates a plurality of satellite nodes and ground stations in communication with the nodes. Routing and control are established from a virtual model of the network. Within the virtual model, a capacity of space segment band width for different traffic QoS classes can be determined. The relationship between the virtual model and the real network is used to transfer the capacity determination to the real network.

Abstract: The present invention intends to realize highly reliable communications between a frame relay network and an ATM network by corresponding service classes decided in both networks to each other. In order to achieve the above object, the frame relay data communication apparatus of the present invention used to allow communications between the frame relay network and the ATM network is provided with a frame receiver unit for receiving frame data from the frame relay network; a cell assembly unit for assembling received frame data into ATM cells and transmitting assembled cells to the ATM network; and a controller for controlling both frame receiver unit and cell assembly unit so as to extract priority order information from received frame data and receive priority order information of data used in ATM networks from an ATM network and decide a service class of the received data to assemble the received frame data into cells according to the decided service class.

Abstract: The method for servicing queues holding messages, such as ATM data packets, for subsequent processing or transmission to a resource such as a communications link having a finite processing capability comprises the steps of servicing each queue by forwarding the messages thereof to the resource at time intervals corresponding to a guaranteed service rate of the queue, provided the queue is non-empty; and, during time intervals when none of the queues have messages being forwarded to the resource in conformance with the above step, servicing the queues in accordance with a proportion of a remaining or idle resource bandwidth allocated to each queue.

Abstract: Congestion is controlled in an internetwork having at least two segments coupled by a router where at least one connection between communication devices passes through the router. Each connection is assumed to use a window-based flow control protocol between its source and destination. On receiving an acknowledgment from a connection in the router, where the acknowledgment contains a window size set by the destination, the router adaptively determines a second window size for the connection based on the router's average buffer occupancy and its instantaneous buffer occupancy. If the window size in the acknowledgment exceeds this second window size, the window size in the acknowledgment is overwritten to select the second window size. The router then forwards the acknowledgment to the source, thereby controlling the window size available to the source as a function of the congestion in the router.

Abstract: A system and a method are disclosed for supporting multiple application traffic types over connection oriented networks. Data is received from multiple applications, for example in the form of data units, and is associated with a traffic type. The traffic type associated with a data unit indicates whether the data unit is inelastic traffic or elastic traffic. Data associated with inelastic traffic is mapped to at least one connection of a first connection type which provides for some amount of committed bandwidth, and limits on delay variation. Data associated with elastic traffic is mapped to at least one connection of a second connection type, which does not provide any committed bandwidth. Connections of the second connection type may ensure that elastic traffic data units that are accepted for transfer by the underlying network are delivered without loss due to network congestion, for example, by use of a flow control technique.

Abstract: A Multi-Protocol Over ATM (MPOA) network being scalable so as to allow service providers to provide internetworking services to subscribers. The MPOA network is divided into virtual private networks to provide intranet and Internet services over an ATM backbone. The internetworking management system is able to assign differentiated classes of service to the virtual private networks. This permits a service provider to offer subscribers the options of different levels of service.

Abstract: Asynchronous Transfer Mode (ATM) data is transmitted in Available Bit Rate (ABR) service over a network path including a spacecraft. The spacecraft payload switches do not provide an indication of congestion, so conventional ABR feedback control using Resource Management cells is ineffective. In one avatar of the invention, the Network Control Center coacting with the spacecraft produces signals representative of congestion in services other than ATM ABR service, and these congestion signals are coupled to the terrestrial source terminal, where return or back Resource Management cells are modified with data derived from the congestion signals, to close a feedback loop including the source of ATM ABR signals, the source terminal, and the spacecraft. The feedback loop tends to maintain excess bandwidth in use for ABR purposes, and tends to prevent congestion.

Abstract: The invention utilizes two-stage shaping and two-priority queuing thereby allowing both shaped and unshaped virtual circuits to be provisioned in a single virtual path. For each VP, a separate dynamic buffer is set up for each shaped VC and unshaped VC within the VP. The shaped cells stored in dynamic buffers are dequeued via VC scheduling (first stage shaper) to a high priority queue according to the shaped VC contracts, and the unshaped cells stored in dynamic buffers are dequeued in a round robin manner to a low priority queue. The outputs of both the high priority queue and the low priority queue are passed to a second stage shaper where cells from the high priority queue are scheduled according to the VP contract, and cells from the low priority queue are also scheduled according to the VP contract, but only when VP bandwidth is not being used by the high priority cells.

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.