Showing papers on "Fast packet switching published in 2005"

A protocol for packet network intercommunication

Abstract: A protocol that supports the sharing of resources that exist in different packet switching networks is presented. The protocol provides for variation in individual network packet sizes, transmission failures, sequencing, flow control, end-to-end error checking, and the creation and destruction of logical process-to-process connections. Some implementation issues are considered, and problems such as internetwork routing, accounting, and timeouts are exposed.

System and method for policing multiple data flows and multi-protocol data flows

Abstract: A system and method for policing one or more flows of a data stream of packets associated with differing transmission protocols. The current capacity level for each flow is determined, as is the packet protocol associated with each packet. A packet parameter in the packet that is indicative of the bandwidth consumption of the packet is identified. The packet parameter is converted to a predetermined format if the packet is not associated with a predetermined packet protocol. A common bandwidth capacity test is performed to determine whether the packet is conforming or non-conforming, and is a function of the packet parameter and the current bandwidth capacity level.

Packet combining in sensor networks

Abstract: This paper presents the Simple Packet Combining (SPaC) error-correction scheme for wireless sensor networks. Nodes buffer corrupt packets, and when two or more corrupt versions of a packet have been received, a packet combining procedure attempts to recover the original packet from the corrupt copies. Packet combining exploits the broadcast medium and spatial diversity of a multi-hop wireless network by using packets overheard at any node, in addition to the next-hop destination of the packet itself. Unlike point-to-point forward error correction (FEC), packet combining therefore helps multi-node interactions such as multi-hop routing or broadcasting as well as to hop-by-hop communication. Also, SPaC does not transmit redundant overhead on good links and does not require costly probes to estimate channel conditions.We have implemented SPaC as a link-layer extension on sensor nodes; it is transparent to upper layer protocols and has low memory and CPU footprints. We evaluate performance through a combination of analysis, trace-driven simulation, indoor and outdoor testbed micro-benchmarks, and deployment on a live network. The results show significant performance gains, even when accounting for the energy cost of CPU processing. We also present detailed bit-level link measurements and the design and evaluation of a new preamble detection scheme motivated by these measurements.

A fully implemented 12 /spl times/ 12 data vortex optical packet switching interconnection network

Abstract: A fully functional optical packet switching (OPS) interconnection network based on the data vortex architecture is presented. The photonic switching fabric uniquely capitalizes on the enormous bandwidth advantage of wavelength division multiplexing (WDM) wavelength parallelism while delivering minimal packet transit latency. Utilizing semiconductor optical amplifier (SOA)-based switching nodes and conventional fiber-optic technology, the 12-port system exhibits a capacity of nearly 1 Tb/s. Optical packets containing an eight-wavelength WDM payload with 10 Gb/s per wavelength are routed successfully to all 12 ports while maintaining a bit error rate (BER) of 10/sup -12/ or better. Median port-to-port latencies of 110 ns are achieved with a distributed deflection routing network that resolves packet contention on-the-fly without the use of optical buffers and maintains the entire payload path in the optical domain.

Method and apparatus for per-service fault protection and restoration in a packet network

Abstract: A method and apparatus are disclosed for per-service flow protection and restoration of data in one or more packet networks. The disclosed protection and restoration techniques allow traffic to be prioritized and protected from the aggregate level down to a micro-flow level. Thus, protection can be limited to those services that are fault sensitive. Protected data is duplicated over a primary path and one or more backup data paths. Following a link failure, protected data can be quickly and efficiently restored without significant service interruption. A received packet is classified (420) at each end point based on information in a header portion of the packet, using one or more rules that determine whether the received packet should be protected (430). At an ingress node (400), if the packet classification determines that the received packet should be protected, then the received packet is transmitted on at least two paths (440). At an egress node (500), if the packet classification determines that the received packet is protected, then multiple versions of the received packet are expected and only one version of the received packet is transmitted (550).

Packet Transmission Control Device and Packet Transmission Control Method

Abstract: The present invention relates to a packet transmission control device which controls transmission of packets to a plurality of mobile stations. A scheduling unit of the packet transmission control device according to the present invention is configured to schedule the packets to each of the plurality of mobile stations, based on an average transmission rate, a minimum guaranteed transmission rate, a scheduling frequency and capability information.

Wireless packet transfer apparatus and method

Abstract: An error correction encoding rate selection table is provided in an error correction processing unit of a packet transfer apparatus, and the table stores an error correction encoding rate preset to maintain a desired QoS in correspondence with a protocol type and an application type. When a transmission packet is transferred to a wireless transmission path, an encoding control unit judges the protocol type and application type of a transmission packet from a header of the transmission packet, in accordance with a judgement result and the error correction encoding rate selection table, an error correction encoding rate is selected, and the transmission packet is subjected to error correction encoding and transferred.

Internal load balancing in a data switch using distributed network process

Abstract: A data communications switch for dynamically distributing packet processing operations between an ingress and egress processor for load balancing is disclosed. The invention in the preferred embodiment features a switching device including a plurality of switching modules, each of the switching modules including a packet classifier for identifying one or more packet processing operations to be applied to an ingress packet and a controller adapted to allocate each of the identified one or more packet processing operations between a first set of packet processing operations and a second set of packet processing operations, execute the first set of packet processing operations at the ingress processor at which the packet was received, and transmit instructions to the egress processor to execute the second set of packet processing operations. The egress processor then executes the second set of packet processing operations, after which the packet may be transmitted toward its destination node.

Packet aware scheduler in wireless communication systems

Abstract: Apparatuses and methodologies are described that facilitate packet aware scheduling are provided. In some embodiments, if all of the information of a packet cannot be scheduled in a single transmission period, additional resources may be assigned to transmission of the contents of the packet based upon latency requirements and/or transmission constraints of the packet.

Method and apparatus for dynamically controlling traffic in wireless station

Abstract: A method and apparatus dynamically control data traffic, such as multimedia streams, needing a guaranteed Quality of Service (QoS) and normal data traffic, according to a variable communication environment. The method of dynamically controlling traffic in a wireless station includes reading header information of a packet received from an upper layer and determining a type of the packet, setting a priority according to the type of the packet, adjusting a size of a variable buffer by performing appropriate dynamic buffering according to the type of the packet, enqueuing the packet in a fixed buffer if the priority is high and enqueuing the packet in the variable buffer if the priority is low, and transmitting the packet enqueued in the fixed buffer to a destination station prior to the packet enqueued in the variable buffer.

Packet concatenation in wireless networks

Abstract: A wireless network includes a transmitting device and a plurality of receiving devices. The transmitting device is configured to receive a plurality of data packets, including a first data packet and a second data packet, prepare a preamble, prepare a signal field for each of the plurality of data packets, including a first signal field based on the first data packet and a second signal field based on the second data packet, and broadcast the preamble, the first signal field, the first data packet, the second signal field, and the second data packet as a concatenated packet.

Apparatus and method for two-stage packet classification using most specific filter matching and transport level sharing

Abstract: A method and apparatus for two-stage packet classification. In the first stage, which may be implemented in software, a packet is classified on the basis of the packet's network path and, perhaps, its protocol. In the second stage, which may be implemented in hardware, the packet is classified on the basis of one or more transport level fields of the packet. An apparatus of two-stage packet classification may include a processing system for first stage code execution, a classification circuit for performing the second stage of classification, and a memory to store a number of bins, each bin including one or more rules.

Packet generation systems and methods

Abstract: Disclosed herein are various embodiments of methods, systems, and apparatus for increasing packet generation in a digital communication system. In one exemplary method embodiment, multiple input signals are interpolated, shifted, and aggregated into a composite signal for transmission over a network.

Method and apparatus for managing packet data loss in a wireless network

Abstract: Various embodiments are described to address the need for more effective management of packet data loss in wireless communication systems. When a packet data destination (131) that is receiving a flow of packets for a packet data service instance indicates to the packet data source (141) of the flow that the flow should be suspended, it also indicates to the source how to process packets for the service instance while the flow transmission is suspended. For example, the packet data destination may indicate an event or condition that is triggering the flow suspension, the source can then begin buffering packets, discarding packets, starting timers, and/or taking other packet processing actions to manage packet data loss in view of the packet data destination's indication. Alternatively, the packet data destination may explicitly indicate the packet processing actions the source should take while the packet flow is suspended.

Data rate shifting methods and techniques

Abstract: A technique for determining when to change a data rate by determining the cause of packet loss. The technique distinguishes between collision mediated packet loss and poor signal mediated packet loss. Rate shifting to a lower rate is performed after determining poor signals are causing packet loss. After switching to a lower rate, the packet loss rate can be compared to the pre-switch packet loss rate. If the packet loss rate has not improved by shifting to a lower data rate, then the data rate can be shifted to a higher rate. The technique can use a combination of channel response, signal strength, packet loss rate and throughput to determine when to switch data rates. A communication unit can maintain separate histories for each unit it is communicating with and employ a different data rate for each unit.

Viable opto-electronic HPC interconnect fabrics

Abstract: We address the problem of how to exploit optics for ultrascale High Performance Computing interconnect fabrics. We show that for high port counts these fabrics require multistage topologies regardless of whether electronic or optical switch components are used. Also, per stage electronic buffers remain indispensable for maintaining throughput, lossless-ness and packet sequence. Although the notion of true all-optical packet switching is not yet viable, we show that appropriate use of optical switching technology offers power and scaling advantages that can be leveraged economically, and propose a hybrid opto-electronic HPC interconnect fabric architecture that combines the strength of electronics in processing and storing information with the strength of optics in switching and transporting high bandwidths. Using Semiconductor Optical Amplifier technology, we are building a prototype demonstrator switch that we believe solves all the technical challenges. Having reached this threshold now enables commercialization of this technology, which we are currently pursuing.

Packet scheduling in a wireless local area network

Abstract: A method for scheduling packets in a wireless local area network begins by mapping a packet to an access category (AC) based on a user priority of the packet (102). The packet is assigned to a traffic flow (TF) (104) in a station based on the AC of the packet. A packet from the TF is placed into a transmission queue (106) for the AC. A packet from the transmission queue is selected based on a quality of service-based contention resolution function (108), and the selected packet is transmitted (114).

Method for performing packet switched handover in a mobile communication system

Abstract: The invention relates to a method and system for performing packet switched handover in a mobile communication network. The system comprises a mobile node, a first and a second packet switching node. The method enables the parallel sending of logical link layer frames from the first and the second packet switching node. This is achieved so that the mobile node does not reject incoming frames received from two logical link layer entities having different states. The benefits of the invention are related to improved quality of service and the avoiding of gaps in received data during handover.

Access network device for managing queue corresponding to real time multimedia traffic characteristics and method thereof

Abstract: A queue management method of an access network device includes receiving a packet, determining feasibility of a packet transmission within a delivery deadline allowed from a destination if the received packet is for real-time transmission, storing the packet in the transmission queue and transmitting the packet in sequential order of the storage when the packet transmission within the delivery deadline is feasible, and dropping the packet instead of storing the packet in the transmission queue when the packet transmission is determined infeasible. Accordingly, resources required for the packet transmission are saved.

Fault detection device

Abstract: A fault detection device capable of detecting network faults by itself with high accuracy in multi-vendor environments, without the need to interoperate with an associated device according to an identical protocol. A monitoring control packet transmitter generates a fault monitoring control packet and transmits the generated packet to the associated device with which the fault detection device need not interoperate to detect faults according to the same protocol. A transmit packet counter keeps count of the transmitted fault monitoring control packet. A receive packet counter receives a control packet transmitted from the associated device, and keeps count of the received control packet. A fault detector monitors the count of transmitted packets and the count of received packets and, if at least one of the counts remains unchanged for a fixed period of time, judges that a fault has occurred and sends a fault notification to outside.

Congestion control network relay device and method

Abstract: A congestion control network relay device capable of preventing redundant retransmission of packets which are already delivered to a receiving-side device. When an acknowledgment packet is detected by an acknowledgment packet detector, a receive packet manager stores acknowledgment information in an acknowledgment information memory. If first and second data packets are retransmitted thereafter from a transmitting-side device and input to the congestion control network relay device, a packet reception determination unit judges, for example, that the first data packet has not yet been received by the receiving-side device while the second data packet has already been received by the receiving-side device. In this case, a packet transfer unit transfers the first data packet to the receiving-side device and discards the second data packet.

Scheduling method for wireless packet data channel

Abstract: A scheduler at a base station may schedule packet data traffic based on a ranking metric that varies directly with the mobile station's scheduling downlink transmission rate and a delay factor indicative of the staleness of the corresponding queued data. The ranking metric may advantageously vary in a direct non-linear fashion with the delay factor to allow for delay sensitive data, such as VoIP data, to be scheduled with increased urgency when quality of service is about to be compromised. The scheduler may attempt to pack a multi-user downlink physical layer packet by selecting a tentative rate and determining if an aggregate amount of data in the packet may be increased by transmitting the packet at a lower rate. If so, additional queued data is added to the packet and the transmission rate for the packet is lowered. Such an approach allows for greater link efficiency to be achieved.

An optical packet switch based on WDM technologies

Abstract: Dense wavelength-division multiplexing (DWDM) technology offers tremendous transmission capacity in optical fiber communications. However, switching and routing capacity lags behind the transmission capacity, since most of today's packet switches and routers are implemented using slower electronic components. Optical packet switches are one of the potential candidates to improve switching capacity to be comparable with optical transmission capacity. In this paper, we present an optically transparent asynchronous transfer mode (OPATM) switch that consists of a photonic front-end processor and a WDM switching fabric. A WDM loop memory is deployed as a multiported shared memory in the switching fabric. The photonic front-end processor performs the cell delineation, VPI/VCI overwriting, and cell synchronization functions in the optical domain under the control of electronic signals. The WDM switching fabric stores and forwards cells from each input port to one or more specific output ports determined by the electronic route controller. We have demonstrated with experiments the functions and capabilities of the front-end processor and the switching fabric at the header-processing rate of 2.5 Gb/s. Other than ATM, the switching architecture can be easily modified to apply to other types of fixed-length payload formats with different bit rates. Using this kind of photonic switch to route information, an optical network has the advantages of bit rate, wavelength, and signal-format transparencies. Within the transparency distance, the network is capable of handling a widely heterogeneous mix of traffic, including even analog signals.

Method and apparatus for using multiple modulation schemes for a single packet

Abstract: Techniques for using multiple modulation schemes for a single packet are described. Each data packet is processed and transmitted in up to T blocks, where T > 1. Multiple modulation schemes are used for the T blocks to achieve good performance. A transmitter encodes a data packet to generate code bits. The transmitter then forms a block of code bits with the code bits generated for the packet, determines the modulation scheme to use for the block (e.g., based on a mode/rate selected for the packet), maps the code bits for the block based on the modulation scheme to obtain data symbols, and processes and transmits the block of data symbols to a receiver. The transmitter generates and transmits another block in similar manner until the data packet is decoded correctly or all T blocks have been transmitted. The receiver performs the complementary processing to receive and decode the packet.

Packet processing using encapsulation and decapsulation chains

Abstract: A method for processing packets in a router includes specifying operations on packets as chains of processing elements. Each chain is uniquely associated with one interface/protocol pair, and each processing element performs at least one function on a packet. An incoming packet is received, and processed, first by a demultiplexor element which determines the protocol of the next higher level used by the packet. Then, the packet is processed by the elements of a decapsulation chain associated with the interface on which the packet was received, and by the elements of an encapsulation chain associated with the interface on which the packet is to be transmitted. The demultiplexor element or operation passes the packet on to a decapsulation chain associated with the protocol and with the incoming interface, depending on protocol information contained in the incoming packet. Decapsulation and encapsulation chains can be built dynamically, by inserting new and removing old elements as necessary as new protocols are developed and new features added. A chain walker walks through the chains, passing the processed packet to each element in a chain, until either the end of the chain is reached and processing is complete, or until the packet is dropped because no function can process it, or because a packet is processed by an outside process or by hardware, which may optionally stop the chain walk. A chain walk may be temporarily halted, or may be terminated. If temporarily halted, the chain walk can be resumed at any element in the chain, depending on the packet's requirements. A chain walk can also begin at any element in a chain.

Interrupting transmission of low priority ethernet packets

Abstract: A method according to one embodiment may include transmitting a first segment of a first packet. The first packet may have a first priority and be compliant with an Ethernet communication protocol. The method may further include interrupting transmitting of the first packet upon notice of a second packet for transmission. The second packet may have a second priority higher than the first priority, and the second packet may also be compliant with the Ethernet communication protocol. The method may further include transmitting an entirety of the second packet, and transmitting a second segment of the first packet after transmission of the entirety of the second packet. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Support of Micro-Mobility in MPLS-Based Wireless Access Networks

Abstract: In this paper, we propose an architecture for the MPLS (Multi-Protocol Label Switching)-based micro-mobility management including label switched path setup, packet forwarding, handoff processing, and paging. In order to prevent packet loss during handoff, we propose two packet recovery mechanisms, namely: buffer time-based packet recovery and medium access control (MAC) layer assisted packet recovery schemes. Simulation results show that the MAC layer assisted packet recuvery scheme has a better performance than buffer time-based scheme. Our proposed scheme provides a higher throughput when compared with other IP micro-mobility protocols including Cellular IP, HAWAII, and Hierarchical Mobile IP.

Multiplex scheme conversion apparatus

Abstract: A multiplex scheme conversion apparatus (103) includes (i) a packet loss judgment unit 202 that judges the packet loss of a TS packet, performs error processing in the case where a packet loss is detected, and outputs the payload data on which error processing has already been performed and (ii) a Box making unit 206 that makes 'moov' including error information and 'mdat' based on inputted AU data and the display time in a PES header

Advanced switching lost packet and event detection and handling

Abstract: Embodiments of the invention may provide a method to send a packet from an endpoint in an advanced switching fabric and starting a timer to run until receiving a response packet or receiving an event packet notifying of a device failure, save a copy of the sent packet, detect if the timer has expired, retransmit the packet after the timer has expired and resetting the timer; and run a faulty device detection algorithm if the packet has been retransmitted a predetermined number of times. Furthermore, some embodiments may provide an apparatus with a retransmit buffer, and an endpoint that can send a packet and save a copy of the packet in the retransmit buffer, detect if a timer expired and retransmit the packet after the timer has expired and no packet was received in response to the transmitted packet, and run a faulty device detection algorithm.

Packet generating method, video decoding method, media multiplexer, media demultiplexer, multimedia communication system and bit stream converter

Abstract: A moving image coded string is mapped with a set of information areas as one packet, and each packet is added with an error code and control information in a multiplexing part so that it is decided at the receiving side, from the result of error detection by decoding the error detection code, whether an error has occurred in each information area of the packet.