Showing papers on "Circuit switching published in 2002"

Analysis of a dynamically wavelength-routed optical burst switched network architecture

Abstract: The concept of optical burst switching (OBS) aims to allow access to optical bandwidth in dense wavelength division multiplexed (DWDM) networks at fractions of the optical line rate to improve bandwidth utilization efficiency. This paper studies an alternative network architecture combining OBS with dynamic wavelength allocation under fast circuit switching to provide a scalable optical architecture with a guaranteed QoS in the presence of dynamic and bursty traffic loads. In the proposed architecture, all processing and buffering are concentrated at the network edge and bursts are routed over an optical transport core using dynamic wavelength assignment. It is assumed that there are no buffers or wavelength conversion in core nodes and that fast tuneable laser sources are used in the edge routers. This eliminates the forwarding bottleneck of electronic routers in DWDM networks for terabit-per-second throughput and guarantees forwarding with predefined delay at the edge and latency due only to propagation time in the core. The edge burst aggregation mechanisms are evaluated for a range of traffic statistics to identify their impact on the allowable burst lengths, required buffer size and achievable edge delays. Bandwidth utilization and wavelength reuse are introduced as new parameters characterizing the network performance in the case of dynamic wavelength allocation. Based on an analytical model, upper bounds for these parameters are derived to quantify the advantages of wavelength channel reuse, including the influence of the signaling round-trip time required for lightpath reservation. The results allow to quantify the operational gain achievable with fast wavelength switching compared to quasistatic wavelength-routed optical networks and can be applied to the design of future optical network architectures.

Packet switching network, packet switching equipment, and network management equipment

Abstract: This invention provides a network management equipment and a packet switching equipment which eliminate a connection setup delay time, reduce a delay and a delay variation involved in data transfer, and effectively perform connectionless data flow processing in a large data network. The network is divided into a connection-oriented core network and a plurality of connectionless access networks connected to the core network where a plurality of connections (called permanent virtual route (PVR)) are set up among a plurality of edge nodes. The network management equipment selects one route from a plurality of PVRs for connectionless data flow received from one of the access networks and transfers data along the PVR.

Optical packet switching in core networks: between vision and reality

Abstract: The research on optical packet switching (OPS) has witnessed considerable progress in the 1990s. We examine the future potential of OPS in the core network by discussing this switching approach and the current status of a number of its enabling technologies. Many of these technologies are still in the stage of research and experimentation. We see that optical packet switching may be deployed in the long-term future subject to satisfaction of three main conditions/developments. First, additional technological developments have to take place to overcome remaining implementation challenges while making OPS cost-effective to deploy. Second, a rational migration scenario of the network toward gradual deployment of packet-based optical switching approaches should exist. Finally, carriers have to become more interested in packet-based optical switching solutions.

Passive network monitoring system

Abstract: A network monitoring system (10). The system comprises a database (32) and at least one monitoring circuit (36) coupled to a network (20). Network traffic flows along the network in a form of packets. The at least one monitoring circuit is programmed to perform the steps of receiving a packet communicated along the network and determining whether data in the packet satisfies a rule set. Further, the at least one monitoring circuit is responsive to determining that data in the packet satisfies a rule set by copying information relating to the packet to be stored into the database. The system also comprises circuitry for querying the information communicated by the at least one monitoring circuit to the database to identify an irregularity in the network traffic.

Method of providing packet voice call service in wireless communication network and network architecture therefor

Abstract: There is provided a method of providing a voice call service and an additional service to a circuit network terminal via a packet-based network, and a network architecture therefor. In the network architecture, a RAN provides a call service to the circuit network terminal, a mediation gateway makes the circuit network terminal recognized as a packet network terminal in the packet-based network by performing IP registration for the circuit network terminal. An access gateway provides predetermined traffic interfacing upon request from the mediation gateway and transmits voice traffic from the circuit network terminal to a terminal of a called party via the packet-based network.

Network routing apparatus for enhanced efficiency and monitoring capability

Abstract: According to an embodiment of the invention, a network device such as a router or switch provides efficient data packet handling capability. The network device includes one or more input ports for receiving data packets to be routed, as well as one or more output ports for transmitting data packets. The network device includes an integrated port controller integrated circuit for routing packets. The integrated circuit includes an interface circuit, a received packets circuit, a buffer manager circuit for receiving data packets from the received packets circuit and transmitting data packets in one or more buffers and reading data packets from the one or more buffers. The integrated circuit also includes a rate shaper counter for storing credit for a traffic class, so that the integrated circuit can support input and/or output rate shaping. The integrated circuit may be associated with an IRAM, a CAM, a parameter memory configured to hold routing and/or switching parameters, which may be implemented as a PRAM, and an aging RAM, which stores aging information. The aging information may be used by a CPU coupled to the integrated circuit via a system interface circuit to remove entries from the CAM and/or the PRAM when an age count exceeds an age limit threshold for the entries.

Virtual broadband communication through bundling of a group of circuit switching and packet switching channels

Abstract: A method of transmitting data across a telecommunication network, includes: partitioning a data stream (107) into a plurality of sub-streams (107(1)-107(n)); transmitting each sub-stream across an associated circuit switching channel (120) in one communication session; and reconstructing the plurality of sub-streams into a single data stream. An apparatus (100) for transmitting data from a source to a destination, includes: a channel bundler and de-bundler (105) capable to partition a data stream (107) into a plurality of sub-streams (107(1)-107(n)), the data stream transmitted from the source, the channel bundler and de-bundler (105) capable to reconstruct the sub-streams into a single data stream for transmission to the destination; and a plurality of circuit switching channels communicatively coupled to the channel bundler and de-bundler and capable to transmit an assigned sub-stream.

Circuit-switched and packet-switched communications

Abstract: A communication system comprising: a network having a first network access point and a second network access point and being capable of carrying data between the first network access point and the second access point by means of for example a packet-switched bearer and a circuit-switched bearer; and a first terminal capable of connection to the first network access point and a second terminal capable of connection to the second network access point, each terminal being capable of simultaneously supporting a packet-switched connection and a circuit-switched conn∩ction with the other terminal via the network as a single logical communication arrangement.

Call establishment method

Abstract: Summary The invention concerns the method of establishing a communication connection between a calling subscriber terminal and a called subscriber terminal connected to a circuit switched communication network, a terminal for a communication network and a server for the provisioning of services to calling subscriber terminals of a circuit switched communication network. A calling subscriber enters a request to access a called subscriber terminal. The subscriber terminal transfers an identification of the called subscriber to a mediation function element. The mediation function element transmits said identification of the called subscriber to an address translation server. The address translation server transmits a circuit switched network address of a terminal of the called subscriber to the mediation function element. The mediation function element initiates a call establishment by passing said address to a call handling function of the circuit switched communication network.

Hybrid hierarchical optical networks

Abstract: Hybrid hierarchical optical cross-connects enhance the performance/cost ratio of optical networks by providing transparent (optical) switching of sets of wavelengths (wavebands) in addition to opaque (electrical) switching of individual wavelengths. As network bandwidth gets cheaper, and the performance bottleneck moves to switching nodes, these systems provide an attractive scalable solution for next-generation optical networks. We describe key technological components (including flexible nonuniform wavebands) of hybrid hierarchical optical cross-connects and discuss their performance/cost implications.

Parallel routing algorithms in Benes-Clos networks

Abstract: A new parallel algorithm for route assignments in Benes-Clos (1962, 1953) networks is studied. Most known sequential route assignment algorithms, such as the looping algorithm, are designed for circuit switching systems where the switching configuration can be rearranged at relatively low speed. In packet switching systems, switch fabrics must be able to provide internally conflict-free paths simultaneously, and accommodate packets requesting connections in real time as they arrive at the inputs. In this paper, we develop a parallel routing algorithm for Benes networks by solving a set of Boolean equations which are derived from the connection requests and the symmetric structure of the networks. Our approach can handle partial permutations easily. The time complexity of our algorithm is O(log/sup 2/ N), where N is the network size. We also extend the algorithm and show that it can be applied to the Clos networks if the number of central modules is M=2/sup m/, where m is a positive integer. The time complexity is O(log N/spl times/log M) in this case.

Improving load balancing mechanisms in wireless packet networks

Abstract: This paper provides a comparative performance evaluation of various load balancing schemes in cellular packet networks. With respect to circuit switched networks, wireless packet technology adds the further issue of quality of service of accepted connections. In fact, with packet technology, transmission error performance does not uniquely depend on the perceived channel quality, but it can be improved by adopting a scheduling mechanism enforcing fast retransmission of corrupted packets. The result is that throughput can be traded off with QoS experienced by an admitted flow. This paper proposes new packet-level load balancing mechanisms. In addition to the number of calls admitted in a cell, our schemes use supplementary packet level information, expressed in terms of effective resource consumption of each individual call when retransmission mechanisms are employed. Simulation results prove the superiority of our proposed schemes with respect to traditional load balancing schemes.

Telecommunication system with packet-switched-multimedia-session-to-circuit-switched-call transferral

Abstract: Telecommunication systems with packet-switched multimedia terminals and nodes for packet-switched multimedia sessions and with servers for exchanging multimedia signaling information for the packet-switched multimedia sessions and with terminating units are provided with gateways for in response to transferral messages originating from the packet-switched multimedia terminals and arriving at the servers transferring packet-switched multimedia sessions between packet-switched multimedia terminals and nodes to circuit-switched calls between gateways and circuit-switched terminals via switches, to continue possibly interrupted sessions via replacing calls. The servers send invitation messages to gateways, which send setup messages to switches for setting up circuit-switched calls via partly alternative communication paths. The servers send information messages to terminating units for bringing the terminating units from session level to call level. Preferably, a packet-switched multimedia terminal and a circuit-switched terminal are one and the same terminal.

Method and system for interfacing a legacy circuit-switched network with a packet-switched network

Abstract: An interface engine that is communicatively connected to a packet-switched network and to a legacy circuit-switched network uses a call processing protocol, such as the session initiation protocol (SIP), for packet-switched network communications and uses a legacy signaling protocol, such as IS-41, for legacy circuit-switched communications. In response to a registration request initiated by a subscriber device on the packet-switched network, the interface engine obtains a service profile for the subscriber from a call processing system, such as a home location register (HLR), of the legacy circuit-switched network. Service parameters derived from the service profile and stored in a service database may be used to apply services on the packet-switched network for the subscriber device.

Enhanced call delivery system for interoperability between circuit switched and packet switched networks

Abstract: The invention expedites the delivery of a call originating in a circuit-switched network to a mobile terminal camped on a packet-switched network. Information representing the location of the mobile terminal in the packet-switched network is provided to the circuit switched network. A call setup with the mobile terminal is initiated with reference to the previously received location information, frequently more expeditiously and using less resources. Location-based services are also provided by the circuit-switched network with access to such mobile terminal location information.

Internet security device and method

Abstract: A device described herein may include an input port operable to receive data packets; a switching board operable to classify the data packets, determine whether the data packets should be accepted by the device, and determine whether received data packets are first data packets in a session; a management board operable to receive the data packets from the switching board that were determined by the switching board to be the first data packets in a session; and one or more processing boards operable to receive data packets from the switching board that were determined by the switching board to not be the first data packets in a session and to process the received data packets.

Packet transfer apparatus having network address translation circuit which enables high-speed address translation during packet reception processing

Abstract: In a packet transfer apparatus for transferring packets between first and second networks, a translated network address is assigned to a first node in the first network and having a first private network address when the first packet from the first node is transferred to a second node in the second network, and said translated network address is stored in an address management circuit associated with said first and second network addresses. Thereafter, address translation for realizing an NAT function is performed on subsequent packets transferred between the first and second nodes, by a dedicated hardware circuit and reference to the address management circuit, while performing processing for receiving the packets.

The performance of circuit switching in the internet

Abstract: Recently there has been renewed interest in circuit switching because of the ease of building very high capacity optical circuit switches. This poster studies the performance, as seen by the end user, of an Internet that uses circuit switching instead of, or in addition to, packet switching. TCP represents over 90% of current Internet traffic, which makes our usage of the network very connection oriented. Therefore, the key performance metric for the end user is the completion time for each connection, which we refer to as response time.On the face of it, simply considering circuit switching as an alternative would seem a pointless exercise; the Internet is packet switched, and was deliberately built that way to enable the efficiencies afforded by statistical multiplexing, and thus it should provide a response time that is faster than that of circuit switching. However, link utilization is low, and falling, particularly at the core of the Internet, which means that statistical multiplexing is less important than it once was.In this poster, we explore the performance of a network where a new circuit is created for each application flow, with particular emphasis on the response time experienced by users. We use simple M/G/1 and M/G/N queues to model application flows in both packet switched and circuit switched networks, as well as ns-2 simulations to validate the results. We conclude that because of high-bandwidth long-lived flows, it does not make sense to use circuit switching in shared access or local area networks. At the same time, our results suggest that in the core of the network, where access links limit the maximum flow rate, and where high capacity is needed most, there is little or no difference in performance between circuit switching and packet switching. Given that circuit switches can be built to have higher capacity than packet switches, this suggests that a circuit switched core warrants further investigation.There are other performance metrics that are also very important when deciding whether circuit switching is a good technology for the Internet, such as scalability, simplicity, cost, reliability and availability, Quality of Service (QoS), or traffic engineering. We have used such criteria in other studies, but they will not be discussed in the poster with great detail given the space constraints. The end result is that we greatly benefit from the use of circuit switching in the backbone of the Internet.Our current use of the network is very connection oriented, and, thus, it fits well with a network core that is circuit switched, while the edges use packet switching. We may just use a gateway that maps packet switched flows (e.g. TCP connections) to circuits. This gateway creates and destroys circuits as flows come and go. Then the deployment of circuit switching in the core does not require any change in existing end hosts and routers, which will continue to use IP the same way as today, as the gateways will hide the existence of circuits in the core. With this network architecture, circuit switched clouds can be inserted gradually, without requiring a flag day in the Internet.

Wide area multi-service communications network based on dynamic channel switching

Abstract: A networking approach is disclosed that combines the advantages of circuit switching and packet switching in an integrated communications network. With this approach, control signals are separated from the data and transmitted separately in a common control channel. Control and signaling operation can be viewed as a logical extension of generalized multi-protocol label switching (GMPLS). A variable number of data channels are dynamically assigned to each connection through the network. Channels are quickly switched in to accommodate the data flow through a connection and switched out when they are no longer needed. With this dynamic channel switching approach, a continuous data stream is not altered as it transverses the network and data channels are efficiently utilized even if the data source is bursty. The proposed approach is compatible with legacy networks and can provide a mechanism for convergence of circuit switching and packet switching. Most of the benefit of the proposed approach can be achieved with modifying only network and server equipment, but not necessarily client equipment, to support dynamic channel switching.

System having two or more packet interfaces, a switch, and a shared packet DMA circuit

Abstract: An apparatus includes a first interface circuit, a second interface circuit, a memory controller for configured to interface to a memory, and a packet DMA circuit. The first interface circuit is configured to couple to a first interface for receiving and transmitting packet data. Similarly, the second interface circuit is configured to couple to a second interface for receiving and transmitting packet data. The packet DMA circuit is coupled to receive a first packet from the first interface circuit and a second packet from the second interface circuit. The packet DMA circuit is configured to transmit the first packet and the second packet in write commands to the memory controller to be written to the memory. In some embodiments, a switch is coupled to the first interface circuit, the second interface circuit, and the packet DMA circuit.

Gemini: an optical interconnection network for parallel processing

Abstract: The Gemini interconnect is a dual technology (optical and electrical) interconnection network designed for use in tightly-coupled multicomputer systems. It consists of a circuit-switched optical data path in parallel with a packet-switched electrical control/data path. The optical path is used for transmission of long data messages and the electrical path is used for switch control and transmission of short data messages. The paper describes the architecture of the interconnection network and related communications protocols. Fairness issues associated with network operation are addressed and a discrete-event simulation model of the entire system is described. Network performance characteristics derived from the simulation model are presented. The results show significant performance benefits when using virtual output queuing and quantify the tradeoffs between throughput and fairness in the system.

Integrated communications system

Abstract: An Advanced Packet Based Integrated Communications System has the ability to provide commercial customers with converged services including local and long distance voice, data communications and videoconferencing and which also provides a platform to deliver value added services such as managed services, hosting, storage, messaging, and E-Business content (1024). The integrated communications system comprises an integrated packet-based network infrastructure operable to provide networked converged communications, an information management platform operable to support handling of orders, initiating services provisioning. Maintaining service quality, billing (1011), and administration and an activation engi ne operable to provide end-to-end services provisioning (1016). The integrated packet-based network infrastructure replaces a traditional circuit switched network.

TCP switching: exposing circuits to IP

Abstract: A simple technique could eliminate choke points on the the Internet. TCP switching, which integrates circuit switching benefits in the packet-switched Internet, demonstrates the possibilities. The research presented focuses on how the existing IP infrastructure can incorporate fast, simple (and perhaps optical) circuit switches. Several approaches to this already exist, but we propose a technique called transmission control protocol (TCP) switching in which each application flow (usually an individual TCP connection) triggers its own end-to-end circuit creation across a circuit-switched core. Based on IP switching, TCP switching incorporates modified circuit switches that use existing IP routing protocols to establish circuits. Routing occurs hop by hop, and circuit maintenance uses soft state, that is, it is removed through an inactivity time-out.

Mobile communication system and transmission mode switching method used therefor as well as recording medium having program of the same method recorded therein

Abstract: To provide a mobile communication system capable of easily performing selection of an optimal transmission mode. Upon receiving a receiving error notice from a mobile station, a transmission mode switching selecting portion of a base station forwards an instruction to switch a transmission mode to a mode slower than a current transmission mode to a modulation/coding portion. After receiving the receiving error notice, if the receiving error notice is not continuously received for a predetermined number of blocks Ns, the transmission mode switching selecting portion forwards an instruction to switch a transmission mode to a mode faster than the current transmission mode to the modulation/coding portion. The modulation/coding portion switches the modulation/coding code to any one of a QPSK modulation/coding circuit, a 16QAM modulation/coding circuit and a 64QAM modulation/coding circuit in response to the switching instruction and performs modulation/coding in the circuit switched to.

Network routing system for enhanced efficiency and monitoring capability

Abstract: According to an embodiment of the invention, a network device such as a router or switch provides efficient data packet handling capability. The network device includes one or more input ports for receiving data packets to be routed, as well as one or more output ports for transmitting data packets. The network device includes an integrated port controller integrated circuit for routing packets. The integrated circuit includes an interface circuit, a received packets circuit, a buffer manager circuit for receiving data packets from the received packets circuit and transmitting data packets in one or more buffers and reading data packets from the one or more buffers. The integrated circuit also includes a rate shaper counter for storing credit for a traffic class, so that the integrated circuit can support input and/or output rate shaping. The integrated circuit may be associated with an IRAM, a CAM, a parameter memory configured to hold routing and/or switching parameters, which may be implemented as a PRAM, and an aging RAM, which stores aging information. The aging information may be used by a CPU coupled to the integrated circuit via a system interface circuit to remove entries from the CAM and/or the PRAM when an age count exceeds an age limit threshold for the entries.

Packet network providing fast distribution of node related information and a method therefor

Abstract: A reliable packet network is constructed with nodes and links where the nodes use a method for fast distribution of link state information. This permits a rapid update of the routing information at all nodes in case of a link failure, minimizing the number of lost packets.

An algorithm for loopless deflection in photonic packet-switched networks

Abstract: We present a label-based approach for implementing deflection in a photonic packet network, and we introduce an algorithm for determining deflection options in a manner which eliminates looping. A general analytical model is developed to evaluate packet loss probabilities in networks with deflection. The analysis may be applied to a wide class of deflection schemes and may be applied to networks with any arbitrary topology. The analysis is verified through simulation.

Systems including packet interfaces, switches, and packet DMA circuits for splitting and merging packet streams

Abstract: An integrated circuit includes receive circuits for receiving packets, transmit circuits for transmitting packets, a packet DMA circuit for communicating packets to and from a memory controller, and a switch for selectively coupling the receive circuits to transmit circuits. The integrated circuit may flexibly merge and split the packet streams to provide for various packet processing/packet routing functions to be applied to different packets within the packet streams. An apparatus may include two or more of the integrated circuits, which may communicate packets between respective receive and transmit circuits.

Evaluation of open-loop sequence control schemes for multi-path switches

Abstract: Modern packet switches and routers are commonly designed using a multi-path architecture, in which the capacities of multiple switch cores are aggregated in order to build a higher capacity system. The local parallelism within such systems has been found to be the biggest contributing factor to packet re-ordering within the network. This motivates the employment of localized sequence control mechanisms that maintain the ordering of packets, belonging to the same flow, which are forwarded through different paths of the switch. The protocol chosen for this purpose has to maintain a low overhead and exhibit a favorable behavior under arbitrary dispatch patterns and differential delays. We analyze the performance of the sequence controller of a generic multi-path switch, and establish a sufficient condition which guarantees the stability of the system. Furthermore, we compare the behavior of three practical open-loop sequence control schemes using packet-level simulations. The results presented can be used as a reference to choose an appropriate protocol under the assumed traffic conditions.