Search

The interaction of intelligent agents implies the existence of an environment to support it. The usual representations of this environment are graphs with certain properties. Throughput is one of the most important characteristics of such graphs. A traditional metric, such as the usual shortest paths, forms the basis of the traditional throughput index. In this case, a metric is used to synthesize the distribution of multi-coloured flows in graphs more complex than trees. To achieve better results than when using ordinary shortest paths, one can use the Euclidian metric. Working with weighted graphs requires a generalization of the explicit form of the Moore-Penrose pseudo inversed incidence matrix. The validity of the generalization is confirmed by verification of the Penrose conditions. An example of using the Euclidian metric for the distribution of computer network flows is given. [ABSTRACT FROM AUTHOR]

Abstract The rapid growth of packet based Internet traffic and big data, associated with interconnected Data Centers (DC) and High Performance Computing (HPC) systems have imposed the need for ultrahigh link capacities and ultrahigh packet switching speeds, at network nodes. In order to overcome these ultrahigh demands, and particularly packet routing and forwarding, All Optical Label Swapping (AOLS) has been considered for many years as an established solution. This survey paper gives an updated and thorough investigation on AOLS technology and trends, based on a vast reference amount of research milestones throughout all this long time era. All types of labeling techniques are presented and compared, and their pros and cons are summarized all together. Moreover, important issues and directions for research are discussed, giving researchers guidelines and motivation for extended investigation. [ABSTRACT FROM AUTHOR]

In this paper, the problem of finite-time state estimation for delayed periodic neural networks over multiple-packet transmission is addressed. The components of measurement output are separately transmitted by multiple-packet transmission, and the randomly occurring packet dropouts of different channels are described by mutually independent Bernoulli processes. In order to improve the robustness of the estimator, a non-fragile estimator is designed. In addition, some sufficient criteria are given to ensure that the estimation error system is stochastically finite-time stable and stochastically finite-time bounded, and the gains of non-fragile estimator are then derived based on these results. Finally, simulation results are provided to illustrate the effectiveness of the proposed estimator design approach. [ABSTRACT FROM AUTHOR]

The paper presents a study of key aspects in the design of a flexible unified data plane capable of integrating both fronthaul and backhaul transport in future 5G systems. In this study, we first review candidate access and multiplexing technologies from the state of the art and assess their capability to support legacy and new fronthaul and backhaul traffic. We then propose a new design framework for the targeted flexible unified data plane, featuring a primary packet-switching path supported by an auxiliary circuit-switching for extreme low latency scenarios. This comprises a summary of the first results achieved in the 5G-Crosshaul EU project since its kick-off in July 2015. [ABSTRACT FROM AUTHOR]

Abstract: In many-core architectures different distributed applications are executed in parallel. The applications may need hard guarantees for communication with respect to latency and throughput to cope with their constraints. Networks on Chip (NoC) are the most promising approach to handle these requirements in architectures with a large number of cores. Dynamic reservation of communication resources in virtual channel NoCs is used to enable quality of service for concurrent communication. This paper presents a router design supporting best effort and connection-oriented guaranteed service communication. The communication resources are shared dynamically between the two communication schemes. The key contribution is a concept for virtual channel reservation supporting different bandwidth and latency guarantees for simultaneous guaranteed service communication flows. Different to state-of-the-art, the used scheduling approach allows to give hard guarantees regarding throughput and latency. The concept enables to adjust the bandwidth and latency requirements of connections at run-time to cope with dynamically changing application requirements. Due to its distributed reservation process and resource allocation it offers good scalability for many-core architectures. The implementation of a router and the required extension of a network interface to support the proposed concept are presented. The software perspective is discussed. An algorithm is presented that is used to establish guaranteed service connections according to the applications bandwidth requirements. Simulation results are compared to state-of-the-art arbitration schemes and show significant improvements of latency and throughput, e.g. for an MPEG4 application. Synthesis results expose the low area overhead and impact on energy consumption which makes the concepts highly attractive for QoS-constraint many-core architectures. [Copyright &y& Elsevier]

Abstract: The exponential increase in the data center network traffic has posed new challenges for achieving high throughput, low latency and energy consumption. To address these challenges, this paper presents a novel scheme that combines optical circuit and packet switching technologies together in a single optical cross-connect for data center networks. By utilizing fast tunable linecards and parallel array waveguide grating routers, the optical cross-connect can offer low latency, large scalability and high throughput in datacenter networks. A scheduling technique is designed to simultaneously accommodate circuit switching and packet switching in the optical cross-connect. The physical performance of this optical cross-connect in circuit and packet switching modes is investigated by experiments. In addition, the network performance of the optical cross-connect is evaluated through simulations under a mixed circuit/packet-switched traffic pattern. Results show that the network performance of the optical cross-connect does not degrade significantly with an increase in the number of racks, but it is affected by the circuit-switched traffic proportion. [Copyright &y& Elsevier]

Abstract: In application-layer distributed denial of service (DDoS) attacks, zombie machines attack the victim server through legitimate packets such that packets havelegitimate format and are sent through normal TCP connections. Consequently, neither intrusion detection systems (IDS) nor victim server can detects malicious packets. This paper proposes a novel scheme which is called ConnectionScore to resist against such DDoS attacks. During the attack time, anyconnection is scored based on history and statistical analysis which has been done during the normal condition. The bottleneck resources are retaken from those connections which take lower scores. Our analysis shows that connections established by the adversary give low scores. In fact, ConnectionScore technique can estimate legitimacy of connections with high probability.Toevaluate performanceofthe scheme,weperformexperimentson Emulabenvironmentusingreal traceroute data of ClarkNet WWW server. [Copyright &y& Elsevier]

Abstract: Due to the rapid development of network applications, today the Internet plays an important role in our everyday life. Users hope that the network is always speedy enough to help them access the Internet without any delay. But the real situation is far from the ideal case. In the future, network researchers will continuously improve the network speed, and try to develop networks that are robust, without any crashes or packet loss. In this paper, we propose an aggressive path switching scheme for SCTP. Before data transmission, the scheme selects the fastest path as the primary path to transmit packets. When the path fails or transmission quality is poor, this scheme evaluates alternate paths, and selects the one with the best quality as the new primary path to substitute for the original one. After that, packets are delivered through the new path. Several factors are considered in the evaluation, including bandwidth, encryption/decryption, size of the congestion window, retransmission policy, routing policy, etc. [Copyright &y& Elsevier]

Abstract: In the problem of buffer management with bounded delay, packets with weights and deadlines arrive at a network switch over time, and the goal is to send those packets on the outgoing link while maximizing the total weight of the packets that are sent before their deadlines. We present a study of randomized algorithms that are competitive against an adaptive adversary. Previous studies considered only the oblivious adversary model that does not capture dependency of network traffic on the packet scheduling algorithm. We give a new analysis of a previously known algorithm, which shows that it remains -competitive even against an adaptive adversary. We complement this with a 4/3 lower bound on the competitive ratio on 2-bounded instances, in which each packet has a lifespan of one or two steps. We also study more restricted 2-uniform instances, in which every packet has a lifespan of exactly two steps. For such instances we give a 1.2 lower bound on the competitive ratio of arbitrary algorithms and 4/3 lower bound on the competitive ratio of memoryless scale-invariant algorithms. Finally, we devise a 4/3-competitive memoryless scale-invariant algorithm for 2-bounded instances, matching two of these lower bounds. [Copyright &y& Elsevier]

Abstract: The burstiness of video traffic in future wired and wireless networks makes dynamic management of network resources more critical. This helps to meet stringent delay and loss requirements of video traffic and improves its Quality of Service (QoS). Since buffer management in queueing system plays an important role towards effective control of QoS for various types of applications, we have focused on its dynamic management. In this paper, we have proposed ADPBS scheme for priority queueing system. The performance of this scheme is analyzed with MPEG-4 encoded video sequence as input to the ADPBS queue. The simulation is carried out in MATLAB for various combinations of threshold control parameters, different traffic load and input traffic mix variations. The results of simulations indicate that dynamically controlled threshold in ADPBS contributes to significant reduction of packet loss of different priority classes as compared with static partial buffer sharing queue and first in first out queue based on threshold control parameters and the traffic type. [Copyright &y& Elsevier]

Abstract: This paper proposes a novel method to study the modelling problem of a networked control system. We first identify the minimum packet drop sequences for a given plant or controller using the dynamics of the plant or controller. Then we represent these minimum packet drop sequences as states of a Markov chain. The state transition of the Markov chain is triggered at each packet transmission. Finally, this new modelling technique is demonstrated using the most commonly employed PID controller. [Copyright &y& Elsevier]

Abstract: In active networks, the Execution Environment in an active node executes user codes to tailor the processing of packets to application needs. However, the existing implementation of a software-based active node has a dilemma of only using the user mode Execution Environment or, alternatively, only using the kernel mode Execution Environment because neither mode of the Execution Environments meets application needs. The dilemma stems from the choice between high overheads of a user mode Execution Environment and poor services of a kernel mode Execution Environment in executing user codes. In this paper, we propose the Dual-Mode Execution Environment to overcome this dilemma, i.e. arguing for the necessity of an Execution Environment that supports dual modes. Currently, we develop and make the Lifetime-Sensitive Quantity-based Policy the workload adjustment policy in the Dual-Mode Execution Environment. We implement the prototype in Windows 2000. We conduct experiments to compare the prototype with active nodes that uses either the user mode Execution Environment or the kernel mode Execution Environment. We prove that the prototype meets application needs and outperforms the compared active nodes. [Copyright &y& Elsevier]

Abstract: An all-optical differential group delay (DGD) monitor for packet-switched networks is proposed. The monitoring approach consists of an integrated active Mach–Zehnder interferometer acting as a logic XOR gate. According to the estimated DGD value, a latching switch is employed to route the input packets “on-the-fly”. The simulation results show a successful operation which has been confirmed with the experimental validation of the XOR-based monitoring subsystem. [Copyright &y& Elsevier]

Abstract: The stationary nature of nodes in a mesh network has shifted the main design goal of routing protocols from maintaining connectivity between source and destination nodes to finding high-throughput paths between them. Numerous link-quality-based routing metrics have been proposed for choosing high-throughput routing paths in recent years. In this paper, we study routing metrics for high-throughput tree or mesh construction in multicast protocols. We show that there is a fundamental difference between unicast and multicast routing in how data packets are transmitted at the link layer, and accordingly how the routing metrics for unicast routing should be adapted for high-throughput multicast routing. We propose a low-overhead adaptive online algorithm to incorporate link-quality metrics to a representative multicast routing protocol. We then study the performance improvement achieved by using different link-quality-based routing metrics via extensive simulation and experiments on a mesh-network testbed, using ODMRP as a representative multicast protocol. Our extensive simulation studies show that: (1) ODMRP equipped with any of the link-quality-based routing metrics can achieve higher throughput than the original ODMRP. In particular, under a tree topology, on average, ODMRP enhanced with link-quality routing metrics achieve up to 34% higher throughput than the original ODMRP under low multicast sending rate; (2) the improvement reduces to 21% under high multicast sending rate due to higher interference experienced by the data packets from the probe packets; (3) heavily penalizing lossy links is an effective way in the link-quality metric design to avoid low-throughput paths; and (4) the path redundancy from a mesh data dissemination topology in mesh-based multicast protocols provides another degree of robustness to link characteristics and reduces the additional throughput gain achieved by using link-quality-based routing metrics. Finally, our experiments on an eight-node testbed show that on average, ODMRP using SPP and PP achieves 14% and 17% higher throughput over ODMRP, respectively, validating the simulation results. [Copyright &y& Elsevier]

Abstract: We propose a novel 2×2 wavelength-convertible optical switch based on dual-pump fiber parametric devices: one is driven by linearly parallel pumps, and the other one by perpendicular pumps. Theoretical analysis is made on the polarization effects on the switching performance of the two devices. The result predicts that two incident signals which are positioned symmetrically with respect to one pump can be switched independently, with judicious combinations of the relative pump-signal polarization states. Simulations performed in OptiSystem show that the scheme can achieve crosstalk-free packet switching with acceptable extinction ratios for both signals. Besides, future applications of this novel scheme in high-speed switching nodes are discussed. [Copyright &y& Elsevier]

Abstract: This paper presents an analysis of the energy consumption in a number of optical switch fabric architectures for optical packet-switched applications and compares them to electronic switch fabrics. Optical packet switching does not appear to offer any substantial power consumption advantages over electronic packet switching. Therefore, there is no compelling case for optical packet switching. [Copyright &y& Elsevier]

Abstract: We describe the practical and fundamental limitations of the more prominent optical buffering approaches. The architectural implementation and needs of an optical packet switch are used as a foundation for the study. We also present initial results for a buffered, all-optical, 40 Gb/s packet switch. [Copyright &y& Elsevier]

Abstract: We consider the use of random linear network coding in lossy packet networks. In particular, we consider the following simple strategy: nodes store the packets that they receive and, whenever they have a transmission opportunity, they send out coded packets formed from random linear combinations of stored packets. In such a strategy, intermediate nodes perform additional coding yet do not decode nor wait for a block of packets before sending out coded packets. Moreover, all coding and decoding operations have polynomial complexity. We show that, provided packet headers can be used to carry an amount of side-information that grows arbitrarily large (but independently of payload size), random linear network coding achieves packet-level capacity for both single unicast and single multicast connections and for both wireline and wireless networks. This result holds as long as packets received on links arrive according to processes that have average rates. Thus packet losses on links may exhibit correlations in time or with losses on other links. In the special case of Poisson traffic with i.i.d. losses, we give error exponents that quantify the rate of decay of the probability of error with coding delay. Our analysis of random linear network coding shows not only that it achieves packet-level capacity, but also that the propagation of packets carrying “innovative” information follows the propagation of jobs through a queueing network, thus implying that fluid flow models yield good approximations. [Copyright &y& Elsevier]

In this work, we study the impact of the dynamic changing of the network link capacities on the stability properties of packet-switched networks. Especially, we consider the Adversarial, Quasi-Static Queuing Theory model, where each link capacity may take on only two possible (integer) values, namely 1 and under a-adversary. We obtain the following results: [•] Allowing such dynamic changes to the link capacities of a network with just ten nodes that uses the LIS (Longest-in-System) protocol for contention–resolution results in instability at rates and for large enough values of . [•] The combination of dynamically changing link capacities with compositions of contention–resolution protocols on network queues suffices for similar instability bounds: The composition of LIS with any of SIS (Shortest-in-System), NTS (Nearest-to-Source), and FTG (Furthest-to-Go) protocols is unstable at rates for large enough values of . [•] The instability bound of the network subgraphs that are forbidden for stability is affected by the dynamic changes to the link capacities: we present improved instability bounds for all the directed subgraphs that were known to be forbidden for stability on networks running a certain greedy protocol. [Copyright &y& Elsevier]

Abstract: We present an efficient routing approach for delivering packets in complex networks. On delivering a message from a node to a destination, a node forwards the message to a neighbor by estimating the waiting time along the shortest path from each of its neighbors to the destination. This projected waiting time is dynamical in nature and the path through which a message is delivered would be adapted to the distribution of messages in the network. Implementing the approach on scale-free networks, we show that the present approach performs better than the shortest-path approach and another approach that takes into account of the waiting time only at the neighboring nodes. Key features in numerical results are explained by a mean field theory. The approach has the merit that messages are distributed among the nodes according to the capabilities of the nodes in handling messages. [Copyright &y& Elsevier]

Abstract: In an open shortest path first (OSPF) based best effort network, when a packet experiences congestion, the routing subsystem cannot send it through an alternate path. Thus, it fails to provide desired quality of service (QoS) during congestion. In order to provide QoS we have reported three different load sensitive routing (LSR) protocols in [A. Sahoo, An OSPF based load-sensitive QoS routing algorithm using alternate paths, in: IEEE International Conference on Computer Communication Networks, October 2002; A. Tiwari, A. Sahoo, Providing QoS support in OSPF based best effort network, in: IEEE International Conference on Networks, November 2005; A. Tiwari, A. Sahoo, A local coefficient based load sensitive routing protocol for providing QoS, in: IEEE International Conference on Parallel and Distributed Systems, July 2006]. The LSR protocol forwards packets through alternate paths in case of congestion. The number of alternate paths at any node depends on the value of operating parameter or coefficient used for alternate path calculation. Though the basic protocol in these cases was the same, the methods of choosing operating parameter were different. We referred to these three methods as LSR [A. Sahoo, An OSPF based load-sensitive QoS routing algorithm using alternate paths, in: IEEE International Conference on Computer Communication Networks, October 2002], E-LSR [A. Tiwari, A. Sahoo, Providing QoS support in OSPF based best effort network, in: IEEE International Conference on Networks, November 2005] and L-LSR [A. Tiwari, A. Sahoo, A local coefficient based load sensitive routing protocol for providing QoS, in: IEEE International Conference on Parallel and Distributed Systems, July 2006] coefficient methods. In this paper, we present the LSR protocol along with the three coefficient calculation methods pointing out the reason for going from one method to the next. The main strength of our LSR protocol is that it provides loop free alternate paths in the event of congestion and can interwork with routers running vanilla OSPF protocol. We show through simulation that the LSR protocol based on any of the three different coefficient calculation methods performs much better than OSPF and that out of the three methods proposed by us, L-LSR performs the best. [Copyright &y& Elsevier]

Abstract: In this paper, we discuss different signaling techniques for optical burst-switched networks. We develop a generalized signaling framework for optical burst-switched networks, which provides guidelines about the performance of each signaling technique based on the different parameters in the framework. The two commonly used signaling techniques in optical burst switching are two-way based tell-and-wait (TAW) and one-way based just-enough-time (JET). TAW suffers from high end-to-end packet delay, while JET suffers from high packet loss. There is no signaling technique that offers flexibility in terms of both loss and delay. We propose a hybrid signaling technique called intermediate-node-initiated (INI) signaling for optical burst-switched networks. INI can provide different levels of loss and delay characteristics based on end-user application requirements. The granularity of INI ranges between the one-way based and the two-way based signaling techniques. In INI reservation of channels is initiated at an intermediate node, known as the initiating node, in both forward and backward directions at the same time. We show that by appropriately selecting the initiating node, we can simulate both TAW and JET using the INI signaling technique. Through simulations, we shown that INI performs better than TAW in terms of average end-to-end packet delay and better than JET in terms of burst loss probability. We extend the INI signaling technique to provide QoS differentiation in the OBS core, differentiated INI (DINI), by carefully choosing different initiation nodes depending on delay and loss requirements of end-user applications. Through extensive simulations, we show that the DINI technique outperforms the existing offset-based QoS technique. [Copyright &y& Elsevier]

Abstract: A strategy to implement adaptive routing in irregular networks is presented and analyzed in this work. A simple and widely applicable deadlock avoidance method, applied to a ring embedded in the network topology, constitutes the basis of this high-performance packet switching. This adaptive router improves the network capabilities by allocating more resources to the fastest and most used virtual network, thus narrowing the performance gap with regular topologies. A thorough simulation process, which obtains statistically reliable measurements of irregular network behavior, has been carried out to evaluate it and compare with other state-of-the-art techniques. In all the experiments, our router exhibited the best behavior in terms of maximum/sustained performance and sensitivity to the network topology. [Copyright &y& Elsevier]

Abstract: This paper discusses a new idea for improving the recovery of (n, k, m) convolutional-code-based packet-level FEC. We extend the coefficients in the generator matrix to the elements on GF(28). Each byte in the redundant packets is generated independently, assuming the bytes are the elements on GF(28). The postreconstruction receiving rate is analytically derived from the necessary conditions for recovery. Moreover, the ability to recover lost packets is estimated based on analysis, and we demonstrate that the extension of coefficients improves the number of recovered packets more than the conventional method where coefficients are 0 or 1. [Copyright &y& Elsevier]

Abstract: A novel packet bit error rate (BER) and loss measurement method and system is proposed. A proposed 40 Gbit/s packet BER and loss measurement system is expressed in detail. A 40 Gbit/s BER and loss measurement with various conditions is demonstrated experimentally. In real time, only the payload part of a packet and burst stream with fluctuated guard time is evaluated. The BER and packet loss of a randomly received packet sequence due to routing and buffering can be also evaluated by the measurement system. A 10 Gbit/s packet BER and loss measurement with optical label switching, buffering, and preamble-free optical packet 3R are demonstrated experimentally. [Copyright &y& Elsevier]

Abstract: This paper deals with optical packet switches with limited buffer capabilities, subject to asynchronous, variable-length packets and connection-oriented operation. The focus is put on buffer scheduling policies and queuing performance evaluation. In particular a combined use of the wavelength and time domain is exploited in order to obtain contention resolution algorithms that guarantee the sequence preservation of packets belonging to the same connection. Four simple algorithms for strict and loose packet sequence preservation are proposed. Their performance is studied and compared with previously proposed algorithms. Simulation results suggest that by accepting some additional processing effort it is possible to guarantee very low packet loss probabilities while avoiding the out-of-sequence delivery. [Copyright &y& Elsevier]

Abstract: We investigate an optimal network structure for packet flow on large-scale networks. For this aim, we introduce a cost function which represents efficiency of the packet flow. Our strategy for obtaining an optimal network is to reconnect links in the network so as to minimize the defined cost function. We apply this strategy to a packet communication network in which a packet routing is controlled by using neural networks. We found that the optimal network shows a scale-free property for large degree k when the buffer-size distribution has a power-law form and the probability with which a node is chosen as a destination of a packet is proportional to the buffer size of the node. [Copyright &y& Elsevier]

Abstract: We consider a problem motivated by the design of Asynchronous transfer mode (ATM) networks. Given a physical network and an all-to-all traffic, the problem consists in designing a virtual network with a given diameter, which can be embedded in the physical one with a minimum congestion (the congestion is the maximum load of a physical link). Here we solve the problem when the physical network is a ring. We give an almost optimal solution for diameter 2 and bounds for large diameters. [Copyright &y& Elsevier]

Abstract: The paper addresses the topic of long-haul optical networking for the provision of large-bandwidth IP services. A class of optical packet switching architectures is considered which adopts an arrayed wavelength grating device as packet router. The architecture performs slotted packet switching operations and fully exploits the wavelength routing capabilities by allowing multi-wavelength switching. Fiber delay lines are used to perform optical packet buffering, which accomplishes either input queueing or shared queueing. Here a thorough performance evaluation is carried out with different buffering configurations and the effect of various switch parameters on traffic performance is studied. [Copyright &y& Elsevier]

Abstract: We consider the problem faced by a server offering multiple services with adversarial service request sequences. The server may offer a single service at a time and suffers a fixed latency whenever it switches the type of offered service. This problem captures realistic features of traffic and packet routing on network components such as multiplexers. We state the problem as a packet routing problem on bounded size buffer networks and then examine the crucial issue of stability—under what conditions will the number of unserviced requests remain bounded as the system runs for an arbitrarily long period of time? We obtain a tight characterization in terms of a natural packet density criterion for star networks with bounded buffer size. [Copyright &y& Elsevier]

This paper proposes a new energy efficient algorithm to find and maintain routes in mobile ad hoc networks. The proposal borrows the notion of learning from a previous research on cognitive packet networks (CPN) to create a robust routing protocol. Our idea uses smart packets that exploit the use of unicasts and broadcasts to search for routes. Because unicasts impose lower overall overhead, their use is preferred. Smart packets learn how to make good unicast routing decisions by employing a combined goal function which considers both the energy stored in the nodes and path delay. The end result is a dynamic discovery of paths that offer an equilibrium between low-delay routes and an efficient use of network resources that extends the working lifetime of the network. [Copyright &y& Elsevier]

Routing of packets in networks requires that a path be selected either dynamically while the packets are being forwarded, or statically (in advance) as in source routing from a source node to a destination. Quality of service (QoS) driven routing has been proposed using a protocol called the “Cognitive Packet Network” (CPN) which dynamically selects paths through a store and forward packet network so as to provide best effort QoS to route peer-to-peer connections. CPN operates very much as an adhoc protocol within a wired setting, and uses smart packets to select routes based on QoS requirements. We extend the path discovery process in CPN to include a genetic algorithm which can help discover new paths that may not have been discovered by smart packets. We describe how possible routes can “evolve” from prior knowledge, and then be selected based on “fitness” with respect to QoS. We detail the design of the algorithm and of its implementation, and report on resulting QoS measurements. [Copyright &y& Elsevier]

The telecommunications industry is going through a technological revolution, involving a transition from multiple voice and data networks to integrated service networks using packet switching technologies. The paper describes a new framework (the IPCP framework) for capacity planning and costing in an IP network environment. Capacity planning is carried out in four stages, the first of which is based on the concept of effective bandwidth, with the other three addressing the needs of different classes of traffic (Real time, interactive data and streaming, and delay-tolerant services). The framework enables network operators to reduce costs by optimising their capacity requirements and, with the aid of the IP costing module, to determine the costs of the various services that use integrated IP networks, each of which may have a different set of service quality requirements. Illustrative results show that capacity requirements and costs per Mbit vary significantly by service type, a finding with far-reaching implications for business planning and pricing. The approach has been extended to support the design of the new pricing models that will be required in an IP environment and to provide a basis for decisions on traffic management and product portfolio optimisation. The paper also describes the policy implications of the migration to multi-service, packet-based networks, and emphasises the need for regulators, as well as operators, to gain an understanding of the new economics of service provision. [ABSTRACT FROM AUTHOR]

Proposes an efficient routing algorithm and a new model for evaluating the average packet delay in high-speed computer networks. Need to take into account the level of congestion over each link; Selection of the best possible routes for each source/destination pair; Derivation of the model from the characteristics of high-speed links.

Abstract: Packet contention is a major issue in optical packet switching network and it is not a trivial task to resolve due to lack of optical RAM technology. In order to resolve contention optical buffering approach is used using fiber delay lines (FDLs). Yet there is a heavy packet loss rate due to unavailability of output port and free FDLs. This paper proposes a hybrid buffering architecture using feed-forward and feedback shared FLDs to resolve packet contention resolution of an optical packet switch. Feed-forward FDLs are used as primary buffer and feedback FDLs are implemented as supplementary buffer. Simulation result shows that proposed hybrid buffering switch achieves packet loss rate between 10−1 and 10−2 at heavy traffic load (ρ =0.9) for a 32×32 switch using different FDL length. [Copyright &y& Elsevier]