Search

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: Recently, the need of the high speed packet switch is increased. The basic 2DRR scheduling algorithm provides high throughput, fair access and simple working on a packet switch. However, few input and output node could not be permissioned in some timeslots. It occurs decreasing throughput and some transmission delay. This paper proposes a new packet switch scheduling algorithm. The proposed scheduling algorithm provides higher throughput and low delay. The effectiveness of the proposed algorithm is shown through simulation studies. [Copyright &y& Elsevier]

Abstract: We proposed and investigated superimposing intensity-modulated labels onto high-speed carrier-suppressed return-to-zero frequency shift keying-modulated payloads in optical label-switching packet networks. The transmission performances of 2.5Gb/s ASK label on 40Gb/s CSRZFSK payload is studied for the first time. [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: In the Optical Burst Switching (OBS) Network, the burst assembly technique is one of the challenging issues in the implementation of the system. It has the influence on the burst characteristic, which gives an impact on the network performance. Burst assembly is the process of assembling incoming data from the higher layer into bursts at the ingress edge node of the OBS network. The burst assembly mechanism must then place these packets into bursts based on some assembly policy. In this paper, the OBS system performance has been observed in simulated 12-node network based on Just-Enough-Time (JET) reservation protocol with various burst assembly techniques under the standard drop policy (DP) and the segmentation policy for contention resolution. The simulation results show that the performance of the proposed Adaptive-Threshold with Fixed Maximum Time Limitation (ATH-FMTL) burst assembly scheme is better than conventional burst assembly schemes in terms of loss probability and average assembly delay. Also, the proposed scheme avoids a sudden increase in the burst size and makes the burst sent out smoother as compared to conventional schemes. [Copyright &y& Elsevier]

Abstract: This paper proposes a novel Network-on-Chip architecture that not only enhances network transmission performance while maintaining a feasible implementation cost, but also provides a power-efficient solution for interconnection network scenarios. Diagonally-linked mesh NoC that uses wormhole packet switching technique implements a high-performance NoC platform to meet both cost and power consumption requirements. The proposed architecture uses an adaptive quasi-minimal routing algorithm so that it can improve average latency and saturation traffic load owing to its flexibility and adaptiveness. Based on these features, a congestion-aware routing algorithm is proposed to balance traffic load so as to alleviate congestion caused by high throughput network activities. Simulation results show that saturation load is improved dramatically for various traffic patterns. Implementation results also show that employing diagonal links is a more area-efficient method for improving network performance than using large buffers. It is shown that congestion-aware router requires negligible cost overhead but provides better throughput. Finally, simulation results also reveal that power consumption in the proposed architecture outperforms traditional mesh networks. [Copyright &y& Elsevier]

Abstract: TCP performance over bufferless Optical Burst Switched (OBS) networks could be significantly degraded due to the misinterpretation of network congestion status (referred to as false congestion detection). It has been reported that burst retransmission in the OBS domain can improve the TCP throughput by hiding burst loss events from the upper TCP layer, which can effectively reduce the congestion window fluctuation at the expense of introducing additional delay. However, the additional delay may cause performance degradation for delay-based TCP implementations that are sensitive to packet round trip time in estimating the network congestion status. In this paper, a novel implementation of TCP Vegas that adopts a threshold-based mechanism is proposed for identifying the network congestion status in OBS networks. Analytical models are developed to evaluate the throughput of conventional TCP Vegas and threshold-based Vegas over OBS networks with burst retransmission. Simulation is conducted to validate the analytical model and to compare threshold-based Vegas with a number of legacy TCP implementations, such as TCP Sack and TCP Reno. The analytical model can be used to obtain a proper threshold value that results in an optimal steady state TCP throughput. [Copyright &y& Elsevier]

Abstract: In this paper, we investigate the low coverage problem of efficient broadcast protocols in wireless ad hoc networks with realistic physical layer models. To minimize energy consumption, efficient protocols aim to select small set of forward nodes and minimum transmission radii. In ideal physical layer model, nodes within forward nodes’ transmission ranges can definitely receive packets; therefore energy efficient protocols can guarantee full coverage for broadcasting. However, in networks with a realistic physical layer, nodes can only receive packets with probability. We present an analytical model to show that the transmission radii used for nodes can be used to establish a tradeoff between minimizing energy consumption and ensuring network coverage. We then propose a mechanism called redundant radius, which involves using two transmission radii, to form a buffer zone that guarantees the availability of logical links in the physical network, one for broadcast tree calculation and the other for actual data transmission. With this mechanism, we extend well-known centralized protocols, BIP and DBIP, and corresponding localized protocols, LBIP and LDBIP. The effectiveness of the proposed scheme in improving network coverage is validated analytically and by simulation. [Copyright &y& Elsevier]

Abstract: We propose a new design of the secure packet switching device using the nonlinear behaviors of soliton in a micro ring resonator, where the nonlinear penalty of light traveling in the device becomes beneficial. The chaotic signals are generated by a Kerr effects nonlinear type of the input soliton pulse in a micro ring resonator, where the control input power can be used to specify the output filtering signals. Some device parameters are chosen and simulated using the proposed model. The potential of using such a device for communication security is performed and discussed. For instance, the packet switching of the chaotic encoding data increases from the chaotic signal encoding of 100bits−1. Results obtained have shown the potential of using such a proposed device for the tunable bandpass and band-stop filters, in which packet switching data can be performed and secured. [Copyright &y& Elsevier]

Abstract: We propose a new design of secured packet switching generated by using nonlinear behaviors of light in a micro ring resonator. The use of chaotic signals generated by the micro ring resonator to form the filtering and packet switching characteristics is described, where the high-capacity and security switching using such form is presented. The key advantage is that the high capacity of communication data can be secured in the transmission link, where the nonlinear penalty of light traveling in the device is beneficial. For instance, the required information can be transmitted and retrieved by using the proposed packet switching scheme. In principle, the chaotic signals are generated by a Kerr effects nonlinear type of light in a micro ring resonator, where the control input power can be specified by the required output filtering signals. The ring radii used range between 10 and 20μm, κ=0.0225, α=0.5dB and n 2=2.2×10−15 m2/W. Simulation results obtained have been described based on the practical device parameters. Three forms of the applications have been simulated, the potential of using for the tunable band pass and band stop filters, in which high-capacity packet switching data can be performed, and the fs switching time is plausible. [Copyright &y& Elsevier]

Abstract: Active queue management (AQM) is a key congestion control scheme for reducing packet loss and improving network utilization in TCP/IP networks. This paper proposes a proportional–integral-derivative (PID) controller as an active queue manager for Internet routers. Due to the limitations of packet-dropping probability and the effects of propagation delays in TCP networks, the TCP AQM network was modeled as a time-delayed system with a saturated input. An improved genetic algorithm is employed to derive optimal or near optimal PID controller gains such that a performance index of integrated-absolute error (IAE) is minimized, and thereby a stable queue length, low packet loss, and high link utilization for TCP networks are guaranteed. The performance of the proposed control scheme is evaluated in various network scenarios via a series of numerical simulations. [Copyright &y& Elsevier]

Abstract: This paper presents the architecture of a Wavelength Division Multiplexing (WDM) optical packet network, called WONDER, that was designed and prototyped in the PhotonLab at Politecnico di Torino, Italy. The design and implementation of the WONDER network aim to assess the effectiveness of optical technologies with respect to electronic ones, trying to identify an optimal mix of the two technologies. The architecture shows interesting resilience properties that enable the design of fast fault-recovery schemes. In this paper, we present the physical topology and node structure of the prototype, and discuss the implementation and performance of a fault-recovery algorithm. [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: In this paper, we propose the optical multicast-capable packet switch network based upon OC-label switching, which can enhance scalability in the number of multicast members because this approach can combine the wavelength with the optical code as the labels. The optical implementation features two key components. Firstly, a multiport encoder and a decoder are newly introduced, which allows one to generate and process the optical-code labels simultaneously, thus ensuring a good scalability. Secondly, an optical multicast-capable matrix switch which is composed of 1×2 TO-SWs enables the dynamical updating of the multicast forwarding table. Finally, this multicast-capable optical packet switched network is experimentally demonstrated. [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: 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: We evaluate the performance of a novel technique to equalize power variation between optical bursts using feed-forward control of semiconductor optical amplifier gain. The technique enables large dynamic range power equalization of incoming optical bursts with up to 10dB power difference. Moreover, the technique can remove SOA-induced waveform distortion. We achieve more than 4dB sensitivity improvement with equalized burst power. [Copyright &y& Elsevier]

Abstract: In this paper, we demonstrate mitigation of pattern-induced degradation in an optical crosspoint switch (OXS) matrix by utilizing differential phase shift keying (DPSK) modulation format. We experimentally demonstrate 4×4 unicast optical packet switching and dynamic reconfiguration for 4-channel, 200GHz spacing of RZ-DPSK payloads. Reconfigurable time as fast as 2ns is achieved owing to the optimized control circuit and device fabrication. The power and wavelength dependence are obtained for the RZ-DPSK payload. We also investigate the cascadability of the OXS based on re-circulating loops. Due to the great suppression of the pattern effect in OXS, DPSK has shown dramatical improvement of switching properties compared to conventional ON–OFF keying (OOK) signal. The DPSK payload can outperform OOK for 3.2dB after 9 hops optical switching. [Copyright &y& Elsevier]

Abstract: Optical switching technology can be categorized into optical circuit switching (OCS), optical packet switching (OPS) and optical burst switching (OBS). OCS is suitable for large amounts of data transmission; however, the channel utilization is inefficient when the traffic flows are intermittent. OPS can be easily adapted to any higher layer and is suitable for bursty traffic, but it requires a highly complex technology and optical buffer. The new switching paradigm, OBS, can provide higher bandwidth utilization and meanwhile avoid the complexity in OPS technology. In this paper, we investigate how the quality of service (QoS) can be guaranteed and reliable transmission can be supported in the OBS-based Internet backbone. We propose the adjustable-time-counter-based (ATCB) burst assembly and the non-real time packet retransmission mechanisms and apply them in the ingress router of the OBS Internet backbone to guarantee the quality of real time applications and lossless requirement of non-real time services. Moreover, traffic shaped is performed for real time packets in the egress router so that the real time property is preserved with a low jitter. Simulation results show that the burst blocking probability using the ATCB burst assembly is improved, compared with the time-counter-based (TCB) and burst-length-threshold-based (BLTB) mechanisms. The delay, loss and jitter of real time service conform to the QoS requirement. Meanwhile, the delay of non-real time service also falls in the acceptable range. [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: In this work, we propose and evaluate mechanisms for the multiplexing and the integrated delivery of various traffic types such as video, data and voice, over a wireless cellular high-speed packet switched network. Two different scenarios are examined where the video traffic results from videoconference sessions and high-quality media playback, respectively. In both cases we focus on the uplink channel and we thoroughly investigate, by using actual MPEG-4 video streams, the system''s performance under a variety of possible loads. Our goal is to achieve high-aggregate channel throughput while preserving the quality of service requirements of each traffic type. [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: 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]

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]