2,281 research outputs found

    A Survey of Green Networking Research

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    Reduction of unnecessary energy consumption is becoming a major concern in wired networking, because of the potential economical benefits and of its expected environmental impact. These issues, usually referred to as "green networking", relate to embedding energy-awareness in the design, in the devices and in the protocols of networks. In this work, we first formulate a more precise definition of the "green" attribute. We furthermore identify a few paradigms that are the key enablers of energy-aware networking research. We then overview the current state of the art and provide a taxonomy of the relevant work, with a special focus on wired networking. At a high level, we identify four branches of green networking research that stem from different observations on the root causes of energy waste, namely (i) Adaptive Link Rate, (ii) Interface proxying, (iii) Energy-aware infrastructures and (iv) Energy-aware applications. In this work, we do not only explore specific proposals pertaining to each of the above branches, but also offer a perspective for research.Comment: Index Terms: Green Networking; Wired Networks; Adaptive Link Rate; Interface Proxying; Energy-aware Infrastructures; Energy-aware Applications. 18 pages, 6 figures, 2 table

    An improvement over TCP Vegas to enhance its performance in optical burst switching networks

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    This is a post-peer-review, pre-copyedit version of an article published in Optical review. The final authenticated version is available online at: http://dx.doi.org/10.1007/s10043-021-00652-w.The demand for high bandwidth on the Internet is growing drastically, and one of the solutions for tackling this problem is using optical networks. Burst switching is one of the techniques that can be used in optical networks to handle high traffic. Aside from the many advantages that this technique has, it suffers from a big flaw called burst contention. Optical burst switching (OBS) is a switching technique without any buffering system. As a result, when two bursts are trying to reserve one resource, one of them drops. This drawback can have a significant impact on the performance of some protocols like TCP because they have not been designed to perform in a network without any queuing system and cannot distinguish a drop is because of the congestion or contention. In this paper, a new algorithm called AVGR (Average of RTTs) is proposed based on some mathematical equations to prevent the degradation of TCP. It tries to calculate averages for some RTTs in three different periods. Then base on the obtained results, the congestion control mechanism will be modified. The primary goal of the algorithm is to determine the current status of the network and make proper decisions based on it.This work has been funded by the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya (2017 SGR 376) and the Spanish Government under Project PID2019-106808RA-I00 AEI/FEDER UE.Peer ReviewedPostprint (author's final draft

    A simulation-based study of TCP performance over an Optical Burst Switched backbone with 802.11 access

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    13th Open European Summer School and IFIP TC6.6 Workshop, EUNICE 2007, Enschede, The Netherlands, July 18-20, 2007. ProceedingsThe combined effect of optical and wireless subnetworks in an hypothetical future scenario where core networks have evolved to the still prototype Optical Burst Switching (OBS) technology is an open research issue. This paper studies this hybrid scenario, in the particular case of 802.11 access, by reviewing the key aspects of OBS and 802.11 with an impact on the performance of TCP, and makes a simulation-based assessment of the relative influence of both technologies over the effective end-to-end behaviour of TCP.This work has been partly supported by the EU under the IST e-Photon/One+ project (FP6-IST-027497) and by the Spanish CAPITAL project (TEC2004-05622-C04-03).Publicad

    Performance issues in optical burst/packet switching

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    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-01524-3_8This chapter summarises the activities on optical packet switching (OPS) and optical burst switching (OBS) carried out by the COST 291 partners in the last 4 years. It consists of an introduction, five sections with contributions on five different specific topics, and a final section dedicated to the conclusions. Each section contains an introductive state-of-the-art description of the specific topic and at least one contribution on that topic. The conclusions give some points on the current situation of the OPS/OBS paradigms

    A Survey of Quality of Service Differentiation Mechanisms for Optical Burst Switching Networks

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    Cataloged from PDF version of article.This paper presents an overview of Quality of Service (QoS) differentiation mechanisms proposed for Optical Burst Switching (OBS) networks. OBS has been proposed to couple the benefits of both circuit and packet switching for the ‘‘on demand’’ use of capacity in the future optical Internet. In such a case, QoS support imposes some important challenges before this technology is deployed. This paper takes a broader view on QoS, including QoS differentiation not only at the burst but also at the transport levels for OBS networks. A classification of existing QoS differentiation mechanisms for OBS is given and their efficiency and complexity are comparatively discussed. We provide numerical examples on how QoS differentiation with respect to burst loss rate and transport layer throughput can be achieved in OBS networks. © 2009 Elsevier B.V. All rights reserved

    Deflection Routing Strategies for Optical Burst Switching Networks: Contemporary Affirmation of the Recent Literature

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    A promising option to raising busty interchange in system communication could be Optical Burst Switched (OBS) networks among scalable and support routing effective. The routing schemes with disputation resolution got much interest, because the OBS network is buffer less in character. Because the deflection steering can use limited optical buffering or actually no buffering thus the choice or deflection routing techniques can be critical. Within this paper we investigate the affirmation of the current literature on alternate (deflection) routing strategies accessible for OBS networks

    Burst switched optical networks supporting legacy and future service types

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    Focusing on the principles and the paradigm of OBS an overview addressing expectable performance and application issues is presented. Proposals on OBS were published over a decade and the presented techniques spread into many directions. The paper comprises discussions of several challenges that OBS meets, in order to compile the big picture. The OBS principle is presented unrestricted to individual proposals and trends. Merits are openly discussed, considering basic teletraffic theory and common traffic characterisation. A more generic OBS paradigm than usual is impartially discussed and found capable to overcome shortcomings of recent proposals. In conclusion, an OBS that offers different connection types may support most client demands within a sole optical network layer

    Optical Networks for Future Internet Design

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    Improving Routing Efficiency, Fairness, Differentiated Servises And Throughput In Optical Networks

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    Wavelength division multiplexed (WDM) optical networks are rapidly becoming the technology of choice in next-generation Internet architectures. This dissertation addresses the important issues of improving four aspects of optical networks, namely, routing efficiency, fairness, differentiated quality of service (QoS) and throughput. A new approach for implementing efficient routing and wavelength assignment in WDM networks is proposed and evaluated. In this approach, the state of a multiple-fiber link is represented by a compact bitmap computed as the logical union of the bitmaps of the free wavelengths in the fibers of this link. A modified Dijkstra\u27s shortest path algorithm and a wavelength assignment algorithm are developed using fast logical operations on the bitmap representation. In optical burst switched (OBS) networks, the burst dropping probability increases as the number of hops in the lightpath of the burst increases. Two schemes are proposed and evaluated to alleviate this unfairness. The two schemes have simple logic, and alleviate the beat-down unfairness problem without negatively impacting the overall throughput of the system. Two similar schemes to provide differentiated services in OBS networks are introduced. A new scheme to improve the fairness of OBS networks based on burst preemption is presented. The scheme uses carefully designed constraints to avoid excessive wasted channel reservations, reduce cascaded useless preemptions, and maintain healthy throughput levels. A new scheme to improve the throughput of OBS networks based on burst preemption is presented. An analytical model is developed to compute the throughput of the network for the special case when the network has a ring topology and the preemption weight is based solely on burst size. The analytical model is quite accurate and gives results close to those obtained by simulation. Finally, a preemption-based scheme for the concurrent improvement of throughput and burst fairness in OBS networks is proposed and evaluated. The scheme uses a preemption weight consisting of two terms: the first term is a function of the size of the burst and the second term is the product of the hop count times the length of the lightpath of the burst
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