Xenia Mountrouidou

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We propose and analyze a novel discrete-time queueing network model of a zero loss hub-based Optical Burst Switched (OBS) architecture, consisting of multiple input edge nodes and one destination edge node. The arrival process of bursts is slotted with bulk arrivals as generated by a Time and Burst-Length based burst aggregation algorithm. The queueing(More)
We describe an efficient and accurate approximation method for calculating the bandwidth that should be allocated on each link along the path of a point-to-point MPLS connection, so that the end-to-end delay D is less than or equal to a given value T with a probability γ, that is, P(D≤T) = γ. We model a connection by a tandem queueing network of infinite(More)
We describe an analytic approach for the calculation of the departure process from a burst ggregation algorithm that uses both a timer and maximum/minimum burst size. The arrival process of packets is assumed to be Poisson or bursty modelled by an Interrupted Poisson Process (IPP). The analytic results are approximate and validation against simulation data(More)
Software-defined networking (SDN) and Open Flow have been driving new security applications and services. However, even if some of these studies provide interesting visions of what can be achieved, they stop short of presenting realistic application scenarios and experimental results. In this paper, we discuss a novel attack detection approach that(More)
Performance studies point to the fact that in an OBS network, the link utilization has to be kept very low in order for the burst loss probability to be within an acceptable level. Various congestion control schemes have been proposed, such as the use of converters, fiber delay lines, and deflection routing. However, these schemes do not alleviate this(More)
We propose and evaluate a novel scheme, referred to as Bimodal Burst Switching (BBS) scheme, for Optical Burst Switching (OBS) star networks, which can be used in Grid networks. The main feature of this scheme is that it has zero burst loss and a large geographical coverage. Using simulation techniques we show that the proposed scheme provides high(More)
We present a robust framework that aims at harvesting future idle intervals for power savings within strict constraints: first, it is imperative to contain the delays in service of IO requests that occur during power savings since the time to bring up the disk is not negligible and second, ensure that the power saving mechanism is triggered few times only,(More)
We characterize analytically the departure process from the following three burst aggregation algorithms: the time based aggregation algorithm, the burst-length based aggregation algorithm and the time and burst-length based aggregation algorithm. The arrival process of packets is assumed to be Poisson or bursty modeled by an Interrupted Poisson Process(More)
Software Defined Networking (SDN) has the potential to enable novel security applications that support flexible, on-demand deployment of system elements. It can offer targeted forensic evidence collection and investigation of computer network attacks. Such unique capabilities are instrumental to network intrusion detection that is challenged by large(More)
In order to reduce the amount of power consumption in data centers, it is becoming necessary to shut off or slow down disks that are not actively serving user requests. In addition to exploiting disk drive idleness, system features are in place that shape a disk's workload by redirecting portions of it elsewhere, with the goal to expand the periods of(More)