Xenia Mountrouidou

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— 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)
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 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 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 Pois-son Process (IPP). The analytic results are approximate and validation against simulation data(More)
We characterize analytically the departure process from the following three burst ag-gregation 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)
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 obtain analytically the delay per packet in a burst for the three burst aggregation algorithms: Time based, Burst Length based and mixed Time and Burst Length based, assuming real video and aggregated Internet traces, as well as the IPP arrivals. For video traces we also obtain the probability that a playback machine will pause due to lack of frames when(More)
The biggest power consumer in data centers is the storage system. Coupled with the fact that disk drives are lowly utilized, disks offer great opportunities for power savings, but any power saving action should be transparent to user traffic. Estimating correctly the performance impact of power saving becomes crucial for the effectiveness of power saving.(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)
With most of today's systems being highly distributed, from data centers to cloud and storage clusters, there is a prevalent need for robust methodologies for work consolidation to improve load balancing but also to optimize non-traditional performance measures. Such alternative measures may include power savings, e.g., it may be desirable to shut down a(More)