Institute for Systems Research

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Author: search.filters.author.Baras, John S.Subject: search.filters.subject.queueing

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    Fair Bandwidth Allocation and Buffer Management in Hybrid Network Gateways
    (2000) Srinivasan, Roshni; Vaidyanathan, Ravichander; Baras, John S.; Baras, John S.; ISR; CSHCN
    In this paper, we present an efficient and fair resource allocationscheme for scheduling and buffer management in a bottleneck hybridsatellite-terrestrial network gateway with per-flow TCP queues.

    Ourfirst contribution is the use of Fair Queueing in conjunction withProbabilistic Fair Drop, a new buffer management policy to allocatebandwidth and buffer space in the gateway, to ensure that all TCPflows threading the gateway achieve high end-to-end throughput andfair service.

    Our second contribution is to introduce the concept ofbuffer dimensioning to alleviate the inherent bias of the TCPalgorithm towards connections with large Round Trip Time.

    In supportof each of these contributions, we report on extensive simulationresults. Our scheme outperforms other resource allocation schemesreported in the literature and in particular, demonstrates significantimprovements in fairness to long RTT connections in the hybrid networkframework.

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    Window Distribution of Multiple TCPs with Random Loss Queues
    (1999) Misra, Archan; Baras, John S.; Ott, Teunis; Baras, John S.; ISR; CSHCN
    In this paper, we consider the case of multiple ideal and persistent TCP flows (flows that are assumed to be performing idealized congestion avoidance) interacting with queue management algorithms that perform random drop-based buffer management. Our objective is to determine the stationary congestion window distribution of each of the TCP flows whenthe router port implements algorithms like RED (Random Early Detection)or ERD (Early Random Drop).

    We first present an analyticaltechnique to obtain the 'mean' queue occupancy and the 'mean' of the individual TCP windows. Armed with this estimate of the means, wethen derive the window distribution of each individual TCPconnection. Extensive simulation experiments indicate that, under a wide variety of operating conditions, our analytical method is quite accurate in predicting the 'mean' as well asthe distributions. The derivation of the individual distributions is based upon a numerical analysis presented which considers the case of a single TCP flow subject to variable state-dependent packet loss.