Review #7: Analysis and simulation of a fair queueing algorithm

From: Rosalia Tungaraza (rltungar@u.washington.edu)
Date: Sun Oct 24 2004 - 23:29:44 PDT

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    This paper is about a modification of Nagle's fair-queuing (FQ)
    algorithm used in routers to
    separate packets according to the flow they belong to. Moreover, this
    algorithm uses a round robin like technique to propagate those packets to
    the next link in the network. FQ serves mainly as a congestion control
    mechanism, which can be used with various packet-dropping algorithm to
    complete that job.

    I think one of the successes of this algorithm is that it can both detect
    misbehaving users (hosts
    who are trying to monopolize the buffers present within a given router and
    bottleneck links) and punish/discourage them when they do so. It does that
    by offering a separate queue for every flow in the network. Hence, any
    flow that sends more packets than what it is supposed to within any given
    time period will have its packets dropped. That particular flow will also
    be penalized (or charged).

    One thing that I would have liked the authors to discuss more is how
    their FQ
    could be used to deal with issues of Quality of Service. Even though, they
    pointed to this issue towards the very end of the paper, I am still
    wondering how efficient this algorithm would be if a router was faced with
    more than one flow from an intolerant real time application. On the other
    hand, QoS in relation to FQ might be a topic that is beyond the scope of
    this paper.

    As the authors suggest future work in this area could be geared towards
    finding out whether one could build FQ gateways that can match the
    bandwidth of fibers and if so whether those gateways would be economically
    feasible.


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