Summary: An Experimental Study of New and Known Online Packet
We present the first experimental study of online packet buffering algorithms for network switches.
The design and analysis of such strategies has received considerable research attention in the theory
community recently. We consider a basic scenario in which m queues of size B have to be main-
tained so as to maximize the packet throughput. A Greedy strategy, which always serves the most
populated queue, achieves a competitive ratio of only 2. Therefore, various online algorithms with
improved competitive factors were developed in the literature.
In this paper we first develop a new online algorithm, called HSFOD, which is especially designed
to perform well under real-world conditions. We prove that its competitive ratio is equal to 2.
The major part of this paper is devoted to the experimental study in which we have implemented
all the proposed algorithms, including HSFOD, and tested them on packet traces from benchmark
libraries. We have evaluated the experimentally observed competitivess, the running times, memory
requirements and actual packet throughput of the strategies. The tests were performed for varying
values of m and B as well as varying switch speeds. The extensive experiments demonstrate that
despite a relatively high theoretical competitive ratio, heuristic and greedy-like strategies are the
methods of choice in a practical environment. In particular, HSFOD has the best experimentally