The literature contains propositions for the use of overlay networks to supplement the normal IP routing functions with higher-level information in order to improve network-behavior aspects. We consider the use of such an overlay to optimize the end-to-end behavior of some special traffic flows. Measurements are used both to construct the virtual links of the overlay and to establish the link costs for use in a link-state routing protocol. The overlay attempts to forward certain packets over the least congested rather than the shortest path. We present simulation results showing that, contrary to common belief, overlay networks are not always beneficial and can be detrimental. The main aspects and circumstances influencing the behavior of overlay networks are identified.
By: Ilias Iliadis, Daniel Bauer, Sean Rooney, Paolo Scotton, and Sonja Buchegger
Published in: RZ3492 in 2003
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