Constructing Overlay Networks with Low Link Costs and Short Paths

In overlay networks, which are virtual networks for P2P applications, topology mismatching is known as a serious problem to be solved. So far several distributed algorithms have been proposed to reduce link cost caused by this problem. However, they often create long routes with a large number of hops, especially for long distance communications. In this paper, we propose a distributed algorithm to address this issue. This algorithm designates nodes in an overlay network as special nodes with some probability. A special node iteratively exchanges one of its links with a new, longer distance link, instead of a shorter one. The new links are extensively used for long distance communications. The simulation studies show that in the overlay networks constructed by this algorithm, the number of hops per route is reduced for long distance communications, at the cost of a slight increase in link cost.