Grid Job Routing Algorithms - Phosphorus

Grid Job Routing AlgorithmsSTARLIGHT CESNET 8790STARLIGHT SURFnet 7980STARLIGHT CRC 1250CRC PSNC 8570Table 5-1: Network connections for simulations5.2.1 Multi-domain networksThe network considered in multi-domain routing consists of the core network depicted in Figure 5.3 enlargedwith local networks at every core switch. These local networks are generated using the Barabási-Albert (BA)algorithm. The BA algorithm is based on two generic mechanisms [Barabasi99]:1. growth: networks expand continuously by the addition of new vertices.2. preferential attachment: new vertices attach preferentially to sites that are already well connected.The algorithm works as follows: we start with a small number ( m ) of vertices, at every time step we add a new0vertex with m( ≤ m ) edges that links the new vertex to m different vertices already present in the network. To0incorporate preferential attachment, we assume that the probability Π that a new vertex will be connected tokivertex i depends on the connectivity k of that vertex, so that Π ( k ) = . After t time steps, the model leadsii∑ kto a random network with t + m vertices and mt edges. This network evolves into a scale-invariant state with0the probability that a vertex has k edges, following a power law ( K − γ) with an exponent γ = 2.9 ± 0.1 . Thismodalgorithm has been proposed in [Barabasi99] to model complex networks like the World Wide Web and thenervous system.jjelProject:PHOSPHORUSDeliverable Number: D.5.3Date of Issue: 31/06/07EC Contract No.: 034115Document Code: Phosphorus-WP5-D5.349