BOSAM: A Tool for Visualizing Topological Structures Based on the Bitmap of Sorted Adjacent Matrix

Though the adjacent matrix is a representation of a topology, it does not tell the topological structures explicitly. A visualization tool which can represent topological structures explicitly is desired for model validation or measurements comparison. However, displaying nodes and links directly in a space as a routine is ineffective for massive topologies, like that of Internet. Instead, researchers have recourse to various statistical metrics extracted from the adjacent matrix. Such a statistical metric often reflects only a single aspect of the topology but at the cost of burdensome computation. In this paper a novel simple visualization tool based on displaying the Bitmap of Sorted Adjacent Matrix, BOSAM, is proposed to fill the gap. Validations of AS-level topology models and comparisons of topology measurements are provided to show that BOSAM works efficiently. The bitmap displaying can avoid messy cross lines and make the correlation between nodes stand out. The rules of sorting node indexes can be defined flexibly to expose diverse topological structures. Moreover, some fractal features in the AS graphs or generated graphs, which are not easily to be covered by statistical analysis, can be exposed explicitly as well. Parting from the huge burden of statistical computation, BOSAM can be realized easily.