Using asymmetric links to improve SSR´s routing performance

Empirical evidence shows that asymmetric links occur frequently in wireless networks. Still, most routing protocols assume symmetric links. Thus, they cannot exploit the additional connectivity and bandwidth that asymmetric links provide. In this paper, we propose an extension of the scalable source routing protocol (SSR) that enables SSR to use asymmetric links. It enhances SSR´s hello messages with a limited amount of local topology information, which allows the nodes to discover directed cycles in the network. Such cycles provide a return path in cases where the forward path contains asymmetric links. With our proposed extension, SSR can thus use asymmetric links and still guarantee bidirectional connectivity. We evaluate our proposals with extensive simulations. A practical test in a 150 node test bed is ongoing work.