Pushing Chord into the Underlay: Scalable Routing for Hybrid MANETs

SCALABLE SOURCE ROUTING is a novel routing approach for large unstructured networks, for example hybrid mobile ad hoc networks (MANETs), mesh networks, or sensor-actuator networks. It is especially suited for organically growing networks of many resource-limited mobile devices supported by a few fixed-wired nodes. SCALABLE SOURCE ROUTING is a full-fledged routing protocol that directly provides the semantics of a structured peer-to-peer overlay. Hence, it can serve as an efficient basis for fully decentralized applications on mobile devices. SCALABLE SOURCE ROUTING combines source routing in the physical network with Chord-like routing in the virtual ring formed by the address space. Message forwarding greedily decreases the distance in the virtual ring while preferring physically short paths. Unlike previous approaches, scalability is achieved without imposing artificial hierarchies or assigning location-dependent addresses. SCALABLE SOURCE ROUTING enables any-to-any communication in a flat address space without maintaining any-to-any routes. Each node proactively discovers its virtual vicinity using an iterative process. Additionally, it passively caches a limited amount of additional paths. By means of extensive simulation, we show that SCALABLE SOURCE ROUTING is resource-efficient and scalable well beyond 10,000 nodes. A MIPSLinux version demonstrating the real-world feasibility of SCALABLE SOURCE ROUTING is available. ∗Supported by Deutsche Forschungsgemeinschaft under grant FU448-1.