Mesh-DHT: A locality-based distributed look-up structure for Wireless Mesh Networks

Distributed Hash Tables (DHTs) offer an elegant and fully distributed solution for reliably storing and retrieving data. Wireless Mesh Networks (WMNs) envision a fully decentralized fashion, and as such require efficient decentralized mechanisms for service discovery, mobility support and data storage and retrieval. Hence, DHTs and WMNs seem to complement each other nicely and even share common traits and challenges, such as multi-path routing and dynamic membership of unreliable nodes. Existing Internet-based DHT approaches are designed to emphasize performance and stability in Internet scenarios and do not consider the special conditions in WMNs. In particular, they do not focus on the impact of the physical neighbor relations of DHT nodes and assume efficient global connectivity. In contrast, in a WMN, locality of communication is essential to avoid unnecessary multi-hop data transmissions and congestion on the wireless link. We present Mesh-DHT, an approach for building a scalable DHT in WMNs that puts special emphasis on the locality of nodes and links. We construct a stable, location-aware overlay network that enables fully distributed organization of information. By design, our DHT geometry is closely aligned to the network topology of the WMN to emphasize local communication. We show that our approach preserves locality in the overlay construction, is robust against node failure, and makes efficient use of local information. These properties make our approach scalable even in the presence of hundreds of mesh nodes.