K-directory community: Reliable service discovery in MANET

Service discovery in MANET suffers from frequent service unavailability due to failures of service providers or directory nodes. Ensuring network-wide service availability by replication requires minimizing costs associated with storage, update and discovery. Existing works in MANET have not addressed these challenging issues adequately. In this paper, we propose a distributed directory-based service discovery protocol (SDP) for MANET. Our protocol works by electing top K nodes with rich resources as directories, which are then divided into multiple quorums. Services registered with a directory are replicated among its quorum members. This approach reduces replication and update costs, and guarantees network-wide service availability using the quorum intersection property. An incremental election policy is adopted to cope with directory failures. We have carried out extensive simulations and also developed a prototype system. Our performance evaluation results show that, compared with similar work, our protocol significantly reduces message cost and improves system robustness.