• distributed communication system;
  • peer-to-peer;
  • DHT;
  • Comb;
  • two-hop


Communication systems utilize the distributed hash table (DHT) approach to build the network infrastructure for advantages of even distribution of workload, high scalability, and cost-effectiveness. Although DHT is undoubtedly applicative in such architectures, some practical distinctions still should be considered to meet the performance requirements of communication infrastructures. This paper focuses on two features of the distributed communication system, the real-time response and dynamic network maintenance, and proposes the Comb, which is a hierarchical DHT lookup service. Comb's overlay is organized as a two-layered architecture, workload is distributed evenly among nodes, and most queries can be routed in no more than two hops. Comb is capable to scale to large systems and resilient to fluctuate, it provides a self-managing and self-healing mechanism for supporting system recovery from inconsistence. Comb performs effectively with low bandwidth consumption and satisfactory fault tolerance even in a continuously changing environment. Both theoretical analyses and experimental results demonstrate that the two-layered architecture of Comb is resilient and efficient. Comb improves the performances on routing delay and lookup failure rates with high scalability and availability. Copyright © 2014 John Wiley & Sons, Ltd.