Churn Resilience of Distributed Content Service System on Smart Terminals Network

Recently, the content service system is shifting from a centralized model to distributed model with the capabilities of terminal devices increasing. In addition to providing service to local users, the smart terminals utilize unused bandwidth and storage resources to provide proximity services to neighbor terminals in the overlay network. How to ensure the performance of the distributed system with the continuous process of terminals joining or leaving the overlay network (churn) is a crucial issue. Existing strategies maintain the system’s service under churn through the central server scheduling or constructing complex topology. In this paper, we propose a hierarchical topology for terminals network. The inter-cluster and intra-cluster overlay use the unstructured network. The connectivity of topology is easy to be maintained under the churn. Further, we offer a decentralized replications diffusion and maintenance mechanism on the topology. Under the churn of terminals, the number of replications can be maintained autonomously to a reasonable amount. In the ordinary churn, the success rate of services in our network only drops by about 9% and is well kept. The mechanism can also quickly restore the performance of the network under the extremely churn.