MOPS: Providing Content-Based Service in Disruption-Tolerant Networks

Content-based service, which dynamically routes and delivers events from sources to interested users, is extremely important to network services. However, existing content-based protocols for static networks will incur unaffordable maintenance costs if they are applied directly to the highly mobile environment that is featured in disruption-tolerant networks (DTNs). In this paper, we propose a unique publish/subscribe scheme that utilizes the long-term social network properties, which are observed in many DTNs, to facilitate content-based services in DTNs. We distributively construct communities based on the neighboring relationships from nodes' encounter histories. Brokers are deployed to bridge the communities, and they adopt a locally prioritized pub/sub scheme which combines the structural importance with subscription interests, to decide what events they should collect, store, and propagate. Different trade-offs for content-based service can be achieved by tuning the closeness threshold in community formation or by adjusting the broker-to-broker communication scheme. Extensive real-trace and synthetic-trace driven simulation results are presented to support the effectiveness of our scheme.