DATEM: Towards QoS Aware Event Notification Framework for Delay Tolerant Networks

Delay tolerant networks (DTNs), which are wireless networks prone to long delays and frequent disruptions are increasingly becoming common. We are exploring the challenges involved in designing effective event notification framework on DTNs. This paper presents the design and evaluation of a delay-tolerant event notification framework called DATEM based on the philosophy that failures and delays are too common to be effectively masked from applications. DATEM represents a comprehensive redesign of traditional event routing mechanisms and system management techniques. First, the framework exposes the delay- and failure-prone nature of the underlying network to the applications via an enhanced set of API and let them handle these parameters in an application specific manner. Second, it incorporates a novel event routing protocol that enables the nodes of the delay tolerant network to collaboratively achieve QoS requested by the applications. Third, a utility-aware event prioritization scheme is designed to prioritize event-packets that have the largest impact on the performance of DATEM framework. Our experimental study shows that DATEM provides significant performance benefits when compared with traditional event notification schemes.