Continuous Query-Based Syndication: Distributed, Expressive Messaging for the IoT

Applications in the Internet of Things exist at a confluence of semantically isolated networks over buildings, physical spaces, cloud services, smart appliances and mobile and wearable devices. The utility of these applications is in their ability to capture capabilities of new families of smart, networked devices and integrate them with existing networks surrounding people, things and places. We present a novel publish-subscribe mechanism—continuous query-based syndication (CQBS)—that allows subscribers to richly describe the set of resources they require and maintain a consistent view of relevant data sources even as they change over time. We implement a highly available, distributed CQBS broker that uses a replicated coordinator to provide simple failover for embedded clients. Through benchmarks, we demonstrate that the system maintains reasonable 95 percentile latencies of under 10ms even under load.