DisGB: Using Geo-Context Information for Efficient Routing in Geo-Distributed Pub/Sub Systems

IoT data are usually exchanged via pub/sub, e.g., based on the MQTT protocol. Especially in the IoT, however, the relevance of data often depends on the geo-context, e.g., the location of data source and sink. In this paper, we propose two inter-broker routing strategies that use this characteristic for the selection of rendezvous points. We evaluate analytically and through experiments with a distributed pub/sub prototype which strategy is best suited in three IoT scenarios. Based on simulation, we compare the performance and efficiency of our approach to the state of the art: Our strategies reduce the event delivery latency by up to 22 times compared to the only alternative that sends slightly fewer messages. Our strategies also require significantly less inter-broker messages than all other approaches while achieving at least the same performance.