Subscriber Mobility in Pub/Sub Systems: Pro-active vs. Reactive Handoffs

To support mobile subscribers in pub/sub systems, existing approaches are mainly based on reactive methods (i.e., the message transfer occurs just after the mobile subscriber handoffs to a new broker). In this paper, we analyze a novel and efficient mobility extension based on a pro-active approach (i.e., the context transfer/caching occurs prior to the subscriber movement). We implemented both reactive and pro-active mobility extensions for JMS and conducted a range of experiments in a small testbed to compare the relative merits of each approach. Our experimental results show that a pro-active approach can provide fast handoff support with zero duplicated messages. It also achieves relatively higher throughput results and lower message loss compared to the reactive approach.