Supporting mobility with persistent notifications in publish/subscribe systems

The paper proposes a novel approach to mobility in publish/subscribe (pub/sub) systems that relies on notification persistency. The existing solutions apply proxy subscribers that take the role of disconnected subscribers, store notifications published during disconnections, and deliver them to subscribers after reconnection to the pub/sub system. The system perceives a constant number of subscribers which is inefficient if it serves a large number of subscribers that are often disconnected. We argue that the system should not be burdened by proxy subscribers during subscriber disconnections, but rather store persistent notifications, and deliver valid notifications to subscribers when they reconnect to the system. Preliminary experiments show that the proposed solution can improve the observed scalability weakness of the existing solutions.