Retarding application idle timer expiration for service resumption in challenged network

In challenged network environments like tunnels, a mobile node can suffer from a sudden disruption in mobile services, e.g., the abrupt ending of an application session, due to factors like coverage holes. To tackle this issue, there is an approach that provides tolerance for disruptions or disconnections in the network architecture, in which proxy functions in the network and the mobile node conceal the disruption of the wireless link from users and application servers. After the wireless link is re-established, the services the user enjoys are resumed. However, even if such a disruption-tolerant function avoids the direct negative effects of a disruption, i.e., the sudden end of an application session, the services could still end due to an application idle timer. In this paper, we propose a dynamic buffering method, named application idle timer retardation buffering (ARB), to deal with the application idle timeout issue. The proxy function in a mobile node has a buffer for incoming data from the network and queues data for only a brief moment before forwarding it to an application. When link connectivity is lost, the proxy function forwards queued data to the end-user application at a very low rate in order to delay application idle timer expiration by repeatedly resetting the timer. We implemented ARB in PCs and conducted field tests. The results of the ARB field test indicate that ARB maintains continuity despite communication interruptions as much as eleven times longer than could be handled without it, without throughput degradation.