A queuing mechanism for delivering QoS-constrained web services in tactical networks

This paper describes a hierarchical queuing mechanism designed to monitor and control radio buffers while delivering web services in tactical networks. Our solution was motivated by the restrictions imposed by VHF radios, which have large coverage (~20 km) but very low data rate (e.g. up to 9.6 kbps). Therefore we implemented two queues, one for messages (Qm) and another for IP packets (Qp), shaping the user-generated data traffic to avoid buffer overflow. The queues complement each other, behaving like control points in a feedback loop. Both control points use the current radio buffer occupancy to decide when to dequeue messages and IP packets. We studied the performance of a prototype in a testbed using real military radios with focus on two variations of our control mechanism (reactive/proactive). The quantitative analysis shows our queuing mechanism successfully avoiding buffer overflow under challenging network conditions.