A case for evaluating backpressure routing using Ns-3 emulation in a WiFi mesh testbed

Rapid prototyping of wireless network protocols is a recurring problem faced by experimental researchers. This feature is one of the biggest assets of the ns-3 emulation functionality. This paper provides the experimental evaluation of a novel distributed backpressure routing protocol implemented in ns-3 simulator exploiting the ns-3 emulation framework in a 12-node WiFi mesh network testbed. In this case in particular, the management of data queues present both in the ns-3 at application space and real WiFi cards at kernel space is a key issue for the correct operation of the routing protocol in the testbed. We introduce a mechanism based on Netlink sockets and the /sys subsystem to schedule the interaction and share information between data queues in ns-3 at user space and kernel space. A set of experiments characterizing the testbed and comparing results with the ns-3 simulator show that the ns-3 emulation framework augmented with the use of Netlink sockets and the /sys subsystem communication methods do not introduce performance degradation in terms of throughput. In addition, extensive evaluation results demonstrate the correct operation of the backpressure routing protocol in the WiFi mesh testbed, indicating the convenience of using ns-3 for the evaluation of wireless network protocols for both simulation and experimental methodologies.