Evaluation of RPL with a transmission count-efficient and trust-aware routing metric

Wireless Sensor Networks (WSNs) often need to operate under strict requirements on energy consumption and be capable of self-adapting to the presence of non-trusted nodes which do not fully cooperate in the packet forwarding operation. In such an environment, the mechanism employed for the calculation of routing paths of minimum cost in terms of the number of transmissions executed for the reliable communication between the data source and the data sink is essential to prevent unnecessary nodes´ energy depletion and help prolong the network´s lifetime. In this paper, we study a routing metric, TXPFI, that captures the expected number of frame transmissions - including retransmissions - needed for the successful delivery of data from the source to the destination in the presence of malicious nodes and lossy links, and validate its applicability to the IETF RPL routing protocol. Through extensive simulations we evaluate the capability of TXPFI to compute routing paths of minimum transmission count and compare it against a number of metrics suitable for transmission count-efficient and trust-aware routing in WSNs. The results show that the use of TXPFI in RPL can lead to significant transmission count savings.