Toward Resilient Routing in Wireless Sensor Networks: Gradient-Based Routing in Focus

This paper focuses on the resiliency of wireless sensor network routing protocols against selective forwarding attacks by compromised nodes. To provide for security in such a context cryptographic solutions must be completed by algorithmic solutions considering "beyond cryptography" approaches. Enhancing the routing protocol resiliency to attacks is one approach that merits further investigation. In a sense, resiliency to compromised nodes enhances the reliability of sensor networks. In this article, after discussing the shortcomings of existing routing protocols against packet-dropping malicious nodes we describe some protocol behaviors enhancing resiliency in this particular context. These behaviors are mainly based on traffic redundancy and probabilistic selection for the next hop candidates which permit to exploit and benefit from the inherent structural redundancy of densely deployed sensor networks. Several variants of the well known gradient-based routing protocol were tested and simulation results show that using the proposed strategies resiliency can be improved. The results also shed some light on the resiliency-energy consumption trade-off.