Owing to high flexibility and connectivity, RPL communication is exploited in the majority of IoT applications. However, security is the critical concern faced by RPL based IoT applications. The heterogeneous and resource-limited IoT characteristics are vulnerable to several types of RPL attacks.

   Some of the RPL-IoT attacks are replay, DODAG Information Solicitation (DIS), Sybil, version number, rank, neighbor attack, hello flood, selective forwarding, sinkhole, black hole, wormhole, routing choice intrusion, and DIO specific attacks. The attackers aim to increase the delay, power consumption, and overhead in the network. The main intention of RPL routing attacks is to disrupt the normal routing functions and degrades the network performance by launching any of the abovementioned malicious activities into the network.

   Many defense schemes are introduced in the literature to neglect the impact of such attacks on RPL performance. The defense strategies are majorly categorized into three categories that are cryptography based, trust-based, game theory-based, Intrusion Detection System (IDS) based, and learning-based.