## 4 Related Work  
As discussed in the previous section, RPL comes with different basic security modes but has no sufficient security support against internal routing attacks. Although secure access control can be provided using the authentication mode, there is still a great opportunity for a node to be compromised and used for initiating internal routing attacks. The inherent protocol design of RPL makes it easy to initiate common routing attacks such as the sinkhole, blackhole, and wormhole attacks [13; 26; 27] in addition to the RPL-specific ones such as VN, replay, and WP attacks [28; 29]. The different potential RPL security attacks have been surveyed and reviewed in different research studies [14; 15; 16; 17; 18]. In these works, a classification of the RPL attacks into those targeting network topology, network resources, and network traffic was provided. An example of a network topology attack is the WP attack whereas the VN and rank attacks were categorized as network resource attacks. In addition, there have been various research efforts made to study the performance of RPL networks under a specific routing attack. The overall results showed that these attacks result in considerable overall performance degradation of the targeted RPL networks. The experimental results presented in [30] demonstrated how RPL networks experienced a high delay, packet loss, and network overhead when being under blackhole attacks. The experimental study in [31] showed the adverse impact of the wormhole attack on the power consumption and network overhead of RPL networks. The same attack was investigated in [32] over a real-testbed setup. The results illustrated the ability of the attack to cause high increases in packet loss. The experimental study in [33] discussed the adverse impact of the sinkhole attack on RPL compared to other protocols such as AODV. The attack led to a degradation of QoS performance and increases in network overhead and energy consumption as indicated by the presented simulation results. The study presented in [34; 35] showed that DIS flooding attacks can decrease PDR and increase delay and power consumption, particularly in composite-attack scenarios. Experimenting with RPL networks using real-testbed setups in [36], similar results showing that DIS flooding attack degraded power consumption in addition to nodes' joining time were presented. In [37], the DAO induction attack caused a noticeable degradation of QoS performance and led to high increases in communication delay and packet loss. In [38], the impact of single and composite replay attacks on RPL networks was experimentally examined. As the results indicated, the attacks led to a high degradation of QoS performance and an increase in energy consumption. The VN attack was investigated in different research studies for examining its effect on RPL networks. The simulation results in [39] indicate how the VN attack can result in a noticeable drop in PDR in addition to a high increase in delay and network overhead. High power consumption can also be incurred by VN attacks as demonstrated by the evaluation results in [40; 41]. Moreover, a more effective VN attack can be launched with multiple nodes performing the attack simultaneously in a distributed manner. The experimental results in [42] show that increasing the number of attackers amplified the adverse effect of the VN attack. Other studies showed that the RPL network experienced more adverse impacts of VN attacks as the network was flooded by these attacks [43] and when the network had mobile nodes [44]. The rank attack was also experimentally studied in [45] considering different network topology structures. The evaluation results showed that the attack affected the overall performance of RPL networks in all the considered scenarios as the energy consumption and network overhead noticeably increased. In [46], it was observed that targeting large-scale RPL networks with composite rank attacks can noticeably lead to high degradation of QoS performance.