## 7 Result and Discussion
### RQ6: What Are the Existing Threats in RPL-Based 6 LoWPAN That the Existing Studies Had Addressed?
#### 7.6.2 Topology-Based Attacks  
* **Selective Forwarding (SF) Attack:** This attack happens when the malicious node dislocates the network routing path by selectively forwarding some of the packets in the network while leaving the rest forwarded to the original destination [21]. In addition, this attack can involve one or more malicious nodes and could either be consecutive or non-consecutive [23].
* **DIO Suppression Attack:** The purpose of the DIO suppression attack is to disrupt or slow down the network's transmission of DIO messages. For this purpose, [PERSON]'s DIO suppression method is used. During this attack, the adversary continuously sends a DIO message that the receiving nodes regard as consistent. Suppose the nodes get a sufficient number of consistent DIOs. In that case, they disable their own DIO transmission, resulting in a general decrease in the quality of the routes or, in the worst-case scenario, a network breakdown [62,78].
* **Worst Parent (WP) Attack:** In the WP attack scenario, the attacker fabricates routing information and broadcasts DIO messages to neighboring nodes with different rank values than genuine ones. Later, the child node assigns the malicious node (with the highest rank value) as their parent instead of the best ones specified in the usual RPL scenario. As a result of this attack, the network nodes suffer from non-optimal routing paths, degrading their performance and leading to high consumption of power resources [3,24].
* **Opportunistic Service Attack:** In this attack, the malicious node gains its trust value by initially offering highly dependable services and then later resorts to providing inferior services for its own sake [63].
* **Temperature Level Attack:** The attacker manipulates the reading of the temperature and humidity level sensors in patients' rooms. Consequently, the air-conditioning system stabilizes the temperature level based on erroneous data, which could cause deterioration of the patient's health [7].
* **Heart Attack:** This is an e-health related data attack that manipulates the patient's heartbeat level information. Such modifications might cause bad decisions being made or ignored by emergency personnel, such as when a patient's heart rate is extremely low/high and quick medical attention is required [7].
* **WormHole (WH) Attack:** In a WH attack, two or more attackers collaborated to establish a virtual tunnel between them to pass the traffic, entirely or selectively, through it instead of its original route. Therefore, such an attack disrupts the network topology, exhausts network resources, and provides the attackers with access to sensitive information [69; 79].
* **SinkHole (SH) Attack:** A malicious node broadcasts itself as the best convenient route (optimal path) to be a preferred parent for the surrounding nodes. Then, the network traffic of the child nodes will be forwarded to the SH node. Therefore, this attack disrupts the communication and leads to other kinds of attacks [32; 49; 80].
* **BlackHole (BH) Attack:** In a BH attack, the pernicious node announces itself as the shortest route to the destination. All the packets arriving at this node will be dropped and, thus, prevented from reaching their destinations. Therefore, this attack will create a 'hole' in the network without the senders being aware of their packets' delivery status [49; 63].