## 2 Motivation and Related Works  
The RPL standard [1] defines the generation and management of destination-oriented DAG (DODAG), which is a tree-based routing topology in IPv6 wireless sensor networks. Moreover, it supports multipoint-to-point, point-to-multipoint and point-to-point data transmission based on DODAG. RPL builds an entire topology graph by using three different ICMPv6-based control messages: DIO (DODAG information object), DAO (DODAG destination advertisement object) and DIS (DODAG information solicitation). In RPL, the creation and management of a DODAG starting from the DODAG root are achieved through the transmission of DIO messages. The DODAG root creates a DODAG and spreads the DODAG information to the nodes in the network through the transmission of DIO messages. Nodes that receive a DIO message participate in the DODAG and generate an upward path toward the DODAG root. The routers in the network that are capable of broadcasting allow for the other nodes to participate in the DODAG by transmitting DIO messages. The nodes that are currently participating in DODAG generate a downward path using DAO messages. DIS is used to solicit DIO messages from router nodes in RPL. DIS may be used to probe neighbor nodes in adjacent DODAGs. After receiving the DIO messages, the new node then selects one or more parent nodes using the objective function (OF). The trickle algorithm in RPL is used to maintain consistency in a network by using control messages [2]. The trickle algorithm reduces energy consumption by avoiding duplicate messages between nodes. For this purpose, the trickle algorithm exchanges information with network nodes in a highly robust, energy efficient, simple and scalable manner. The trickle algorithm rapidly detects changes in the network topology and adjusts the network to a consistent state using only a few control messages per hour after the network topology is stabilized. The simple suppression mechanism and transmission point selection used in the trickle algorithm are based on simple rules rather than a complicated synchronization scheme between nodes. Owing to these characteristics, even with a linear increase in the number of nodes, the overall traffic increases logarithmically. A trickle timer governs the transmission of control messages for adjusting the network to a consistent state. The timer controls the inconsistencies in an RPL network and prevents duplicate transmissions of DIO messages. If an RPL network is in an inconsistent state, the interval of the trickle timer becomes shorter, and control messages are transmitted more frequently in order to stabilize the network. By contrast, if an RPL network is in a consistent state, the number of control message transmissions is reduced by increasing the trickle timer interval in order to reduce the overhead in the network incurred owing to control messages. If there is a node that moves frequently in an RPL network, a route that is suitable for movement must be selected for this node [4; 10]. For example, when the network is stable, the DIO messages spread slowly owing to the trickle timer. In this case, if a mobile node moves to another location, it may not be able to participate in the network owing to the slow spread of DIO messages. Indeed, this node may request a DIO message by transmitting a DIS message to a neighboring router node from the new location. However, such a mechanism diverges from the RPL standard. As such, the node must wait until a DIO message is received from the neighboring router nodes or the trickle timer must be reconfigured in an artificial manner. Therefore, appropriate scenarios must be established for mobility support in RPL [12]. Based on this, the trickle algorithm needs to be modified. There have been several studies to improve the trickle algorithm with the support of node mobility in RPL. [PERSON] et al. [6] proposed an enhanced version of the trickle algorithm, which tried to solve the problem of increased latency incurred from a listen-only period in the trickle algorithm.