CoAP-Based Mobility Management for the Internet of Things.

Most of the current mobility management protocols such as Mobile IP and its variants standardized by the IETF may not be suitable to support mobility management for Web-based applications in an Internet of Things (IoT) environment. This is because the sensor nodes have limited power capacity, usually operating in sleep/wakeup mode in a constrained wireless network. In addition, sometimes the sensor nodes may act as the server using the CoAP protocol in an IoT environment. This makes it difficult for Web clients to properly retrieve the sensing data from the mobile sensor nodes in an IoT environment. In this article, we propose a mobility management protocol, named CoMP, which can effectively retrieve the sensing data of sensor nodes while they are moving. The salient feature of CoMP is that it makes use of the IETF CoAP protocol for mobility management, instead of using Mobile IP. Thus CoMP can eliminates the additional signaling overhead of Mobile IP, provides reliable mobility management, and prevents the packet loss. CoMP employs a separate location management server to keep track of the location of the mobile sensor nodes. In order to prevent the loss of important sensing data during movement, a holding mode of operation has been introduced. All the signaling procedures including discovery, registration, binding and holding have been designed by extending the IETF CoAP protocol. The numerical analysis and simulation have been done for performance evaluation in terms of the handover latency and packet loss. The results show that the proposed CoMP is superior to previous mobility management protocols, i.e., Mobile IPv4/v6 (MIPv4/v6), Hierarchical Mobile IPv4/v6 (HMIPv4/v6), in terms of the handover latency and packet loss.