Fig. 3 shows the handover delay by retransmission counts. Although the handover delay due to the retransmission can be increased, the CoMP can guarantee the reliability of handover message by using CoAP retransmission mechanism. On the contrary, the related standard mobility protocols such as MIPv6 do not support the retransmission mechanism. As result, CoMP can be utilized to the high reliability service such as remote healthcare service on IoT environment.