One-Request Scheme for M2P Data Transmissions in Software-Defined IoT Networks

Software-defined networks (SDNs) have been utilized in applications of the Internet of Things (IoT), termed as software-defined IoT (SD-IoT) network, because of the popularity and capability of mobile devices being used for networking in relatively large areas. In an SD-IoT system, the sensing data are asynchronously harvested by the mobile sensing nodes and are also asynchronously uploaded to the gateways of an SDN. Thus, all the sensing data are asynchronously transmitted from the gateways to the data servers in the pattern of multipoints-to-point (M2P) data transmissions. Even if the sensing data are generated from the same sensing event, the controller of SDN has no knowledge about this relationship. Thus, such asynchronous M2P data transmissions from the same sensing event at the gateways will generate many redundant requests to their controller by OpenFlow protocol of SDN. In this paper, we investigate the redundant requests caused by the asynchronous M2P data transmissions in the SD-IoT network. We model the relationship between the sensing events and the uploading gateways by utilizing their spatial locations and the distribution of mobile sensor nodes. To reduce the loads on the controller for the asynchronous M2P data transmissions, we propose a one-request scheme for SD-IoT networks, to batch the forwarding rules of the multiple data transmissions from the same event by the first one request from a gateway. Furthermore, we discuss the conflict between the M2P data transmission and the potential sensing events and propose the routing scheme with multiple sensing events. Our extensional simulations verify the effectiveness of our proposed approach.