IPv6 over low-power wireless personal area network (6LoWPAN) has been widely used for large-scale sensing and actuating purposes in the Internet of Things (IoT). Though promising, many challenges, such as high latency, heterogeneity, and packet loss persist. To mitigate these challenges, the software-defined network (SDN) technique can be hybridized with existing IoT structures that can address many of them. In this article, we propose an approach-edge-based 6LoWPAN-SDN (6LE-SDN) architecture, which can improve the system limitations mentioned. It uses an edge-based computational capability to improve the network performance over 6LoWPAN. To reduce heterogeneity, we develop a hybrid-edge switch that helps to enable communication among 6LoWPAN and SDN entities. For efficient communication between different devices, a new protocol-edge-based 6LoWPAN-SDN protocol (6LE-SDNP) is proposed, which is capable of ensuring optimal routing of the packet for efficient communication among the devices. We use the SDN-based edge controller for reducing the latency of the network apart from improving the interoperability feature. The testbed evaluation of the proposed solution indicates satisfactory performance in terms of reducing latency by 60% and network overhead by 91%. The 6LE-SDN network also succeeded in reducing the average round trip time (RTT) by 31% and the packet loss by 70% as compared to that of the traditional 6LoWPAN-based IoT.