Traditional networking architectures have many limitations that need to be overcome to meet modern IT requirements. To overcome these limitations; Software Defined Networking (SDN) is taking place as the new networking approach. As traditional networking uses static switches, resource utilization is poor. There are packet loss and delay during switch breakdown. This paper proposes an implementation of a load balancing algorithm for an SDN based network to overcome the stated issues. To test the algorithm, a network is emulated using the Mininet and OpenDaylight platform (ODL) is used as an SDN controller. Python coding language is used to create fat-tree network topology and to write a load balancing algorithm. Finally, iPerf and Wireshark is used to test network performance. The network was tested before and after running the load balancing algorithm. The testing focused on some of the Quality of Service (QoS) parameters such as bandwidth and transfer rate in the fat-tree network. The algorithm increased bandwidth with at least more than 50\%, and improved network utilization