Control Delay and Load Based Controller Placement in LEO Satellite Network

The Software-Defined Network (SDN) architecture offers flexible management for Low Earth Orbit (LEO) satellite network, enhancing scalability and efficiency in the integrated satellite-terrestrial network. However, the dynamic topology induces constant changes in communication links between satellites, and the uneven distribution of ground traffic results in varying flow requests. Consequently, dynamic adjustments in controller placement become essential to accommodate these network changes. In this paper, a control delay and load based controller placement (DLCP) mechanism is proposed to address this issue. DLCP assesses the impact of flow requests on control delay, formulates the initial and dynamic controller placement problems (CPP) to reduce the control delay and flow setup time, and subsequently solves them using an improved heuristic algorithm. Simulation results demonstrate that the dynamic controller placement adjustment of DLCP yields superior performance in terms of average flow setup time and packet drop rate.