Dynamic Processing while Transmitting for SDN-based Space-Terrestrial Integrated Networks

The space-Terrestrial information network integrates the characteristics of satellite networks and terrestrial networks and can support diversified space network requirements, which has also become a new trend in future network development. In the process of coordinated transmitting between space and terrestrial, satellite may generate a data flow with a set of tasks to be processed while transmitting. Because of the dynamic changes in the links between nodes in the satellite network, how to effectively place the tasks will be huge challenges. In this paper, we considere the traffic changes brought about by task processing, the effectiveness of links, and combined with the operation laws of satellite network and have studied the placement of tasks in dynamic transmitting and processing scenarios. First, we formulate the Task Placement In Dynamic Transmitting-Processing (TPDTP) problem, and then divide the problem into three parts: flow path selection, task allocation between planes, and task placement within plane. For flow path selection, we proposed the Waiting-Time Reducing Path Select (WTRPS) algorithm. For the task allocation problem between planes, we proposed the Time-Constrained Task Placement (TCTP) algorithm and Waiting-Time Utilization Task Placement(WTUTP) algorithm. Finally, we propose Intra-plane Task Placement (IPTP) algorithm to solve the problem of task placement within plane which comprehensive consider the changes in traffic rate and the processing performance of nodes. We evaluate the proposed algorithms using simulations and present evaluation results to show the effectiveness of our design.