Service Function Chain Dynamic Scheduling in Space-Air-Ground Integrated Networks
Ziye Jia, Yilu Cao, Lijun He, Qihui Wu, Qiuming Zhu, Dusit Niyato, Zhu Han
TL;DR
This work tackles dynamic service function chain scheduling in space, air, and ground integrated networks by introducing a reconfigurable time extension graph (RTEG) to model time-varying multi-layer resources. It formulates SFC deployment as an ILP to maximize the number of successfully deployed chains under heterogeneous resources, then reformulates the problem as an MDP and solves it with a deep reinforcement learning framework (DRL-MSSNL-SAGIN) based on double DQN. Key contributions include the RTEG modeling, a detailed SFC deployment and scheduling model for SAGIN, and a DRL algorithm with a specialized VNF state transition mechanism, all validated by simulations showing improved convergence, scalability and resource utilization. The approach enables near real time dynamic orchestration of SFCs in highly mobile and heterogeneous SAGIN environments, with potential impact on global coverage and efficient NFV-based service provisioning.
Abstract
As an important component of the sixth generation communication technologies, the space-air-ground integrated network (SAGIN) attracts increasing attentions in recent years. However, due to the mobility and heterogeneity of the components such as satellites and unmanned aerial vehicles in multi-layer SAGIN, the challenges of inefficient resource allocation and management complexity are aggregated. To this end, the network function virtualization technology is introduced and can be implemented via service function chains (SFCs) deployment. However, urgent unexpected tasks may bring conflicts and resource competition during SFC deployment, and how to schedule the SFCs of multiple tasks in SAGIN is a key issue. In this paper, we address the dynamic and complexity of SAGIN by presenting a reconfigurable time extension graph and further propose the dynamic SFC scheduling model. Then, we formulate the SFC scheduling problem to maximize the number of successful deployed SFCs within limited resources and time horizons. Since the problem is in the form of integer linear programming and intractable to solve, we propose the algorithm by incorporating deep reinforcement learning. Finally, simulation results show that the proposed algorithm has better convergence and performance compared to other benchmark algorithms.
