Donghao Zhao Wei Shi Yu Lu Xi Li Yicen Liu On-Policy Versus Off-Policy Reinforcement Learning for Multi-Domain SFC Embedding in SDN/NFV-Enabled Networks. 123049-123070 2024 12 IEEE Access https://doi.org/10.1109/ACCESS.2024.3430865 db/journals/access/access12.html#ZhaoSLLL24 streams/journals/access