NFV,网络功能虚拟，虚拟防火墙的详细说明，利用mininet开启防火墙，在一定条件下用软件实现硬件防火墙的部分功能(NFV, the virtual function of the network, the detailed descr iption of the virtual firewall, the use of mininet to open the firewall, and some functions of the hardware firewall under certain