The Common Open Research Emulator (CORE) is a tool for emulating networks on one or more machines. You can connect these emulated networks to live networks. CORE consists of a GUI for drawing topologies of lightweight virtual machines, and Python modules for scripting network emulation.
VisualVNC is a connector between virtual network and physical network.
VisualVNC is a connector between virtual network and physical network. A virtual network mainly refers to the topology created by GNS3 (Graphical Network
Simulator, a popular network simulator), the physical network means the real machines or virtual machines (created by VMware, virtualbox and so on) which are running Windows.