The Ports tab displays a list of the current port service mappings, and lets you enable or disable UPnP port forwarding. To enable or disable UPnP port forwarding: Set UPnP port forwarding to ON to allow UPnP devices on your Fiber network to set their own port forwarding rules.
VRML (Virtual Reality Modeling Language) is a language for describing three-dimensional (3-D) image sequences and possible user interactions to go with them.
Variable refrigerant flow. Variable refrigerant flow (VRF), also known as variable refrigerant volume (VRV), is an HVAC technology invented in Japan by Daikin company in 1982. Like ductless minisplits VRFs use refrigerant as the cooling and heating medium.