VRF

VRF is an acronym used in several technical fields, referring to distinct technologies in HVAC, cryptography, and computer networking. The most common meanings are Variable Refrigerant Flow in heating, ventilation, and air conditioning (HVAC) systems; Verifiable Random Function in cryptography; and Virtual Routing and Forwarding in networking. Each use reflects different principles and applications.

Variable refrigerant flow systems use a single outdoor unit connected to multiple indoor units. The refrigerant flow is modulated by inverter-driven compressors and electronic expansion devices to match demand in each zone. This enables zoning, energy efficiency, and flexible installation, especially in commercial buildings. VRF can support simultaneous heating and cooling with heat-recovery variants.

A verifiable random function is a cryptographic primitive that, with a secret key and an input, yields a pseudo-random output and a proof that the output is correct. The proof can be verified by anyone with the public key, without revealing the secret key. VRFs provide unpredictability and verifiability and are used in leader election, randomness beacons, lottery-style selections, and to derive fair randomness in blockchain protocols.

Virtual routing and forwarding enables multiple independent routing tables within a single router or switch. Each VRF isolates routes and forwarding decisions, allowing overlapping IP addresses across tenants or services. VRFs are central to MPLS VPN deployments and to large enterprise networks; VRF-Lite variants exist for non-MPLS contexts. Route distinguishers and route targets manage inter-VRF routing.