Virtual Routing and Forwarding

Virtual routing and forwarding (VRF) is a technology included in IP
(Internet Protocol) network routers that allows multiple instances of a
routing table to exist in a router and work simultaneously. This
increases functionality by allowing network paths to be segmented
without using multiple devices. Because traffic is automatically
segregated, VRF also increases network security and can eliminate the
need for encryption and authentication. Internet service providers
(ISPs) often take advantage of VRF to create separate virtual private
networks (VPNs) for customers; thus the technology is also referred to
as VPN routing and forwarding.

VRF acts like a logical router, but while a logical router may include
many routing tables, a VRF instance uses only a single routing table.
In addition, VRF requires a forwarding table that designates the next
hop for each data packet, a list of devices that may be called upon to
forward the packet, and a set of rules and routing protocols that
govern how the packet is forwarded. These tables prevent traffic from
being forwarded outside a specific VRF path and also keep out traffic
that should remain outside the VRF path.