In multiprotocol label switching (MPLS) or a router-based network, a routing table instance associated with a virtual private network (VPN) or frame relay access port.There may be multiple VRFs (one per VPN) in a single router serving multiple VPNs, a common situation within carriers and Internet service providers (ISPs). In a complex multi-site enterprise, there may be several routers, perhaps one serving the headquarters site and one or more serving the remote sites, and multiple VRFs, with each VRF serving one VPN. See also carrier, frame relay, ISP, MPLS, router, and VPN.