This paper documents a real-world field study that concludes that the availability and call quality of VoIP over Multi-protocol Label Switching (MPLS) is comparable to that of VoIP over the public Internet. Avaya measured the ability of MPLS services to support business quality VoIP communications. Avaya found, among other surprising fact, that the performance and availability of both the MPLS Best Effort and MPLS Premium services are not better than that of default Internet connections.