The world is moving towards the ubiquitous deployment of the Internet. Virtual private networking technology provides the medium to use the public Internet backbone as an appropriate channel for private data communication. By replacing expensive private network bandwidth with relatively low-cost bandwidth, much of the remote communications burden is transferred over to ISPs. A multilayer technology, multiprotocol label switching (MPLS), offers an alternative tunneling mechanism for implementing IP VPNs. MPLS combines the performance of layer 2 switching with layer 3 routing to provide a scalable and flexible architecture for building VPNs. MPLS represents the next level of standards-based evolution in combining layer 2 (data link layer) switching technologies with layer 3 (network layer) routing technologies. The primary objective of this standardization process is to create a flexible networking fabric that provides increased performance and scalability. This includes traffic-engineering capabilities, which provide, for example, aspects of quality of service (QoS), and facilitate the use of virtual private networks. This paper covers the general idea of MPLS in VPNs; it also covers a quantitative analysis of MPLS in VPNs.