Overview on MPLS Virtual Private Networks

The basic idea, features, and necessity of multiprotocol label switching (MPLS) are given in this paper, with a special focus on virtual private networks (VPN) as one of the most important features that MPLS as technology enables and supports. In this context, we first describe the general VPN models, the overlay and the peer model, and than analyze different models, such as the BGP/MPLS virtual private networks and the layer-2 MPLS virtual private networks. All over the paper, the benefits provided by using MPLS for different VPN models are emphasized, with particular attention to improved scalability, management, and quality of service (QoS).