End-to-end QoS architecture for VPNs: MPLS VPN deployment in a backbone network

Virtual private networks (VPNs) enable companies to connect geographically dispersed offices and remote workers via secure links to the private company network, using the public Internet as a backbone. Specially, VPN service in the broadband data communication network is very important and necessary to take in users who want to specify group communication. VPN mechanisms are needed which work over existing deployed backbones, and which can also be migrated to new backbones like MPLS (Multi-Protocol Label Switching). MPLS is the latest step in the evolution of multi-layer switching in the Internet. In this paper, we clarify how MPLS can be applied to creating VPNs. For this, we researched an architectural model for building VPNs in an MPLS domain. The proposed model takes advantage of both network layer peering and packet switching, and link-layer circuit and per-stream switching. It comes with a design scheme and an implementation procedure for VPN services in MPLS systems. Then we describe MPLS-based VPN service procedures and we describe MPLS VPN schemes that must be accommodated with existing network backbones and must also provide for a full range of QoS characteristics