An Overview of Virtual Private Network (VPN): IP VPN and Optical VPN

摘要

Recently, there has been rapid development and deployment of virtual private network (VPN) services. There are wide varieties of IP-based VPNs and optical VPNs (OVPNs) proposed in the literature and readers could easily get confused with so many different types of VPNs. The purpose of this paper is to present a comprehensive overview of the VPN and discuss the main issues associated with the design of IP VPN and OVPN. We first present a classification of the VPNs including CE-based, network based, customers provisioned, provider provisioned, connection oriented, connectionless oriented, port based, connection based, layer 1 VPN, layer 2 VPN, and layer 3 VPN, and describe different VPN protocols such as IPSec, GRE and MPLS. We then review the recent work on OVPN by different standard bodies, and outline the key requirements for OVPN service providers and customers. Finally, we describe several OVPN architectures appeared in the literature, highlight the future work in OVPN.