Chapter 7 - Virtual Private Networks and MPLS

Abstract

This chapter presents an overview of Virtual Private Networks (VPNs) and explores Multiprotocol Label Switching (MPLS) VPN concepts. The chapter also discusses MPLS L2-L3 VPNs and their configurations and broadens one's working knowledge by providing a practical case study and a VPN cost justification case study. A VPN is a network with the characteristics of a private network that offers protection from data modification, data interception or disclosure, and denial of service while operating on a public network. The Internet Protocol Security (IPSec) protocol was developed as a security standard for Internet traffic. It can operate in two modes: tunnel and transport. In the tunnel mode, data encryption is not provided; however, in the transport mode data encryption is provided. MPLS is a tunneling and switching technology. The switched tunnels that MPLS offers provide for multiplexing or aggregation, Quality of Service (QoS) assignment, and traffic engineering. MPLS tunnels can be used standalone or in conjunction with the VPN tunnel protocols. There has been wide acceptance of MPLS with Generic Routing Encapsulation (GRE) tunnels. To build a secure VPN, firms with strict security requirements need to acquire special software and hardware that builds secure paths or tunnels from end-to-end. The software and hardware should allow for end-to-end data encryption; however, end-to-end encryption and security bring their own challenges and management issues.