In private local area networks (LANs), IP-based intranets have fundamentally changed the way companies conduct their business. Companies are moving their business applications to their intranets to extend over a wide area network (WAN). Companies are also embracing the needs of their customers, suppliers, and partners by using extranets (an intranet that encompasses multiple businesses). With extranets, companies reduce business process costs by facilitating supply-chain automation, electronic data interchange (EDI), and other forms of network commerce. Also Businesses of all types and sizes are facing the challenge of integrating data, voice and video traffic in easily managed, scalable, economical and flexible networks. Virtual Private Networks (VPNs) have emerged as a fundamental solution for meeting these challenges and business customers are now looking to service providers for value-added, cost-effective VPN services.