The rapid growth of the Internet and the widespread deployment of networks built around the Internet Protocol suite are creating a demand for new capabilities in IP networks. The IP-based virtual private network (VPN) technology is rapidly becoming the foundation for the delivery of future Internet services, and many service providers are offering value-added applications on top of their VPN transport networks. Two unique and complementary architectures based on traditional industry standard encrypted tunnels (IPSec) and still developing Multiprotocol Label Switching (MPLS) technologies are emerging to form the predominant framework for delivery of high performance VPN services. We analyzed the strengths and the weaknesses of both the approaches, and compared their performance and scalability features by carefully testing them against the requirements of the future optical high performance backbones. Our technical considerations and experimental results strongly emphasized the better scalability and reliability of the MPLS/BGP model that seems to be the most promising approach for the provisioning of VPN services on the future Giga-speed optical backbones.