A recurring problem with communications networks is that as they grow and become more widely used, they become resistant to change. The Internet is now becoming subject to network ossification, making it difficult to deploy new capabilities to meet emerging needs. The advent of high performance network processors and advanced configurable logic devices now make it practical to virtualize the Internet, allowing multiple virtual networks to co-exist within the same physical infrastructure. This project is investigating the requirements for virtual networking architectures and the design options for realizing them.  The expected results of this work include analysis of major issues that affect the design of virtual network substrates. Options by which resources are allocated from the network substrate to virtual networks are being explored. The program is also investigating alternative approaches to virtualizing end-systems and design issues for virtual data links. In addition, the program is exploring architectures for virtualized routers. Virtualization places new requirements on network processors to enable different virtual routers to share resources in a single device, without interference. Network virtualization has the potential for eliminating the recurring problem of network ossification and enabling continuing innovation in core network technologies and services. It can have a dramatic impact on the nation's information technology infrastructure, allowing much more rapid introduction of new capabilities as new needs arise.