Virtualization in both computer systems and network elements is becoming increasingly part of the Internet. Apart from posing new challenges, virtualization enables new functionalities, and hints at a future Internet architecture, which contains a physical, but polymorphic, substrate on which various parallel infrastructures can be created on demand. This article explores such a new “architecture of virtual infrastructures”. The FEDERICA project and the recent evolution trends in the National Research and Education networks are taken as examples of this new type of network infrastructure, which is an evolution of the classic network.