The Internet’s basic design has remained largely unchanged since it first became commercial in the 1990s. Now that the Internet is the centerpiece of our global communications infrastructure, it is essentially impossible to alter its design in any significant way. Unfortunately, such changes are needed to improve the Internet’s performance and security. This project aims to resolve this paradox with a design called the Extensible Internet. This is a collaborative project which brings together investigators from Mount Holyoke College, New York University, the University of Washington, and International Computer Science Institute at the University of California at Berkeley.<br/><br/>In today’s Internet, layer 3 has two basic functions: (i) connect all layer 2 networks and (ii) provide the packet delivery services on which host applications are built. The key aspect of the Extensible Internet is that it splits layer 3 into two layers. The first, which remains layer 3 and can use the current Internet Protocol (IP), handles the first function of connecting layer 2 networks. The second requires a new layer (called layer 3.5) that supports an extensible set of packet delivery services, and thus handles the second function of providing the services on which host applications are built. In this way, the Extensible Internet design leaves the current Internet unchanged but is able to provide an extensible set of new packet delivery services that will improve the Internet’s performance and security.<br/><br/>The Extensible Internet design is incrementally deployable (i.e., no unchanged applications or domains would lose connectivity), compatible with economic incentives, and can continue to evolve as new requirements arise. As such, it provides a practical way for the Internet to evolve far beyond its current design. If the Extensible Internet design is adopted, it would have a significant impact on the nature of the Internet. In particular, transitioning to the Extensible Internet is not just a one-time change in functionality, but transforms the Internet from a single and unchanging service model (best-effort packet delivery) to an evolving and expanding set of network-provided services. In addition, in pursuing this agenda, the investigators will work to increase the diversity of the STEM workforce through ongoing efforts in their own research groups and the outreach programs in their respective departments. The investigators will also incorporate their results into their courses and make the material freely available.<br/><br/>All of the code from this project will be available on the project’s website at ExtensibleInternet.org.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.