Network-layer innovation has proven surprisingly difficult, for various reasons: existing protocols ignore competing economic interests; also, a few protocols dominate, enabling layer violations that lead to further entrenchment of technologies. Many shortcomings of today's internetwork layer result from its inflexibility with respect to the policies of the stakeholders, namely users and service providers. The consequences of these failings are well-known: various hacks, layering violations, and overloadings are introduced to enforce policies and attempt to get the upper hand in various "tussles". The result is a network that is increasingly brittle, hostile to innovation, vulnerable to attack, and insensitive to concerns about accountability and privacy. The goal of the Postmodern Internetwork Architecture project is to design, implement, and, through daily use, evaluate a minimalist internetwork layer and accompanying auxiliary functionality that anticipates tussles and allows them to be played out in policy space, as opposed to in the packet-forwarding path. The overarching goal of the project is to make a larger portion of the network design space accessible without sacrificing the economy of scale offered by the unified Internet.
