Intelligent design enables architectural evolution

What does it take for an Internet architecture to be evolvable? Despite our ongoing frustration with today's rigid IP-based architecture and the research community's extensive research on clean-slate designs, it remains unclear how to best design for architectural evolvability. We argue here that evolvability is far from mysterious. In fact, we claim that only a few "intelligent" design changes are needed to support evolvability. While these changes are definitely nonincremental (i.e., cannot be deployed in an incremental fashion starting with today's architecture), they follow directly from the well-known engineering principles of indirection, modularity, and extensibility.