Revisit the Strings Versus Clouds Debate for the Internet Architecture Part II: Control, Management and TCP

The clouds (IP) versus strings (connection-oriented) debate over the Internet architecture is reexamined. Controllability and observability are shown to be the key to the performance (QoS) of the networks. The clouds architecture treats the network as a black box, making it uncontrollable and unobservable; in contrast, the strings architecture was designed to be a controllable and observable structure. With the simple-core-complex-edge model, the clouds architecture seems to simplify network management. However, the rise of policy-based networking argues for centralized management. Finally, TCP is shown to be unscalable in performance due to its half-blind observability and half-effort controllability.