Network-Wide Decision Making: Toward A Wafer-Thin Control Plane

We argue for the refactoring of the IP control plane to provide direct expressibility and support for network-wide goals relating to all fundamental functionality: reachability, performance, reliability and security. This refactoring is motivated by trends in operational practice and in networking technology. We put forward a design that decomposes functionality into information dissemination and decision planes. The decision plane is formed by lifting out of the routers all decision making logic currently found there and merging it with the current management plane where network-level objectives are specified. What is left on each router is a wafer-thin control plane focused on information dissemination and response to explicit instructions for configuring packet forwarding mechanisms. We discuss the consequences, advantages and challenges associated with this design.