  Software Defined Networking (SDN) is a promising approach for improving the
performance and manageability of future network architectures. However, little
work has gone into using SDN to improve the performance and manageability of
existing networks without requiring a major overhaul of the existing network
infrastructure.
  In this paper, we show how we can dramatically improve, or supercharge, the
performance of existing IP routers by combining them with SDN-enabled equipment
in a novel way. More particularly, our supercharged solution substantially
reduces the convergence time of an IP router upon link or node failure without
inducing any reconfiguration of the IP router itself. Our key insight is to use
the SDN controller to precompute backup forwarding entries and immediately
activate them upon failure, enabling almost immediate data-plane recovery,
while letting the router converge at its typical slow pace. By boosting
existing equipment's performance, we not only increase their lifetime but also
provide new incentives for network operators to kickstart SDN deployment.
  We implemented a fully functional "supercharger" and use it to boost the
convergence performance of a Cisco Nexus 7k router. Using a FPGA-based traffic
generator, we show that our supercharged router systematically converges within
~150ms, a 900x reduction with respect to its normal convergence time under
similar conditions.
