Rethinking packet forwarding hardware
Martin Casado1, Teemu Koponen2, Daekyeong Moon and Scott Shenker
As network speeds have increased, there has been an increasing reliance of hardware for accelerating packet forwarding. Network equipment makers have followed two basic approaches: either embedding specific algorithms in hardware or using programmable network processors. The former approach has dominated in recent years, having achieved very attractive price/performance ratios, but it provides very limited flexibility. In this project, we propose a different approach to hardware packet forwarding, in which the hardware does not attempt to implement the logic of forwarding but instead merely mimics the results of previous software-driven forwarding decisions. This provides complete forwarding flexibility, while achieving significant speedup. The resulting forwarding speeds do not depend on the complexity of the forwarding decision, but on the cache hit rate on matching previous forwarding decisions.
2 Helsinki Institute for Information Technology