UC San Diego

In this thesis, we look at changes in the end-host network stack that are needed to support REACToR, a hybrid data- center network. We discuss the requirements posed by REACToR and propose a host-traffic control protocol. We then describe three different implementations of the protocol. To schedule optical circuits on a microsecond scale, a hybrid top-of-rack switch needs to control end- host traffic. The most important performance characteristic of the host-control protocol is its responsiveness, namely how quickly can a flow be paused or unpaused. The first implementation of the host-control protocol is based on priority-based Ethernet flow control. While it provides good performance by taking advantage of hardware implementations in commodity network cards, the implementation has correctness issues. The second implementation is the Software-defined Data Plane proposal which uses DPDK to provide a flexible user-land network stack. The host-control protocol can be a subset of the Software-defined Data Plane. However since the stack is implemented in software, there are performance penalties. It also requires the original network stack to be replaced, which might entail a lot of changes in end hosts. The third implementation is a reprogrammed network card built with a Netronome network flow processor. Being a hardware implementation, it has better performance and does not demand changes in the operating system. Thus it can help REACToR achieve the goal of operating "under the radar"