DumbNet: A Smart Data Center Network Fabric with Dumb Switches

Today's data center networks have already pushed many functions to hosts. A fundamental question is how to divide functions between network and software. We present DumbNet, a new data center network architecture with no state in switches. DumbNet switches have no forwarding tables, no state, and thus require no configurations. Almost all control plane functions are pushed to hosts: they determine the entire path of a packet and then write the path as tags in the packet header. Switches only need to examine the tags to forward packets and monitor the port state. We design a set of host-based mechanisms to make the new architecture viable, from network bootstrapping and topology maintenance to network routing and failure handling. We build a prototype with 7 switches and 27 servers, as well as an FPGA-based switch. Extensive evaluations show that DumbNet achieves performance comparable to traditional networks, supports application-specific extensions like flowlet-based traffic engineering, and stays extremely simple and easy-to-manage.