In this demo, we present Ripcord, a modular platform for rapidly prototyping scale-out data center networks. Ripcord enables researchers to build and evaluate new network features and topologies, using only commercially available hardware and open-source software. The Ripcord demo will show three examples of custom network functions, operating together, on top of a 160-node cluster. The first is a routing engine that isolates classes of traffic. The second is a dynamic network manager than adjusts links and switch power states to reduce energy. The third is a statistics aggregator that supports network health monitoring and automatic alerts. The demo will be interactive, with a visualization of live parameters for each link and switch, such as bandwidth, drops, and power status, as well a control panel to modify the traffic load. We feel that an interactive demo is the best way to introduce the research community to Ripcord and get their feedback. Categories and Subject Descriptors: C...