The Missing Link: Putting the Network in Networked Cloud Computing

The backbone of IT infrastructure is evolving towards a service-oriented model, in which distributed resources, ei- ther software or hardware, can be composed as a customized IT service on demand. In particular, cloud computing infrastructure services manage a shared "cloud" of servers as a unified hosting substrate for diverse applications, using various technologies to virtualize servers and orche strate their operation. Emerging cloud infrastructure-as - a-service efforts include Eucalyptus, Nimbus, Tashi, OpenCirrus, and IBM's Blue Cloud. Extending cloud hosting into the network is a crucial step to enable on-demand allocation of complete net- worked IT environments. This paper reports on our effort to advance cloud resource control to cloud networks with multiple substrate providers, including network tran sit providers. Our vision is to enable cloud applica- tions to request virtual servers at multiple points in the ne twork, together with bandwidth-provisioned network pipes and other network resources to interconnect them. This capability is a significant advance beyond the cloud infrastructure-as-a-service models that are generating s o much excitement today. This paper reports on a RENCI-Duke collaboration (http://www.geni-orca.renci.org ) to build a cloud network testbed for the Global Environment for Network Innovation (GENI) Initiative recently launched by the National Science Foundation and BBN. GENI (http://www.geni.net) is an ambitious futuristic vision of cloud networks as a platform for research in network science and engineering. A key goal of GENI is to enable researchers to exper- iment with radically different forms of networking by running experimental systems within private isolated slices of a shared testbed substrate. A GENI slice gives its owner control over some combination of virtualized substrate resources assigned to the slice, which may include virtual servers, storage, programmable network elements, net- worked sensors, mobile/wireless platforms, and other programmable infrastructure components attached to the cloud network. GENI slices are built-to-order for the needs of each experiment. We focus on progress in building a unified control framework f or a prototype GENI facility incorporating RENCI's optical network stacks on the Breakable Experiment al Network (BEN). BEN is a testbed for open experimentation on dedicated optical fiber that spans the Re search Triangle area, and links server clusters on each campus. We have demonstrated a key milestone: on-demand creation of complete end-to-end slices with private IP networks linking virtual machines allocated at multiple si tes (RENCI, Duke, and UNC). The private IP networks are configured within stitched layer-2 VLANs instantiated f rom the BEN metro-scale optical network and the National Lambda Rail (NLR) FrameNet service. In the context of GENI, this capability enables a researcher to conduct safe, reproducible experiments with arbitrarily modified network protocol stacks on a private isolated network that meets defined specifications for the experiment .