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The Open Network Laboratory (ONL) is a remotely accessible gigabit network testbed designed to enable network researchers to conduct experiments using high performance routers and applications. ONL's Remote Laboratory Interface (RLI) allows users to easily configure a network topology, initialize and modify the routers' routing tables, packet classification tables and queuing parameters. It also enables users to add software plugins to the embedded processors available at each of the routers' ports, enabling the introduction of new functionality. The routers provide a large number of built-in counters to track various aspects of system usage, and the RLI software makes these available through easy-to-use real-time charts. This allows researchers to expose what is happening under the surface enabling them to develop the insights needed to understand system behavior in complex situations and to deliver compelling demonstrations of their ideas in a realistic operating environment. This tutorial is structured to provide both a quick overview of ONL as well as detailed instructions on the use of its features. Each section covers a group of RLI features (e.g., basics, filters and queues, router plugins) and begins with a quick tour of the features, emphasizing how the ONL can be used to carry out associated networking experiments. This introduction is followed by detailed instructions on and examples of the RLI features. Each section ends with implementation details that describe what is required under the hood to support the various features.
Why Did We Build ONL?
As the Internet has matured and become more complex, it has become increasingly difficult for networking researchers to conduct research that requires experimental modifications to the data path of high performance routers. The closed architectures of commercial routers makes them largely inaccessible for this type of research and in any case, the time and effort required to make experimental modifications to these systems, makes this type of work prohibitively difficult for most researchers. This is unfortunate, since many of the more exciting opportunities for advanced network services require the introduction of new functionality in the router data path.
As an alternative, networking researchers have used testbeds constructed from PC-based routers running standard operating systems. While these testbeds offer the researcher great access to the testbed infrastructure and potentially a high-degree of control, the architectures are quite different from those of modern routers which are distributed in nature and operate under real-time constraints.
The Open Network Laboratory (ONL) has been designed as a resource for the networking research community, to enable researchers to conduct experimental research using high performance routers and applications. ONL dramatically reduces the barrier-to-entry for this kind of research by providing access to a remote testbed of open, high performance routers and hosts that can be controlled through an intuitive Remote Laboratory Interface (RLI).
ONL builds on an earlier effort at Washington University, in which Gigabit Network Kits were produced for use by research groups at over thirty other universities. Each kit consisted of an open high performance switch, network interface cards and associated software. While the kits program was moderately successful, it became clear that most groups found it difficult to maintain the level of expertise needed to manage the experimental equipment and use it effectively. They found themselves spending far too much time on mundane system administration and too little time using the equipment for network experiments. The more recent, and highly successful development of Emulab, provided an alternate model for how to enable experimental network research. In developing our ideas for the Open Network Lab, we have directly borrowed the Emulab approach, although we have substituted high performance routers with packet forwarding in hardware, for Emulab's PC-based routers. This enables researchers to work directly with systems that are architecturally similar to commercial routers. The routers' packet forwarding and queueing mechanisms are implemented using configurable logic that can be dynamically reconfigured and each port has an embedded processor that hosts software plugins that can be added to provide new capabilities.
What Can You Do With ONL?
The RLI allows a remote user to easily configure experiments and monitor components (e.g., traffic, queues). Users can evaluate new and existing protocols and applications in a realistic testbed. They can add new features to routers by loading software into the embedded processors or loading hardware modules into the FPGA packet processing engines. The extensive support for real-time data visualization allows users to develop the insights needed to understand the behavior of new capabilities and allows researchers to deliver compelling demonstrations of their research ideas in a realistic operating environment.
| Tutorial >> Overview |
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