Colosseum Tutorial at ACM MobiCom 2021

New Orleans

Monday, October 25, 2021

Organizers: Stefano Basagni, Kaushik R. Chowdhury, Tommaso Melodia

Large-scale experimentation is a core component of wireless research. However, experimental capabilities are as effective and useful as their ability of capturing diverse wireless environments and conditions realistically, in a controlled environment that is highly accessible, programmable and where experiments can be repeated for fair and informative comparison among solutions. Up until now, the research community lacked widespread access to testbeds offering such critical capabilities, especially at scale.

The past few years have seen the emergence of larger facilities with the characteristics required for repeatable wireless experimentation at scale. Examples include the testbeds of the NSF Platform for Advanced Wireless Research (PAWR) program and Colosseum, which, with its capability of emulating over 60k wireless channels, is hailed as the world's largest wireless network emulator.

Colosseum is a massive RF and computational facility enabling large-scale experiments through a pool of 128 Software-defined Radios (SDRs) controlled by dedicated and remotely-accessible host computers called Standard Radio Nodes (SRNs). It emulates wireless signals traversing space and reflecting off multiple objects and obstacles as they travel from transmitters to receivers, through its Massive Channel Emulator (MCHEM) that consists of an additional array of 128~SDRs and 64 FPGAs. As such, Colosseum can create virtual worlds, as if the radios are operating in an open field, downtown area, shopping mall, or a desert, by generating more than 52 terabytes of data per second.

Colosseum is hosted at Northeastern University, and is freely accessible by anybody in the research community with an active grant on wireless research. We believe that a tutorial on Colosseum is timely and relevant to the MobiCom community as it will offer to the attendees a clear introduction on how to access the emulator, and how to run repeatable wireless experiments at scale on it, emphasizing its capabilities of modeling a vast variety of scenarios, channel conditions, and traffic and mobility patterns. Particularly, we will show how to use Colosseum in a set of scenario relevant to most wireless research: Local area networking (e.g., WiFi-based networks), cellular networks, and wireless ad hoc scenarios (e.g., aerial or vehicular networking). Out tutorial will further explain how wireless emulated experiments can be ported to other real-world wireless testbeds, including the PAWR platforms, thus facilitating full-cycle experimental wireless research: Design, experiments and tests at scale in a fully controlled and observable environment, and testing in the field.

    
Knowledge that the Audience will Gather with the Tutorial

By the end of the tutorial the attendees will know the about wireless emulation, how Colosseum does it, and how to access and how to use the emulator. We will explain the fundamentals of wireless network emulation, its use for experimental wireless research, and how Colosseum does it at scale and with hardware-in-the-loop. We will describe the Colosseum architecture and its unique emulation system, called MCHEM. We will talk about Radio Frequency (RF) and traffic scenarios in Colosseum, how they are designed, and how they capture realistic wireless environments and conditions.

After the initial overview of Colosseum, attendees will be guided to the usage of the emulator: How to access it and on how to run experiments. Particularly, we will explain the Colosseum containerized system and will detail how to instantiate containers on Colosseum, how to work with them, and how to save them for a later use. We will then show how to run actual experiments in Colosseum and how to use its channel emulation system. Practical demonstrations will be given of Colosseum use cases, including WiFi and cellular networking and multi-hop ad hoc networks. These experiments will run on customized containers for WiFi and LTE applications that are prepared by the organizers' team at Northeastern University and are accessible to the Colosseum users.

Finally, the attendees will learn how to transfer Colosseum-based experiments onto testbeds for experiments in the field. In particular, we will cover how a Colosseum experiments can be ported to one of the PAWR platforms.

    
Format

The Colosseum tutorial is scheduled as a half-day tutorial (4 hours), organized into two sessions.

The first session will be made up of three presentations followed by a Q&A. It will include an introduction to wireless network emulation and how it is done in Colosseum, an overview of the Colosseum architecture, and how realistic scenarios can be created for network experiments on Colosseum.

The second session will be a live, more interactive practical demonstration of how researchers can utilize Colosseum to run wireless emulation experiments on multiple diverse scenarios (e.g., WiFi, cellular and ad hoc). We also plan on a final Q&A at the end of the tutorial to address any questions and provide guidelines and support for the researchers who are interested to access and use Colosseum for their research.

    
Tentative Schedule
Time Topic Presenter
1.30pm - 3pm Session 1
1.30pm Part 1: Wireless network emulation and Colosseum Tommaso Melodia
1.55pm Part 2: Colosseum architecture and emulation system Kaushik R. Chowdhury
2.20pm Part 3: Colosseum scenarios and use-cases Stefano Basagni
2.45pm Part 4: Q&A All
3pm - 3.30pm Break
3.30pm - 5.30pm Session 2
3.30pm Part 1: How to use Colosseum for first-time users TBD
3.55pm Part 2: Demo: WiFi, cellular and ad hoc scenarios TBD
4.45pm Part 3: From Colosseum to PAWR Manu Gosain
5.10pm Part 4: Q&A and final remarks All
    
Requirements for the Attendees

  • Demos will be given from a Linux-based system, which is the operating system of most Colosseum components. Familiarity with basic Linux commands and its command line interface (e.g., ssh, scp/rsync) is recommended. Basic knowledge of computer networking and wireless concepts is also useful.
  • If attendees are interested in using Colosseum and want to try to replicate what is shown during the tutorial they would need a computer/laptop with Internet access and should have already registered to use Colosseum.