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March 23, 2016

The CEAL of Fog

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By Dr. Mung Chiang
OpenFog Consortium Board Member
Arthur LeGrand Doty Professor of Electrical Engineering, Princeton University

Fog networking is an architecture that uses one or a collaborative multitude of end-user clients or near-user edge devices to carry out a substantial amount of storage, communication and management. “Architecture” allocates functionalities. “Engineering artifacts” that may use fog architectures include 5G, cyber physical systems, edge big data, and the Internet of Things.

Fog is not a binary choice between cloud and edge. It is a mutually beneficial, inter-dependent Cloud-to-Things Continuum (CTC). It is a continuum: To the wearable device, a mobile phone may be viewed as the cloud. They are inter-dependent; for example, coordination among devices on the edge may rely on the cloud. They are also mutually beneficial: certain functions are naturally more advantageous to carry out on the network edge while others are better suited for cloud. The interface between edge and cloud and the placement of functionalities along the CTC is indeed a key aspect of fog research and development.

Why would we be interested in the fog view now? I think of the four main reasons coded as CEAL:

  1. Cognition: Awareness of Client-centric objectives. Following the end-to-end principle, some of the applications can be best enabled by knowing the requirements on the clients. This is especially true when privacy and reliability cannot be trusted in cloud, or when security is enhanced by shortening the extent over which communication is carried out.
  1. Efficiency: Pooling of local resources. There are typically hundreds of gigabytes sitting idle on tablets, laptops and set-top boxes in a household every evening, or across a table in a conference room, or among the passengers of a public transit system. Similarly, idle processing power, sensing ability and wireless connectivity within the edge, may be pooled within a fog network.
  1. Agility: Rapid innovation and affordable scaling. It is usually much faster and cheaper to experiment with client and edge devices. Rather than waiting for vendors of large boxes inside the network to adopt an innovation, in the fog world a smaller team may take advantages of smart phone API and SDK, proliferation of mobile apps, and offer a networking service through its own API.
  1. Latency: Real time processing and cyber-physical system control. Edge data analytics, as well as the actuations it enables through control loops, often have stringent time requirement and can only be carried out on the edge, “here and now.” This is particularly essential for Tactile Internet: the goal of millisecond reaction time on networks that enable virtual-reality-type interfaces between humans and devices.

Fog is starting to shape the future of the balance of power and distribution of innovation across the entire industry food chain. There is also no shortage of challenges on both the R&D front and the business front. To address the R&D challenges, we need inter-disciplinary research across networking, computing, device hardware/OS, pricing, HCI and data science. We will also benefit from industry-academia interactions, as exemplified in the OpenFog Consortium, where the collaboration and the work is just getting started.

About the author: Dr. Mung Chiang is the Arthur LeGrand Doty Professor of Electrical Engineering at Princeton University. His research on networking received the 2013 Alan T. Waterman Award, the highest honor to US young scientists and engineers. His textbook “Networks: Friends, Money and Bytes” and online course reached 250,000 students since 2012. He founded the Princeton EDGE Lab in 2009, which bridges the theory-practice gap in edge networking research by spanning from proofs to prototypes. He co-founded a few startups in mobile, IoT and big data areas and co-founded the Open Fog Consortium. Chiang is the Director of Keller Center for Innovations in Engineering Education at Princeton University and the inaugural Chairman of Princeton Entrepreneurship Council.