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Elijah   Cloudlet-based Edge Computing

Gabriel  Wearable Cognitive Assistance using Cloudlets

People Development
Videos and Press

Edge computing is a new paradigm in which the resources of a small data center are placed at the edge of the Internet, in close roximity to mobile devices, sensors, and end users. Terms such as "cloudlets," "micro data centers," and "fog" have been used in the literature to refer to these small, edge-located data centers. They all represent counterpoints to the theme of consolidation and massive data centers that has dominated discourse in cloud computing.  A group of companies are collaborating with Carnegie Mellon University in the Open Edge Computing Initiative to catalyze an open ecosystem for cloudlet-based edge computing.  The January 2017 paper "The Emergence of Edge Computing" explains this new computing paradigm.

A cloudlet is a new architectural element  that arises from the convergence of mobile computing / IoT  and cloud computing.  It represents the middle tier of a 3-tier hierarchy:  mobile or IoT device --- cloudlet --- cloud.   A cloudlet can be viewed as a "data center in a box" whose  goal is to "bring the cloud closer".   

A cloudlet has four key attributes:
  • only soft state:   It is does not have any hard state, but may contain cached state from the cloud.  It may also buffer data originating from a mobile device (such as video or photographs) en route to safety in the cloud.  The avoidance of hard state means that each cloudlet adds close to zero management burden after installation:  it is entirely self-managing.   
  • powerful, well-connected and safe:  It possesses sufficient compute power (i.e., CPU, RAM, etc.) to offload resource-intensive computations from one or more mobile devices.  It has excellent connectivity to the cloud (typically a wired Internet connection) and is not limited by finite battery life (i.e., it is plugged into a power outlet).    Its integrity as a computing platform is assumed; in a production-quality implementation this will have to be enforced through some combination of tamper-resistance, surveillance, and run-time attestation.
  • close at hand:  It is logically proximate to the associated mobile devices. "Logical proximity" is defined as  low end-to-end latency and high bandwidth (e.g., one-hop Wi-Fi).   Often, logical proximity implies physical proximity.  However, because of "last mile" effects, the inverse may not be true: physical proximity may not imply logical proximity.
  • builds on standard cloud technology: It encapsulates offload code from mobile devices in  virtual machines (VMs), and thus resembles classic cloud infrastructure such as Amazon EC2 and OpenStack.  In addition, each cloudlet has functionality that is specific to its cloudlet role.
The low latency and rich compute of cloudlets enables a new class of applications called wearable cognitive assistance that seamlessly enhance a user's ability to interact with the real world around him or her.   A PaaS (platform as a service) layer on cloudlets called Gabriel supports this new class of applications.    Gabriel applications have the look and feel of augmented reality (AR) combined with the algorithms and compute requirements of artificial intelligence (AI).  Here is an early thought piece on augmenting cognition dating back to 2004, that imagined such a future.   This 90-second excerpt​ from the October 9, 2016 CBS 60 Minutes special edition on Artificial Intelligence highlights one such application.  The "Videos and Press" link above takes you to a page with links to many more videos of Gabriel applications.

For background information and rationale for cloudlets, see the 2009 paper  "The Case for VM-based Cloudlets in Mobile Computing"   As the paper explains, cloudlets are the enabling technology for a new genre of resource-intensive but latency-sensitive mobile applications that will emerge in the future. 

"Bringing the cloud closer" also improves the survivability of mobile computing in hostile environments such as military applications and disaster recovery.  Easily-disrupted critical dependence on a distant cloud is replaced by dependence on a nearby cloudlet and best-effort synchronization with the distant cloud.   The 2013 paper
"The Role of Cloudlets in Hostile Environments" explores these issues.

The name "Elijah" was inspired by the earliest mention of cloudlets in the literature.   Gabriel is an angel who looks out for you.

 Contact: Professor Mahadev Satyanarayanan


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