Cloudlet-based Edge Computing
Gabriel Wearable Cognitive Assistance using Cloudlets
is a new paradigm in which the resources of a small data center are
placed at the edge of the Internet, in close proximity 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:
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.
- only soft state:
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
- powerful, well-connected and
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
- 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.
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
mention of cloudlets in the literature. Gabriel is an angel who looks out for you.