Without the cloud, the IoT growth and market would be non-existent. Essentially, billions of endpoint devices that were historically dumb and not connected would need to manage themselves without the ability to share data or aggregate data. Billions of small embedded systems add no marginal value for customers. The value of the IoT is in the data it produces—not at a single endpoint but in thousands or millions of endpoints. The cloud provides the ability to have simple sensors, cameras, switches, beacons, and actuators participate in a common language with each other. The cloud is the common denominator of the data currency.

The ubiquitous cloud metaphor refers to an infrastructure of computing services that are generally on-demand. The pool of resources (computing, networking, storage, and the associated software services) can dynamically scale up or down based on load average or quality of service. Clouds are typically large data centers that provide outward facing services to customers on a pay-for-use model. These centers provide the illusion of a single cloud resource while in fact there may be many geographically dispersed resources being used. This gives the user a sense of location independence. Resources are elastic (meaning scalable) and services are pay-for-use, generating a recurring revenue stream for the provider. Services that run in the cloud differ in their construction and deployment from traditional software. Cloud-based applications can be developed and deployed faster and with fewer degrees of environmental variability. Thus, cloud deployment enjoys rapid feature velocity.

There are accounts that the first description of the cloud originated at Compaq in the mid-1990s, where technology futurists predicted a computing model that moved computing to the web versus on host platforms. Essentially, this was the basis of cloud computing, but it wasn't until the advent of certain other technologies that cloud computing became practical for the industry. The telecommunications industry traditionally was built on a point-to-point system of circuits. The creation of VPNs allows for secure and controlled access to clusters and has enabled private-public cloud hybrids to exist. 

This chapter studies cloud architecture and the following areas:

• A formal definition of cloud topologies and vernacular
• An architectural overview of OpenStack cloud
• A study of the fundamental problem with cloud-only architecture
• Fog computing overview
• OpenFog reference architecture
• Fog computing topologies and use cases

Throughout the chapter, several use cases will be talked about so you can understand the impact of big data semantics on IoT sensor environments.