SDN: Software Defined Networks

Chapter 6. Data Center Concepts and Constructs

Introduction

Prior to the existence of data centers, computing, storage, and the networks that interconnected them existed on the desktop PCs of enterprise users. As data storage grew, along with the need for collaboration, departmental servers were installed and served this purpose. However, they provided services that were dedicated only to local or limited use. As time went on, the departmental servers could not handle the growing load or the widespread collaborative needs of users and were migrated into a more centralized data center. Data centers facilitated an ease of hardware and software management and maintenance and could be more easily shared by all of the enterprise’s users.

Modern data centers were originally created to physically separate traditional computing elements (e.g., PC servers), their associated storage (i.e., storage area networks or SANs) and the networks that interconnected them with client users. The computing power that existed in these types of data centers became focused on specific server functionality, such as running applications that included mail servers, database servers, or other enterprise IT applications.

It was around 10 years ago that an interesting transformation took place. A company called VMware had invented an interesting technology that allowed a host operating system, such as one of the popular Linux distributions, to execute one or more client operating systems (e.g., Windows) as if they ...