A pure private cloud achieves some of the capital cost reduction and reuse benefits with none of the control, security, reliability or ownership risks.
A hybrid cloud begins to achieve improved time to market, provisioning, and lower capital costs. However, business risk for security, reliability and ownership increases. Competitive risks are contained by keeping core business information systems on premise.
The external public cloud shown here achieves the greatest cost, time to market and maintenance benefits but incurs the security, reliability and competitive risks. Here we can see that the Enterprise Perimeter has shrunk down and no longer contains core business information systems.
In Figure (a), the Enterprise is shown making its first baby step towards cloud orientation by utilizing virtualized infrastructure to save capital costs and re-use hardware as needed.
In Figure (b) the Enterprise expands on this initial architecture by utilizing an external software platform (SaaS) for a well-defined business need such as customer relationship management and augments its business critical information systems with additional platform services for increased scalability and storage. In this phase, cloud bursting may also occur where the Enterprise begins to utilize an infrastructure provider for short-lived projects requiring a few isolated servers. This is represented in Figure (b) as the end user reaches out across the Enterprise perimeter to a SaaS vendor and IaaS provider and the line connecting the existing enterprise information systems to the PaaS cloud service provider, which could be thought of as a set of XML web services (SOAP or REST based) designed to support the core information systems.
In Figure (c) we can see how the strong assumption for the public cloud plays out. Here the Enterprise perimeter has shrunk to near-zero and more SaaS and IaaS services are employed to fulfill all critical business needs. We may imagine that core business critical information systems include supply chain, enterprise resource planning, accounting, customer management, business intelligence and order management. These core information systems are not SaaS applications but really the same systems that were running on-premise but moved to the cloud infrastructure for cost and maintenance benefits. Here the traditional enterprise perimeter is gone, but has been replaced with a virtual enterprise perimeter, which is the fuzzy thread that loops throughout the architecture. The “fuzziness” of this new perimeter is where the increased business risk comes into the picture. Here extent of the perimeter is actually unknown, or very difficult to know as it cuts across the multi-tenant, shared architecture utilized by nearly all cloud service providers, whether they are software, infrastructure or platform
Next, Business Barriers related to this fuzzy perimeter.