This section describes technology and trends influencing the Enterprise Data Center. For large enterprises with a significant number of servers, a dedicated Enterprise Data Center provides employees, partners, and customers with access to data and resources to effectively work, collaborate, and interact. Historically, most Enterprise Data Centers grew rapidly as organizational requirements expanded. Applications were implemented as needed, often resulting in underutilized, isolated infrastructure silos. Each silo was designed based on the specific application being deployed, so a typical data center supported a broad assortment of operating systems, computing platforms, and storage systems, resulting in various application “islands” that were difficult to change or expand and expensive to manage, integrate, secure, and back up.

This server-centric data center model is evolving to a service-centric model, as illustrated in Figure below This evolution includes the following:

■ The deployment of virtual machine software, such as VMware and Xen, which breaks the one-to-one relationship between applications and the server hardware and operating system on which they run. Virtual machine software allows multiple applications to run on a single server, independent of each other and of the underlying operating system.

■ The removal of storage from the server, consolidating it in storage pools. Networked storage (such as storage area networks [SAN]) allows easier management, provisioning, improved utilization, and consistent recovery practices.

■ The creation of pools of one-way, two-way, or four-way servers that can be pooled and provisioned, on demand.

■ The consolidation of I/O resources so that the I/O can be pooled and provisioned on demand for connectivity to other servers, storage, and LAN pools.

The resulting service-centric data center has pooled compute, storage, and I/O resources that are provisioned to support applications over the data center network. Because the network touches and can control all the components, the network can be used to integrate all the applications and services; network technology actively participates in the delivery of applications to end users.