And although some companies may use private clouds as an entry point and then transition to public clouds, EMC sees the Private Cloud as much more than just a staging ground for public clouds. EMC and partners want to help you create a flexible set of IT resources by federating your private clouds with external infrastructures provided by third-party providers.

Not surprisingly, EMC’s contribution is concentrated on providing storage, backup, archiving, and security (from RSA) to support the data centers in a private cloud environment. When all IT resources (servers, network, and storage) are pooled in the virtualized data center model, many things need to change.

Storage must be designed and managed differently. For example, many EMC products require a dedicated pair of servers, and this requirement won’t fly in a virtualized environment. New tools and processes are required to plan and manage IT resources and ensure information security. For example, your company can use EMC’s Atmos cloud storage service to build a scalable internal storage cloud, and then tie it to an external cloud storage service. Cisco brings the network and capability of building a scalable network to the mix. VMware’s vSphere, as described later in this section, is the cloud operating system.

Source of Information : cloud computing for dummies 2010 retail ebook distribution