Cloud computing is a very wide term and doesn’t cover all IT infrastructure. There are bigger challenges of migrating complex infrastructures and computes to virtual environment or cloud. You will need to consider a lot of variations while preparing a public or private cloud computing. The consideration includes increasing complexity and ever-growing data or databases.
Also, you need to know which applications need to be networked and what operating system you would probably need to run the environment. Technology have evolved over a period of time, but placement of those technologies at the right place is important or you would be loosing a lot of business due to downtime, loss of data and other factors.