Infrastructure as a Service or IaaS refers to a type of cloud computing which offers virtual computing resources across the Internet. It is one of the key categories of cloud computing, the other two being Software as a Service or SaaS and Platform as a Service or PaaS. Like the other cloud computing models, the IaaS also provides users with access to resources in a virtualized environment. In this case, it is the hardware or more specifically the computing infrastructure. So, the IaaS will provide the network connections, server space, IP addresses and bandwidth, load balancers etc. Like the other two forms of cloud computing, IaaS may be used by client enterprises for creating affordable and highly scalable IT solutions. All the responsibilities of managing the underlying servers in this case are outsourced to the vendor. When the clients business operations fluctuate, they can access cloud resources. So the IaaS basically offers resources to clients whenever these become necessary for handling traffic; so there is no wasted capacity. You do not have to buy hardware for storage; the underlying hardware supporting the IaaS is maintained by the vendor. It provides utility style costing where services can be accessed depending upon demands. Services can also be accessed from any location provided there is Internet connectivity. There is also no one point of failure because even if a single server malfunctions, other servers remain unaffected.