Infrastructure as a Service (IaaS) is a cloud computing model that provides infrastructure-level resources (e.g. servers, storage, DNS, load balancing, firewalls, IP addresses, VLANs) on demand. Contrast with the [paas] and [saas] tags.
Infrastructure as a Service (IaaS), in contrast with traditional procurement models, provides infrastructure-level resources on a subscription basis through the cloud. This allows network and computing resources to be quickly deployed and dynamically scaled on demand.