SaaS Level in the Stack – Cloud Infrastructure

SaaS (software as a service) Levels refers to the various architectural layers that provide the framework for SaaS delivery. There are three layers in a SaaS Stack,as follows:

  • Top Level – where the SaaS Solution resides
  • Middle Level – where the PaaS (platform as a service) or Middleware Solution resides
  • Bottom Level – where the core technologies (infrastructure) that provide the foundation for cloud service delivery reside

There are fewer providers on the bottom level of the SaaS Stack, than on the middle level of the SaaS Stack; and there are fewer providers on the middle level of the SaaS Stack than on the top level of the SaaS Stack. This is because the cost of entry is lower on the top of the SaaS Stack, meaning that becoming a SaaS provider / ISV (independent software vendor) requires a lower capital investment than what is required to enter the marketplace as a PaaS or IaaS (infrastructure as a service) provider.

Hosted Infrastructure (Bottom Level)

The bottom SaaS Level forms the foundation that PaaS solutions and SaaS solutions need to function. This level includes physical infrastructure & computing resources, such as servers, processing capacity, storage capacity, etc. that may be delivered as a service to the cloud, to facilitate PaaS and/or SaaS delivery. Note: The infrastructure contained within this layer can physically exist anywhere, as the resources are being delivered as a service via the Internet.

Hosted Platforms (Middle Level)

The middle SaaS Level provides an operational environment for the management, development and deployment of SaaS solutions. Middleware makes computing resources available to users in a virtual manner through various methods of allocation. Platform services such as SaaS provisioning, SaaS Metering, SaaS Billing and SaaS Performance Management are all executed at this level.

Hosted Applications (Top Level)

The top SaaS Level provides a software application as a service to its consumers. This level facilitates the delivery of software to end users via web based interfaces which are accessible through a number of different web browsers. Hosted (SaaS) applications may logically reside in a public cloud, a private cloud, a community cloud or a hybrid cloud.