Licenses acquired under the SPLA are monthly subscription licenses.
The following are the licensing models:
Per Processor: Each Processor License allows an unlimited number of users to access the product that is installed on that processor for products licensed through a per-processor model. Examples of products licensed through a per-processor model are Windows Server, Microsoft SQL Server, and Microsoft Dynamics ERP.
Per Subscriber: A Subscriber Access License (SAL) is required for each unique individual user or device that is authorized to access or otherwise use the licensed products. When using the SAL option, a separate Server License is not needed. Examples of products licensed with a SAL are the Windows Server operating system, Microsoft SQL Server database software, Microsoft Exchange Server, Microsoft Office, and Microsoft Dynamics® business software (CRM). SALs for Software Assurance are available for some products to be assigned to customers who have previously purchased on-premises Client Access Licenses (CALs) and who continue to maintain Software Assurance on those CALs. With SALs for Software Assurance, these customers can migrate to the equivalent SPLA service at a discounted rate. SPLA partners can purchase SALs for Software Assurance, which are price advantaged versus regular SALs, for these customers.
Please note that not all products are available in both license models.