1. Subscriber Access License (SAL) Model
The SAL model works on the principle of authorizing individual subscribers.
- Definition: A SAL is mandatory for every distinct person to whom the service is rendered and who has authorization to access it within a month.
- No Server License Required: If you opt for the SAL model, there's no need to purchase a separate Server License.
- Product Limitations: It's important to note that not every product can be licensed under the SAL mode.
- Examples: Some of the notable products available for licensing via SAL are Microsoft Exchange Server, Skype for Business, SQL Server Standard, and SharePoint.
- Flexibility for Subscribers: Subscribers are not restricted by the number of servers they can access.
- Scalability for Service Providers: Service providers have the freedom to expand their infrastructure ("scale out").
- Cost-Efficiency: Service providers can initiate their services with minimal financial outlay.
2. Core Licensing Model for Operating Systems (Windows Server)
This model revolves around the physical cores of a licensed server.
- Licensing Principle: Customers can use the server software on a Licensed Server as long as they possess the appropriate number of Server licenses. This number corresponds to the total physical cores of the Licensed Server, with a caveat that a minimum of 8 Licenses per Physical Processor must be acquired.
- Standard vs. Datacenter Editions:
- Standard Edition: This edition allows the software's use in one Operating System Environment (OSE) on the Licensed Server. Additionally, it facilitates the execution of one Running Instance of the software in the Physical OSE on the Licensed Server, provided the Physical OSE exclusively hosts and manages the Virtual OSE. To operate the software in an additional OSE on the same Licensed Server, extra Standard Edition Licenses equal to the number specified must be assigned.
- Datacenter Edition: This variant provides the freedom to use the server software in an unlimited number of OSEs on the Licensed Server.
3. Core Licensing Model for Applications (i.e. SQL Server)
This model targets the application layer and offers two licensing alternatives: By Physical Core on a Server or By Individual Virtual OSE.
- Licensing by Physical Core on a Server:
- A sufficient number of Licenses (equivalent to the number of Physical Cores on the Licensed Server, with a minimum requirement of four per core Licenses per Physical Processor) must be acquired.
- Enterprise Editions: Customers can run any number of the server software's Running Instances on the Licensed Server, either in the Physical OSE or in multiple Virtual OSEs.
- Other Editions: The software can run only in the Physical OSE on the Licensed Server.
- Server Licenses (per core) – Licensing by Individual Virtual OSE:
- The software can run in any Virtual OSE on the Licensed Server, given that enough Licenses are acquired. The number of Licenses needed equals the total Virtual Cores in the Virtual OSE, with a minimum of four Licenses per Virtual OSE.
- If a Virtual Core links to multiple Hardware Threads at any time, a License for every mapped Hardware Thread is essential.
4. Host/Guest Licensing Model
The Host/Guest model divides the licensing needs into two categories: those for the host environment (the underlying physical infrastructure or "Host Fabric") and those for the virtualized environments or "guest Virtual OSEs" (Operating System Environments) running atop that infrastructure.
- Dual Licensing Requirement: This model mandates licenses for both the host and guest environments. Moreover, Subscriber Access Licenses (SALs) become essential for users leveraging specific functionalities within the guest software.
- Host Licenses: Prior to utilizing software for the Host Fabric, the customer must assign a host license for every Physical Processor present in the server that constitutes its Host Fabric. A server that has been duly assigned the requisite number of licenses is designated as a “licensed host server.”
- Host Software: Any software licensed under host licenses falls under the category of “host software.” Upon the assignment of necessary host licenses, the customer gains the ability to run countless instances of the host software, primarily to deploy, manage, configure, and operate its Host Fabric. However, the use of this software is governed by restrictions outlined in the Product Specific License Terms.
- Guest Software: Software licensed under the guest licenses umbrella is termed “guest software.” This comprises both server software and additional supplementary software.
- The guest server software is restricted to running solely within a Virtual OSE that is hosted using the Hyper-V virtualization functionality provided by the Microsoft Cloud Platform Suite on a licensed host server.
- For each guest software license acquired by the customer, they are permitted to run a singular instance of the guest server software. In addition to this, they can run multiple instances of the extra or "additional" software. This additional software can operate both in Physical OSEs and Virtual OSEs across various devices. The primary condition is that its usage should be in tandem with the guest server software.
In conclusion, SPLA licensing offers flexibility and scalability to service providers and ensures subscribers get value for their investment. By understanding the intricacies of these models, organizations can ensure compliance and optimize their licensing strategy.