Software licensing models are the families of license metrics that software publishers use to measure, and charge for, the use of their products. A metric is the unit in which a software license is expressed: a processor core, a named person, a device, an employee, a unit of consumption. The same deployment can require very different quantities of licenses depending on which metric applies and how the publisher defines it, so the metric is the starting point for every calculation in software asset management.
There is no universal taxonomy. Each publisher names and defines its own metrics, and similar-sounding names can carry different rules: Oracle’s Named User Plus, IBM’s Authorized User and Microsoft’s User CAL all count people, but under different definitions and minimums.[2][5][8] The international entitlement schema standard, ISO/IEC 19770-3, notes that a standard structure for entitlements may encourage the industry to normalize the names and details of different entitlement types.[1] The families below are a descriptive grouping used in this wiki; the binding definitions are always the publisher’s, and are recorded row by row in the Vendor License Metrics catalog.
History
Metric families reflect the computing environments for which they were designed. Access-based metrics license people or devices that use shared server software; in Microsoft’s Server/CAL models, for example, the server is licensed by server or core and access is licensed separately through client access licenses.[8] Capacity metrics license the server itself, and as multi-core processors, virtualization and cloud computing made hardware capacity harder to define, publishers introduced capacity units weighted by processor technology, rules for counting virtual processors, and “sub-capacity” terms that depend on approved measurement tools.[4][5][6] Software as a service brought time-bound subscriptions, and more recently consumption models priced in credits or tokens.[7][10][11] Because publishers revise and retire definitions over time, the Vendor License Metrics catalog keeps superseded definitions as separate rows from current ones.
Scope and definitions
Comparison of metric families
| Family | What is counted | Typical rules to check | Catalog examples |
|---|---|---|---|
| Processor, core and capacity | Physical processors, cores, weighted capacity units or virtual CPUs available to the software | Core factors or weights, per-processor and per-server minimums, virtualization and sub-capacity rules | Oracle Processor, Microsoft Per Core, IBM PVU, IBM VPC, Red Hat vCPU |
| Named user | Each individual authorized to use the software | Whether authorization or actual use counts; devices and non-human users; minimums per processor; reassignment limits | Oracle Named User Plus, IBM Authorized User, SAP Named User, Adobe Named User |
| Concurrent user | Peak number of simultaneous users or sessions | Measurement method; who may be counted | IBM Concurrent User, Oracle Concurrent User, SAP Concurrent Sessions, Citrix Concurrent |
| Device | Each device that runs or accesses the software | Definition of a device; shared and non-human devices | Microsoft Device CAL, Oracle Connected Device, Adobe Device-Based Software License, ServiceNow Devices |
| Server and instance | Each server, installation, instance or virtual server | Whether virtual copies count separately | Microsoft Server license, IBM Install, IBM Virtual Server |
| Site, enterprise and headcount | All employees, all users at a site, or the whole organization | Definition of employee (contractors, outsourcers); measurement date | Oracle Employee, Cisco Employee Count, Cisco Covered Site, Red Hat FTE |
| Subscription and consumption | Time-bound rights, or measured usage drawn down from credits, tokens or capacity | Rate cards, true-up and overage terms, what consumes a unit | ServiceNow Subscription Unit, Salesforce Flex Credits, Autodesk Flex Token, IBM RVU, Broadcom per TiB |
| Feature and module | Access to specific functionality on top of a base license | Base plus add-on dependencies | Microsoft Base CAL, Microsoft Additive CAL, SAP Digital Access |
| OEM | A license supplied with, and tied to, a hardware device | Transfer and hardware replacement rules | (no dedicated catalog metric; see text) |
Entitlements and metrics in standards
ISO/IEC 19770-3 defines a transport format for encapsulating software entitlements, including their associated metrics, and states that the original license documentation remains legally definitive over any such encapsulation.[1] ISO/IEC 19770-4 defines an information structure for resource utilization measurement, the usage data against which consumption and capacity metrics can be compared.[13]
How it works
Processor, core and capacity units
Capacity metrics license the computing power on which the software runs, regardless of how many people use it. They are typical of databases, middleware and operating systems.
- Processor with core factor. Oracle’s Processor metric counts all processors where the programs are installed or running; the number of licenses is the total number of cores multiplied by a core factor from Oracle’s Processor Core Factor Table, with fractions rounded up.[2] Catalog row: Oracle Processor; article: Oracle Database licensing.
- Per core with minimums. Microsoft licenses SQL Server and BizTalk Server Per Core, and Windows Server under a Per Core/CAL model. Windows Server requires at least 16 core licenses per server and eight per physical processor; SQL Server requires at least four core licenses per physical processor, and core licenses are sold in packs of two.[3] Catalog rows: Microsoft Per Core, Microsoft Per Core/CAL; articles: SQL Server licensing, Windows Server licensing. Broadcom’s VMware subscriptions are also licensed per core (Broadcom per Core; see VMware vSphere and VCF), as are some SAP runtime products (SAP Cores).
- Weighted capacity units. IBM’s Processor Value Unit is a unit of measure used to differentiate licensing on distributed processor technologies, with the number of PVUs per core set by processor vendor, brand, type and model.[4] IBM’s Virtual Processor Core metric instead counts a core in an unpartitioned physical server or a virtual core assigned to a virtual server.[5] Catalog rows: IBM PVU, IBM VPC; article: IBM Passport Advantage.
- Sockets and virtual CPUs. Some subscriptions count occupied sockets or virtual CPUs, for example Red Hat Socket-pair, Red Hat vCPU and Citrix Per socket; see Red Hat Enterprise Linux and OpenShift and Citrix licensing.
Virtualization is the main complication. IBM permits eligible products to be licensed on the virtualization capacity available to them (sub-capacity) rather than the full physical server, but only where the customer meets the agreement’s reporting requirements; otherwise full capacity applies.[6] Rules for public clouds are collected in Cloud BYOL.
Named user
Named user metrics count individuals who are permitted to use the software, whether or not they use it at a given time.
- Oracle’s Named User Plus is an individual authorized to use the programs, whether or not actively using them; non-human operated devices that can access the programs are counted too, and where multiplexing hardware or software is used the number must be measured at the multiplexing front end. For some products, including Oracle Database Enterprise Edition, a minimum of 25 Named Users Plus per Processor applies.[2] Catalog row: Oracle Named User Plus.
- IBM’s Authorized User is a unique person given access to the program; each needs a dedicated entitlement that cannot be shared or reassigned other than by permanent transfer.[5] Catalog row: IBM Authorized User.
- In Microsoft’s Server/CAL models, the server software is licensed by server or core and access is licensed separately through client access licenses. A User CAL lets the licensed user access the server software from any device.[8] Microsoft’s glossary defines a Licensed User as the single person to whom a license is assigned.[7] Catalog rows: Microsoft User CAL, Microsoft User SL; article: Microsoft 365 and Online Services.
- Business applications often define several user types at different prices, such as the SAP user types in SAP Named User and Digital Access (SAP Named User), ServiceNow’s fulfiller user type (ServiceNow Fulfiller User; see ServiceNow user and subscription unit) and single-user desktop subscriptions such as Adobe Named User and Autodesk Single User (see Adobe named-user licensing and Autodesk single-user and Flex).
Named licenses may also limit how often they can be moved. Microsoft allows reassignment of a license to another user or device, but not within 90 days of the last reassignment.[14]
Concurrent user
Concurrent metrics count the peak number of people or sessions using the software simultaneously. IBM’s Concurrent User is a person accessing the program at any particular point in time, and entitlements must cover the maximum number of simultaneous users.[5] Definitions can restrict who may be counted: Oracle’s Concurrent User metric is limited to the licensee’s customers or prospective customers and excludes its employees and business partners.[2] Catalog rows: IBM Concurrent User, Oracle Concurrent User, SAP Concurrent Sessions, Citrix Concurrent, Autodesk Multi User.
Device
Device metrics count the machines on which software runs or from which it is accessed. Microsoft’s glossary defines a Licensed Device as a single physical hardware system to which a license is assigned, and a Device CAL permits any user to access server software from the licensed device.[7][8] Device metrics also appear in the Internet of Things and network equipment, for example Oracle Connected Device, Cisco Device and ServiceNow Devices (see Cisco software subscription and Flex). Catalog rows: Microsoft Device CAL, Adobe Device-Based Software License.
Server and instance
Some products are licensed per installation or per server regardless of capacity or users. IBM’s Install metric counts each installed copy on a physical or virtual disk made available for execution, and its Virtual Server metric requires an entitlement for each virtual server regardless of cores.[5] Catalog rows: IBM Install, IBM Virtual Server, Microsoft Server license.
Site, enterprise and headcount
Enterprise metrics license a whole population instead of counting deployments. Oracle’s Employee metric counts all full-time, part-time and temporary employees plus agents, contractors and consultants who have access to, use or are tracked by the programs, and states that the number of licenses depends on the number of employees and not on actual users; certain outsourcers’ staff must also be counted.[2] Catalog rows: Oracle Employee (see Oracle Java SE), Cisco Employee Count, Red Hat FTE, and site-based terms such as Cisco Covered Site.
Enterprise-wide coverage is also offered through agreements rather than metrics. Microsoft describes its Enterprise Agreement as aimed at organizations with 500 or more users or devices, for a minimum three-year period, with a single organization-wide agreement under which users, devices and products can be added during the term.[9] Unlimited-deployment agreements are described in Oracle ULA and PULA.
Subscription and consumption
A subscription grants rights for a defined period rather than perpetually; Microsoft’s glossary defines a subscription license as one that allows access to software or a hosted service for a defined period of time.[7] Subscriptions can be counted in any of the other metrics (users, cores, devices); what distinguishes them is duration. United States federal guidance distinguishes perpetual and term licenses from maintenance and from subscription services.[15]
Consumption models charge for measured usage. Salesforce describes Flex Credits as a single unit of payment spent across its consumption services, bought pay as you go, against a committed baseline, or prepaid.[10] Autodesk Flex lets customers pre-purchase tokens that are consumed at a daily rate, varying by product, when a user accesses a product.[11] Catalog rows: Salesforce Flex Credits, Autodesk Flex Token, ServiceNow Subscription Unit, Microsoft Dataverse Capacity. Resource-based metrics such as IBM’s Resource Value Unit, which counts units of a specific resource used or managed by the program, and IBM’s Terabyte metric belong to the same family.[5] See Salesforce user and consumption licensing.
Feature and module
Many products license a base right and separately priced functionality on top of it. In Microsoft’s CAL model, a Base CAL is the minimum requirement for access to a server product, and advanced functionality requires an Additive CAL in addition to the Base CAL.[8] Catalog rows: Microsoft Base CAL, Microsoft Additive CAL. Some publishers license particular kinds of use separately from users; SAP’s document-based SAP Digital Access metric is described in SAP Named User and Digital Access.
OEM
Original equipment manufacturer (OEM) licenses are supplied pre-installed with hardware and tied to it. A Microsoft guide on OEM licensing states that OEM software may not be transferred to another machine, even if the original device is retired, and that replacing a desktop’s motherboard (other than for a defect) requires a new operating system license.[12] The same guide notes that Windows desktop licenses bought through Microsoft Volume Licensing are upgrades that require an eligible underlying license, generally an OEM license.[12] The catalog does not currently hold a dedicated OEM metric row.
Standards and frameworks
No standard prescribes which metrics publishers must use. The ISO/IEC 19770 family instead provides data structures for describing entitlements (Part 3) and resource utilization (Part 4), so that entitlements and measured usage can be exchanged and reconciled consistently.[1][13] In this wiki, metric definitions are recorded only from vendor documents, as set out in House rules.
Relationship to other disciplines
The metric determines what software asset management must measure: cores and virtualization topology for capacity metrics, identity and access records for user metrics, device inventories for device metrics, and usage telemetry for consumption metrics. This makes license metrics a point of contact between SAM, hardware and cloud asset data in IT asset management, identity management, and FinOps.
Criticism and challenges
Several features of metric design make license positions difficult to compute:
- Divergent definitions. Names such as “user”, “processor” or “device” mean different things for different publishers and, sometimes, for different products from the same publisher.[2][5]
- Minimums and multipliers. Per-processor user minimums, core factors and per-server minimums mean that the licensed quantity can exceed actual use.[2][3]
- Measurement dependency. Some metrics can be counted only with specified tools or reports, such as IBM sub-capacity reporting.[6]
- Bundling. GAO found that several products may be bundled under a single license, which made it unclear which products under agencies’ most widely used licenses were actually used most.[16]
- Change over time. Publishers retire and redefine metrics, so contracts signed at different dates can carry different rules for the same product. The catalog marks superseded definitions separately.
Out of scope
This article summarizes metric families and does not replace the definitions in each publisher’s documents or the executed agreement. Per-product counting rules, floors and virtualization policies are in the vendor articles, and every metric definition is in its Vendor License Metrics row. Prices are not covered.