EA Toolsets project : TogafMeta

TOGAF metamodel examples

Structure of TOGAF metamodel

In addition to the usual IT-centric 'four architectures', the TOGAF metamodel includes a section on high-level requirements and change-management. All of these are split into a 'core' group and a set of 'extensions', as indicated with [..] in the following summary:

Architecture principles, vision, requirements, roadmap
- Principle [core], Constraint [core], Assumption [core], Requirement [core], Gap [core], Work Package [core], Capability [core]
Business Architecture
- Motivation: Driver [motivation], Goal [motivation], Objective [motivation], Measure [governance]
- Organisation: Organisational Unit [core], Actor [core], Role [core], Location [infrastructure consolidation]
- Function: Function [core], Business Service [core], Process [core], Contract [governance], Service Quality [governance], Event [process], Control [process], Product [process]
Data Architecture
- Data Entity [core], Logical Data Component [data], Physical Data Component [data]
Application Architecture
- Information System Service [services], Logical Application Component [core], Physical Application Component [infrastructure consolidation]
Technology Architecture
- Platform Service [core], Logical Technology Component [infrastructure consolidation], Physical Technology Component [core]

Core and extensions

The TOGAF metamodel entities can be mapped to this metamodel's category-schema as follows:

Core

Principle - sub-type of decision, typically either >principle or >heuristic, linked in trails devolving from row-0 Value and/or Vision
Constraint - sub-type of decision
Assumption - sub-type of decision
Requirement - sub-type of decision
Gap - (strictly speaking, is a decision about architectural change, but doesn't really belong in any structural view - it's about change to structure, hence is more an annotation to structure or interpretation of structure, not structure itself)
Work Package - (as for Gap - is more about change to structure than structure itself, hence is somewhat outside of the categorisation schema, though its end-product should include new capability, new asset, new service and so on)
Capability - (different meaning of 'capability' here - is an end-product of change, not structure - the end-product is a capability or service, but in itself it is not a 'capability' within the terms of the categorisation schema)
Organisational Unit - aggregation of location>relational (and possibly >physical), capability, service, asset etc viewed as a compound, collective actor and role
Actor - asset>relational, or somewhat blurry composite of asset>physical, capability>virtual and function>virtual as 'actor>virtual'
Role - cluster of related capabilities linked to a specific business-purpose (decision) - in TOGAF, would always be linked to an Actor and/or Organizational Unit
Business Service - a service governed (i.e. linked to) one of this organisation's own Organizational Units
Function - a service which may or may not be governed exclusively by this organisation (i.e. identical to Business Service other than in its governance rules)
Process - choreographed sequence of services, which may itself be viewed as an abstract function and/or service
Data Entity - asset>virtual, typically at row-3 or above ("an encapsulation of data that is recognized by a business domain expert as a thing" - see also Logical Data Component and Physical Data Component)
Logical Application Component - service>virtual, typically at row-3 or above (because 'logical')
Platform Service - a composite of asset>physical (physical infrastructure) and service>virtual, typically described at row-3 or above
Physical Technology Component - a composite of asset>physical (physical infrastructure) and service>virtual, typically described at row-4 or below

Motivation extension

Driver - a decision or constraint
Goal - composite of decision (the description of the desired goal and its underlying reasons) and event (the conditions that identify achievement of the goal), typically at row-2 or above
Objective - a 'sub-Goal' - composite of decision and event, typically at row-3 or below, linked to a Goal or a higher Objective

Infrastructure Consolidation extension

Location - a location, implied to be >physical but could also be >relational and/or >virtual
Physical Application Component - service>virtual, typically at row-4 or below (because 'physical')
Logical Technology Component - a composite of asset>physical (physical infrastructure) and service>virtual, typically at row-3 or above (because 'logical')

Governance extension

Measure - composite of asset>virtual and decision, probably also including service>virtual
Contract - complex composite and/or aggregate of decision and asset>relational linked to the respective services, values etc ("an agreement between a service consumer and a service provider that establishes functional and non-functional parameters for interaction")
- note that this may be an example of where an entity may link to a relation rather than to another entity, because this applies to the interface between the two services
Service Quality - complex composite as encapsulation of links to decisions and values ("a preset configuration of non-functional attributes that may be assigned to a service or service contract")

Process Modelling extension

Event - an event of any appropriate kind
Control - composite of decision and service
Product - asset or service linked to value linked in turn to asset>relational (i.e. pointer to end-customer)

Data Modelling extension

Logical Data Component - asset>virtual at row-3 (because 'logical')
Physical Data Component - asset>virtual at row-4 or below (because 'physical')

Services extension

Information System Service - service>virtual (i.e. composite of function>virtual, capability>virtual and respective 'actor>virtual')

Note that, as is usual in IT-centric 'enterprise-architecture', there are no entities tomodel manual processes, machine-based processes or non-IT physical technology. Most of the entities above, however, can be re-used for such purposes if aligned or linked to the respective members of this metamodel's categorisation-schema.