Implementation and Migration Layer

The central behavioral element is a work package. A work package is typically not a continuously ongoing activity, but has a start and an end. These may be modeled as attributes. It produces a well-defined set of results, typically modeled as goals, outcomes, or deliverables. The work package element can be used to model sub-projects or tasks within a project, complete projects, programs, or project portfolios. In an Agile context, a work package can be used to model the work performed in an Agile iteration (e.g., sprint) or higher level increment.

Conceptually, a work package is similar to a business process, in that it consists of a set of causally-related tasks, aimed at producing a well-defined result. However, a work package is a unique “one-off” process. Still, a work package can be described in a way very similar to the description of a process.

Work packages produce deliverables. These may be results of any kind; e.g., reports, papers, services, software, physical products, etc., or intangible results such as organizational change. A deliverable may also be the implementation of (a part of) an architecture.

Often, deliverables are contractually specified and in turn formally reviewed, agreed, and signed off by the stakeholders as is, for example, prescribed by the TOGAF framework [4].

Work packages may be triggered or interrupted by an implementation event. Also, work packages may raise events that trigger other behavior. Unlike a work package, an event is instantaneous: it does not have a duration.

An implementation event may have a time attribute that denotes the moment or moments at which the event happens. For example, this can be used to model project schedules and milestones; e.g., an event that triggers a work package, an event that denotes its completion (with a triggering relationship from the work package to the event), or an event that denotes a lifecycle change of a deliverable (via an access relationship to that deliverable).

Implementation events access deliverables to fulfill project objectives. For example, in a project to deliver a completely new application along with the technology needed to host it, an implementation event “release to production” could access the deliverables “final build”, “staging environment”, and “production environment”.

An implementation event may trigger or be triggered (raised) by a work package or a plateau. An implementation event may access a deliverable and may be composed of other implementation events.

An implementation event may be associated with any core element; e.g., to indicate a lifecycle state change. The name of an implementation event should preferably be a verb in the perfect tense; e.g., “project initiation phase completed”.

An important premise in the TOGAF framework is that the various architectures are described for different stages in time. In each of the Phases B, C, and D of the ADM, Baseline and Target Architecture descriptions are created, describing the current situation and the desired future situation. In Phase E (Opportunities and Solutions), so-called Transition Architectures are defined, showing the enterprise at incremental states reflecting periods of transition between the Baseline and Target Architectures. Transition Architectures are used to allow for individual work packages and projects to be grouped into managed portfolios and programs, illustrating the business value at each stage and expressing the step-by-step approach to migration.

In order to support this, the plateau element is defined.

The gap element is associated with two plateaus (e.g., Baseline and Target Architectures, or two consecutive Transition Architectures) and represents the differences between these plateaus.

In the TOGAF framework [4], a gap is an important outcome of a gap analysis in Phases B, C, and D of the ADM process, and forms an important input for the subsequent implementation and migration planning.