P6 – Resource Sequence

The P6 Resource Sequence View provides a time-ordered examination of the interactions between Resource Types. These are usually depicted as event-trace diagrams and will have an accompanying description that defines the particular scenario or situation.

Concerns Addressed

  • Message Handling.
  • Complex System Behaviours.
  • Security Modelling.

Background

P6 views are valuable for moving to the next level of detail from the initial solution design, to help define a sequence of functions and Resource Interactions, and to ensure that each participating Resource or Port has the necessary information, at the right time, in order to perform its assigned functionality.

Usage

  • Analysis of resource events impacting operation.
  • Behavioural analysis.
  • Identification of non-functional system requirements.

Representation

  • Topological (connected shapes).
  • UML Sequence Diagram (preferred).

Detailed View Description

The P6 View specifies the sequence in which data elements are exchanged in context of a Resource Type or Port. Resource event / trace descriptions are sometimes called ‘sequence diagrams’, ‘event scenarios’ or ‘timing diagrams’. Figure 3-68 shows the components of a P6 view. The items across the top of the diagram are usages of Resource Type or Ports. The lifelines are depicted as vertical lines descending from the Resource Type and Ports.

Figure 3-68: Example P6 Resource Event-Trace Description

The P6 provides a time-ordered examination of the data elements exchanged between participating Resource Type or Ports, and the required time interval between exchanges may be shown as a measure between the arrows. Each event- trace diagram will have an accompanying description that defines the particular scenario or situation.

The content of exchanges that connect lifelines in a P6 view may be related, in modelling terms, with resource interactions (from the P2, Resource Structure), data flows (from the P4, Resource Functions, and P3, Resource Connectivity) and data schema entities (from the P7, Physical Data Model) modelled in other views.

The interactions in a P6 view are not just limited to representing information flows. As in P2 and P4, they may also represent flows of materiel, human resources or energy.

Key Elements and Their Relationships

Meta-Model

The detailed meta-model and element list for P6, Resource Sequence, is at paragraph 4.5.7.