System Architecting

Definition

System architecting is the subclass of architecting during which an application’s overall system architecture is produced.

Goals

The goals of system architecting are to:

• Produce and maintain the top-level strategic structure of an application including:
  • Determine the system's architectural style.
  • Produce the system's logical architecture.
  • Produce the system's physical architecture.

Objectives

The objectives of system architecting are to:

• Produce a formally documented consensus amoung the project stakeholdlers (e.g., client, management, developers) concerning the overall structure and major mechanisms of the next version [incremental iteration] of a system application.
• Provide input (e.g., number, size, and complexity of system components) to the project cost and schedule estimation task.
• Provide a basis (e.g., components) for the scheduling of the project phases and builds.
• Maximize the quality of the architecture:
  • Correctness, completeness, consistency, and understandability.
  • To meet architecturally significant:
    • Operational requirements,
    • Quality requirements (e.g., extensibility, scalability, performance, operational availability, and security),
    • Design constraints (e.g., use of existing databases), and
    • Business rules.
• Maximize the productivity of the architecture team (e.g., reuse of reusable architectural frameworks, reuse of architecture conventions, and existence of example documents).

Examples

Examples of system architecting include:

• TBD

Preconditions

Architecting typically may begin when the following preconditions hold:

• The initiation phase has started.
• The architecture team is initially staffed and adequately trained in system architecting.
• Some architecturally significant requirements have been specified.

Completion Criteria

Architecting is typically complete when the following postconditions hold:

• The system architecture has been documented.
• The deliverable work products in the architecture work product set have:
  • Passed evaluation.
  • Been accepted by the customer.
  • Been delivered to the customer.

Tasks

Architecting typically involves the following producers performing the following architecting tasks:

• Architecture Team, which performs:
  • Architecture Reuse
  • Architecture Prototyping
  • Architecture Documentation
  • Architecture Integrity Assurance

Environments

Architecting is typically performed using the following environment(s) and associated tools:

• Development Environments:
  • Whiteboards
  • Word processing tool
  • Modeling tools

Work Products

Architecting typically results in the production of part or all of the following architecture works:

• System Architecture Document

Phases

Architecting tasks are typically performed during the following phases:

• Initiation: Started
• Construction: Completed
• Delivery: Maintained
• Usage: Maintained
• Retirement: Not Applicable

Guidelines

• The system architecture must fulfill (and is therefore validated against) the architecturally significant operational and quality requirements.
• The system architecture drives and constrains the tactical (i.e., detailed) design.
• This activity is documented using the typical configuration for large projects. It is intended to be configured (i.e., instantiated, extended, and tailored) to meet the needs of specific projects.
• The preconditions of this activity should be the union of the preconditions of its constituent tasks.
• The completion criteria for this activity should be the union of the postconditions of its constituent tasks.