Concept: Lifecycle Architecture Milestone
This guideline discusses the evaluation criteria for the Lifecycle Architecture Milestone at the end of the elaboration phase. The state of the essential artifacts is also described.
Main Description

At the end of the elaboration phase is the second important project milestone, the Lifecycle Architecture Milestone. At this point, you examine the detailed system objectives and scope, the choice of architecture, and the resolution of the major risks.

Evaluation Criteria

  • The product Vision and requirements are stable.
  • The architecture is stable.
  • The key approaches to be used in test and evaluation are proven.
  • Test and evaluation of executable prototypes have demonstrated that the major risk elements have been addressed and have been credibly resolved.
  • The iteration plans for the construction phase are of sufficient detail and fidelity to allow the work to proceed.
  • The iteration plans for the construction phase are supported by credible estimates.
  • All stakeholders agree that the current vision can be met if the current plan is executed to develop the complete system, in the context of the current architecture.
  • Actual resource expenditure versus planned expenditure is acceptable.

The project may be aborted or considerably re-thought if it fails to reach this milestone.


Essential Artifacts (in order of importance) State at milestone
Prototypes One or more executable architectural prototypes have been created to explore critical functionality and architecturally significant scenarios. See the note below on the role of prototyping.
Risk List Updated and reviewed. New risks are likely to be architectural in nature, primarily relating to the handling of non-functional requirements.
Development Process

The development process, including any project-specific guidelines and templates, has been refined based on early project experience, and is sufficiently defined for the construction phase to proceed.

Development Infrastructure

The development environment for construction is in place, including all tools and automation support for the process.

Software Architecture Document Created and baselined, including detailed descriptions for the architecturally significant use cases (use-case view), identification of key mechanisms and design elements (logical view), plus definition of the process view and the deployment view (see Artifact: Deployment Model) if the system is distributed or must deal with concurrency issues.
Design Model (and all constituent artifacts) Defined and baselined. Design use-case realizations for architecturally significant scenarios have been defined and required behavior has been allocated to appropriate design elements. Components have been identified and the make/buy/reuse decisions sufficiently understood to determine the construction phase cost and schedule with confidence. The selected architectural components are integrated and assessed against the primary scenarios. Lessons learned from these activities may well result in a redesign of the architecture, taking into consideration alternative designs or reconsideration of the requirements.
Data Model Defined and baselined. Major data model elements (e.g. important entities, relationships, tables) defined and reviewed.
Implementation Model (and all constituent artifacts, including Implementation Elements) Initial structure created and major components prototyped.
Vision Refined, based on new information obtained during the phase, establishing a solid understanding of the most critical use cases that drive the architectural and planning decisions.
Software Development Plan Updated and expanded to cover the Construction and Transition phases.
Iteration Plan Iteration plan for the construction phase completed and reviewed.
Use-Case Model (Actors, Use Cases) A use-case model (approximately 80% complete)-all use cases having been identified in the use-case model survey, all actors having been identified, and most use-case descriptions (requirements capture) have been developed.
Supplementary Specifications Supplementary requirements capturing the non functional requirements are documented and reviewed.
Test Suite ("smoke test") Tests implemented and executed to validate the stability of the build for each executable releases created during the elaboration phase.
Test Automation Architecture A baselined composition of the various mechanisms and key software elements that embody the fundamental characteristics of the test automation software system.
Optional Artifacts State at milestone
Business Case Updated if architectural investigations uncover issues that change fundamental project assumptions.
Analysis Model May be developed as a formal artifact; frequently not formally maintained, evolving into an early version of the Design Model instead.
User Support Material User Manuals and other training materials. Preliminary draft, based on use cases.  May be needed if the system has a strong user interface aspect.

The Role of Prototyping

The Rational Unified Process gives the software architect and project manager the freedom to construct prototypes of several types (see Concept: Prototypes) as a risk reduction strategy. Some of these prototypes may be purely exploratory, and are subsequently discarded. However, it is likely (certainly for larger or unprecedented systems) that the architecture will have been constructed as a series of evolutionary prototypes-covering different issues as elaboration proceeds-and by the end of elaboration, will have culminated in an integrated, stable architectural base. We do not mean to suggest here that the prototyping effort during elaboration should result in a set of architectural fragments, which need not be integrated.