ATAM Architecture Tradeoff Analysis Method

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ATAMArchitecture Tradeoff Analysis Method

• Harish Chanda
• CS 644
• 10/28/08

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Agenda

• ATAM overview
• ATAM steps

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ATAM - Vocabulary

• Scenario A scenario is a short statement
  describing an interaction of one of the
  stakeholders with the system
• Stakeholder An individual, team, or
  organization (or classes thereof) with interests
  in, or concerns relative to, a system
• Functional requirements - specify what software
  has to do.
• Non-functional requirements specify how well it
  should be done.

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Whats ATAM

• Purpose To assess the consequences of
  architectural decisions in light of quality
  attribute requirements.

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ATAM Benefits

• Benefit
• Financial saves money
• Forces preparation / documentation /
  understanding
• Catch architectural errors before built
• Make sure architecture meets Requirements
• Reduces risk

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Participants

• Evaluation team (3-5)
• competent, unbiased outsiders
• Decision makers (?)
• Architect
• Project manager
• Customer
• Stakeholders (12-15)
• Developers / testers
• Users
• Developers on related projects

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Out puts of ATAM

• A concise presentation of the architecture
• Articulation of the business goals
• Quality requirements in terms of a collection of
  scenarios
• A set of risks and non-risks
• A set of risk themes

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Process Phases

• 0. Preparation - select participants, plan
  logistics
• 1. Evaluation - 1 day meeting
• (hiatus of 3 weeks)
• 2. Evaluation (continued) - 2 day meeting
• 3. Follow-up - 1 week reflection and report

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Process Steps

• Step 1 Present the ATAM
• Step 2 Present Business Drivers
• Step 3 Present Architecture
• Step 4 Identify Architectural Approaches
• Step 5 Generate Quality Attribute Utility Tree
• Step 6 Analyze Architectural Approaches
• (Hiatus)
• Step 7 Brainstorm and Prioritize Scenarios
• Step 8 Analyze Architectural Approaches
• Step 9 Present Results

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Step 1 Present the ATAM

• Evaluation leader explains the ATAM process

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Step 2 Present Business Drivers

• Project manager describes
• most important functions
• technical, managerial, economic or political
  constraints
• business goals and context
• major stakeholders
• major architectural drivers

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Step 3 Present Architecture

• Lead architect presents the architecture
• context diagram
• module or layer view
• component and connector view deployment view

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Step 4 Identify Architectural Approaches

• Evaluation team catalogs the patterns and
  approaches used

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Step 5 Generate Quality Attribute Utility Tree

• Quality attribute
• refinements
• scenarios
• Security

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Step 5 Utility Tree /cont.
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Step 6 Analyze Architectural Approaches

• Evaluation team examines highest-ranked scenarios
  for sensitivities, tradeoffs, risks and nonrisks

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Hiatus

• After 3 weeks restart evaluation with a larger
  team
• Recap results of first 6 steps at beginning of
  meeting

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Step 7 Brainstorm and Prioritize Scenarios

• Participants brainstorm scenarios appropriate to
  their roles (performance, maintenance, etc.)
• Scenarios are merged and ranked by voting

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Step 8 Analyze Architectural Approaches

• Architect explains how each scenario is realized
  by architectural approaches

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Step 9 Present Results

• Outputs are reported
• Risk themes are described