Architecture Modelling utilising Architecture Trade Off Analysis ( ATAM)

There are many facets to managing the Enterprise Architecture Landscape. Organisational Change and business transformation is challenging.  Having alignment between business goals and the technical architecture is often difficult to quantify.

ATAM graphic

In order to successfully transforming the business from its baseline to target operating model then there is often more than one route to get there.  How can you explore the pros and cons of each option?  The Architecture Trade-off Analysis Method can help.

This technique helps you asses the various options against agreed criteria assisting you to objectively score each option.  The goals and business drivers help weight the criteria used – calibrating the criteria used to assess and trade off the pros and cons of each with business drivers.

At the start of the analysis and in order to establish if the ATAM method is appropriate for evaluating the web services the following assets are  analysed.

A suitable modelling framework, such as Zachman, ArchiMate, TOGAF or DODAF can be used to create the views required.  The framework selected must complement your organisation’s needs, ways of working and assets and can be tailored to align to your terminology by use of a glossary.


Architectural Approach

Typical artifacts resulting from an ATAM and presented are shown below


•    Scenarios and prioritisation
•    Utility tree
•    Risks discovered
•    Non risks documented
•    Sensitivity and trade-off points found


A visual example of the proposed criteria to score the 3 web services options:-

 

The trade-off analysis looks at each option against agreed scenarios to assess each option in detail –identifying the risks and sensitivities for each option.

 
If we take one of the criteria used to score the option – availability we can look at a scenario relating to availability that was used:-


If servers encounter hardware failures (power, hard drive) the system must still be available


A trade-off identified when analysing this scenario associated with the availability criteria is shown below:-


Trade-off1:-Increasing the number of client server relations internal to the system will help offset performance issues but will increase the cost of the system.


As the sensitivities, trade-offs and options are analysed in detail an objective scoring of each option can give a balanced view of the relative merits of each option prior to buying or detailed desig. Thus reducing the risk of unsuitable solutions being selected.

To use the ATAM method effectively a comprehensive look at each design, evaluation and agreement of criteria used is a prerequisite to its success. Then a candid evaluation  of each option by identifying relevant scenarios, where analysis of the options helps uncover sensitivities, risks and trade-offs result in an more informed decision making process for evaluating the options.


This article is only intended to introduce ATAM and is aimed at wanting you to learn more.

 




 

 

 

 


 

 


Benefits of Modelling


  • Ability to articulate strategic view of landscape Optimise data use
  • Reduce infrastructure duplication and optimise non-functional aspects
  • More effective decision making due to up front options analysis with simulation of key requirements
  • Ability to communicate conflicting goals and drivers and facilitate conflict resolution
  • Highlight misalignment of priorities
  • Show competing demands for business services allowing compromise service levels to be defined
  • Improve oversight and Architectural Governance

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