Saturday 27 October 2012

Enterprise architecture methodology



EA Methodology
Implementation methodology is a key element of Enterprise Architecture (EA) program. EA methodology is a detailed description of how the EA program is to be established and run, and how the documentation of the EA is to be developed, maintained, and used.
The purpose of an EA methodology within the EA program:
-          EA methodology is a detailed procedure for establishing, maintaining and using an EA framework and documentation approach.
-          It is the first step in coordinating the EA documentation approach.
-          Adopting it reduces the risk of creating an ineffective EA program and/or inaccurate EA documentation.
EA Methodology Comparison
With different kinds of EA frameworks, EA methodologies are very different respectively in their approaches. However, it is hard to know which one is best EA methodology. Each kind has advantages and disadvantages, so choosing what kind of them is depending on each organization. There are twelve criteria that are most often used for comparing and evaluating enterprise-architectural methodologies. Not all of these criteria might have a connection with your organization, and some might be more important than others. But, basing on them, IT specialists can evaluate and choose suitable kinds of EA methodologies applied their organization. There are some ways to rank each methodology in each criteria. For examples, the ratings will be assigned as follows:
-          1: Does a very poor job in this section
-          2: Does an inadequate job in this section
-          3: Does an acceptable job in this section
-          4: Does a very good job in this section
The criteria and ratings are summarized in the table below:

Ratings
Criteria
Zachman
TOGAF
FEA
Gartner
Taxonomy completeness
4
2
2
1
Process completeness
1
4
2
3
Reference-model guidance
1
3
4
1
Practice guidance
1
2
2
4
Maturity model
1
1
3
2
Business focus
1
2
1
4
Governance guidance
1
2
3
3
Partitioning guidance
1
2
4
3
Prescriptive catalog
1
2
4
2
Vendor neutrality
2
4
3
1
Information availability
2
4
2
1
Time to value
1
3
1
4
Table. Criteria and ratings for each methodology

The table above shows that none of the enterprise-architecture methodologies is really complete. Each has its strengths and weaknesses.
In order to choose an appropriate methodology, companies can follow these steps:
  1. Go through the rows (criteria) in the table, eliminating any that they feel are not important to their organization.
  2. Add any additional rows (criteria) that are important to them, and rate each of the methodologies in that area.
  3. Change any of ratings above with which they disagree.
At the end of this task, they should have a good idea about the strengths and weaknesses of each methodology with respect to their enterprise's needs, then decide a suitable methodology. It is also important to find an EA consultant who specializes in helping enterprises implement that methodology.
For many organizations, the best choice is all of these methodologies, blended together in a way that works well within that organization's constraints. With that way, they create their own enterprise-architectural methodology consisting of bits and pieces of each of the methodologies that provide the highest value in their specific areas of concern.

References:
http://msdn.microsoft.com/en-us/library/bb466232.aspx
Lecture note – Week 6

Wednesday 3 October 2012

EA Frameworks

An enterprise architecture framework (EA framework) defines how to organize the structure and views related to an enterprise architecture.

There are three components which are views, methods and training or experience in the enterprise architecture framework. Views provide the mechanisms for communicating information about the relationships that are important in the architecture. Methods provide the discipline to gather and organize the data and construct the views in a way that helps ensure integrity, accuracy and completeness; training/experience : support the application of method and use of tools.

Enterprise architecture frameworks are important for companies, especially, large companies and architecture frameworks are commonly used in IT and information system governance because some reasons. Firstly, the discipline of enterprise engineering and enterprise architecture is so broad, and enterprises can be large and complex, the models associated with the discipline also tend to be large and complex. Secondly, there is a complexity of information system commonly that leads to failure in IT adoption of enterprises. To manage the scope of EA and complexity of IS, an architecture framework provides tools and methods that can bring the task into focus and allow valuable artifacts to be produced when they are most needed. The framework helps companies save a lot of effort and costs since it leaves the architect focus on own Enterprise issues. It leads the EA to development predictably and repeatably.

There are several popular types of EA frameworks. Firstly, the Zachman framework is actually more accurately defined as a taxonomy. Secondly, the Open Group Architectural Framework (TOGAF) is actually more accurately defined as a process. Thirdly, the Federal Enterprise Architecture can be viewed as either an implemented enterprise architecture or a proscriptive methodology for creating an enterprise architecture. Lastly, the Gartner Methodology can be best described as an enterprise architectural practice.


Refrences
Lecture notes – Week 5