The scope of segment architecture3.1 The scope of segment is defined based on business need rather than architecture category
Many EA experts perceive segment architecture from the aspect of architecture convenience based on the same line of business. The article suggest that segment is defined based on the scope to close business performance gap. The scope of segment is defined to close the enterprise business performance gaps identified in the enterprise strategic plan rather than based architecture judgment to architect the similar category. Segment architecture is a continuous effort due to the nature of continuous strategic planning to identify the business weakness. The scope of segment defined based on business need may consist of many lines of business rather than based the architecture judgment in a “bird of the same feather” approach. It should not be confused with Line of Business Reference Architecture.
The depth of segment is defined based on business need rather than architecture category
Enable agile segment architecture by keeping it simple
the scope to just enough and the depth of segment is defined based on business need
3.2 Analogy to city planning
In the analogy of a city, Target architecture is similar to the city plan in a holistic but high level approach to lay out the overall enterprise plan based on the business mission and vision. a segment architecture is analogy to a city segment as shown in the green box in the following figure. A city is developed based on the demand of population and business need in a particular city segment. It is not developed based architecture convenience to build the entire road, all the school. In the same token, the segment architecture of an enterprise is also the area for enterprise business demand.
1.3 THE LOGICAL SEGMENT ARCHITECTURE
The logical segment architecture defined by Line of business.
1.4 The Scope of Segment
The physical segment is defined by the area.
Organic EA define the scope of segment architecture based on enterprise business performance gap. It is consider as a the enterprise weakness area rather than a line of business. A segment architecture can map to one and more line of business. It is not a one to one relationship. In addition to mapping the LOB, the scope of segment architecture also outline the weakness region in an enterprise for improvement. It is similar to specific area for improvement due to business and population growth. To improve a city, the city manager identify a segment of the city to plan for improvement. The city segment include many line of business in commercial, residential, transportation, education and infrastructure as shown in the following figure.
This is different from the segment define in the US Federal Segment Architecture Method. In the FSAM approach, a segment is considered as a synonymy to a LOB in a one-to-one mapping. Each segment is named after an LOB. It will be much more appropriate to name it as the LOB architecture to be more specific rather than segment architecture which cause significant confusion. A LOB is a category of business rather than the area of weakness. The selection of LOB for improvement is based on architecture judgment rather based business need. The FASM also advocate the LOB based segment architecture as a LOB reference architecture from the aspect of engineering to reuse. The Organic consider the segment architecture for the purpose to close business gap and clearly distinguish segment architecture from LOB reference for the engineering of reuse.
1.4 THE DEPTH OF SEGMENT ARCHITECTURE
Segment architecture is define a specific scope of Enterprise to close business performance gap. It elaborate the high level Enterprise Architecture within the segment scope. Enterprise Architecture is high level and notional alignment architecture which does not have the depth for transition planing. Segment Architecture is an alignment architecture in depth to support transition plan, performance based strategic planning, investment management and initiate projects for solution architecture. Architects must distinguish segment architecture from solution architecture to design the solution architecture blueprints. The following figure from the FSAM serve well to illustrate the relation between Enterprise Architecture, Segment Architecture and Solution Architecture.
4.1 Enterprise Architecture
The enterprise architecture is a high level enterprise master plan in the notion of "One EA". It is similar to a city plan with city development priciple. The enterprise architecture is the fundamental of the enterprise which do not subject to freqent change. For example: The city of Washington DC was planed hundreds years ago.
4.2 Segment Architecture
Segment architecture is a segment of Enterprise architecture with more detail architecture in the layer business, data, application and infrastructure. The scope of segment is defined to close the business performance gap from enterprise strategic planning. It is not defined bases on architecture judgment.
4.3 Solution architecture
Solution Architecture is technology oriented architecture design. It is very different from segment architecture.
5. The challenge of segment architecture
Segment architecture run the risk of segregation . EA is an aggregation effort, segment architecture is the divide and concur approach. The challenge of segment architecture is how to avoid segregation of creating stovepipe system during the segment architecture effort
5.1 Segment architecture align with the enterprise master plan.
5.2 Segment architecture comply with enterprise standards
6. The types of Segment
Segment architecture is a divide and conquer approach to accomplish the target architecture plan. identify architecture segment in the target architecture plan based on enterprise performance priorities via IT strategic planning.
Figure 2-3 illustrates the relationships between core mission areas, business services, and enterprise services with the agency. The relationships and dependencies between each segment type are defined and maintained by EA program staff in the agency EA transition strategy.