Sunday, August 12, 2012

At least three views of business architecture (TOGAF)

#entarch #bizarch #viewpoints In a previous post, I looked at the five viewpoints of business architecture according to the OMG. In this post, I shall look at the architectural modelling viewpoints indicated in TOGAF 9.1. (Section 8.2). In TOGAF, these viewpoints are presented more as suggestions rather than as a recommended set.

1. Hierarchical Activity Models (also called Business Process Models) Functions, data/information exchanges, activities, inputs, controls, outputs, mechanisms/resources, business rules General
2. Use Case Models Business processes, system functions, use case, actor, General
3. Business Class Models Information (entities and implementation classes, attributes and relationships), information behaviours General
4. Node Connectivity Diagram Nodes (role, org unit, location, facility), information transfer/flow Defence sector
5. Information Exchange Matrix Information Exchange Defence sector
6. Resource-Event-Agent Model Resources (goods, services or money), Event (transactions and agreements), Agent (people and organizations) Accounting domain

According to TOGAF, "a variety of modeling tools and techniques may be employed, if deemed appropriate". Items 1-3 are offered as general examples.

Items 4 and 5 are described as follows. "Although originally developed for use in the Defense sector, these models are finding increasing use in other sectors of government, and may also be considered for use in non-government environments."

Item 6 is included in a list of "business models relevant to common high-level business domains". Whereas the other members of the list are specific industry models, the Resource-Event-Agent (REA) Model appears to be a modelling viewpoint - indeed Wikipedia calls it an ontology. TOGAF asserts that the REA model "has proved so useful for better understanding of business processes that it has become one of the major modeling frameworks for both traditional enterprises and e-Commerce systems", but this assertion is contradicted by Wikipedia which suggests that its main influence has been in the classroom and in the development of such standards as ebXML.

Wikipedia: Resources, events, agents (accounting model)

TOGAF's set of viewpoints strongly emphasizes the information processing and information exchange elements of business architecture, while neglecting a number of other elements that are included in the OMG five viewpoints or my own six viewpoints

TOGAF lists a number of additional outputs from the business architecture work, which go beyond the modelling viewpoints it has specified.  These are 

Catalogs Organization/Actor catalog, Driver/Goal/Objective catalog, Role catalog, Business Service/Function catalog, Location catalog, Process/Event/Control/Product catalog, Contract/Measure catalog
Business Interaction matrix, Actor/Role matrix
Business Footprint diagram, Business Service/Information diagram, Functional Decomposition diagram, Product Lifecycle diagram, Goal/Objective/Service diagram, Use-case diagram, Organization Decomposition diagram, Process Flow diagram, Event diagram

Finally, TOGAF includes Business Scenarios, but I think this probably counts more as a requirements gathering technique than an architectural viewpoint.

I should welcome comments, especially from people who are familiar with TOGAF in practice.

1 comment:

Ron Segal said...

Richard, actually just a quick comment on Business Scenarios.
They do indeed seem to be expressed in 9.1 as a solution requirements 'tool' (including technology requirements), which is at odds with the statement regarding their particular relevance in the initial Visioning phase.

In this phase it does make sense to work through a series of Business Scenarios to help identify key business capabilities, however the 9.1 description of Business Scenarios would need to be changed to fit this kind of top down use, and is in my view misleading as it stands.

Best wishes