9.1 Interoperability
Key Takeaways
- TOGAF's first definition of interoperability is the ability to share information and services.
- Interoperability is commonly categorized as Operational or Business Interoperability, Information Interoperability, and Technical Interoperability.
- TOGAF's example degrees of interoperability run from Degree 1 Unstructured Data Exchange to Degree 4 Seamless Sharing of Information.
- The nature and security considerations of information and service exchanges are first revealed within business scenarios in Phase A.
- Phase E consolidates and reconciles interoperability requirements with potential solutions, and Phase F logically implements interoperability.
9.1 Interoperability
The Foundation syllabus asks you to briefly explain interoperability and how it is used. Defining the degree to which information and services are, or are not, to be shared is a very useful architectural requirement, especially in a complex organization or extended enterprise.
Definitions
The TOGAF Standard gives three definitions of interoperability:
- The ability to share information and services
- The ability of two or more systems or components to exchange and use information
- The ability of systems to provide and receive services from other systems and to use the services so interchanged to enable them to operate effectively together
There are many ways to define interoperability. The aim is to define one that is consistently applied within the enterprise and the extended enterprise — ideally, both use the same definitions.
Categories of Interoperability
Many organizations find it useful to categorize interoperability as follows:
| Category | What it defines |
|---|---|
| Operational or Business Interoperability | How different parts of the enterprise work together at the business level — how business processes are to be shared |
| Information Interoperability | How information is to be shared |
| Technical Interoperability | How technical resources are to be shared, or at least connect to one another |
From an IT perspective, TOGAF also suggests considering interoperability in a similar vein to Enterprise Application Integration (EAI):
| EAI-style view | Description |
|---|---|
| Presentation Integration/Interoperability | A common look-and-feel approach, through a common portal-like solution, guides the user to the underlying functionality of a set of systems |
| Information Integration/Interoperability | Corporate information is seamlessly shared between applications, normally based on a commonly accepted corporate ontology and shared services for structure, quality, access, and security/privacy |
| Application Integration/Interoperability | Corporate functionality is integrated and shareable so applications are not duplicated (for example, one change-of-address service rather than one per application) and are linked through functionality such as workflow |
| Technical Integration/Interoperability | Common methods and shared services for communication, storage, processing, and access to data, primarily in the application platform and communications infrastructure domains |
Degrees of Interoperability
TOGAF illustrates how interoperability can be expressed in degrees, using an example scheme from the Canadian government:
| Degree | Name | Description |
|---|---|---|
| 1 | Unstructured Data Exchange | Exchange of human-interpretable unstructured data, such as the free text found in operational estimates, analysis, and papers |
| 2 | Structured Data Exchange | Exchange of human-interpretable structured data intended for manual and/or automated handling, but requiring manual compilation, receipt, and/or message dispatch |
| 3 | Seamless Sharing of Data | Automated sharing of data among systems based on a common exchange model |
| 4 | Seamless Sharing of Information | An extension of degree 3 to the universal interpretation of information through data processing based on co-operating applications |
These degrees can be refined further for a specific enterprise — for example, dividing Seamless Sharing of Data into formal message exchange, common data exchange, complete data exchange, and real-time data exchange.
How Interoperability Is Used Across the ADM
The determination of interoperability is present throughout the ADM:
| ADM phase | Interoperability activity |
|---|---|
| Phase A: Architecture Vision | The nature and security considerations of information and service exchanges are first revealed within the business scenarios |
| Phase B: Business Architecture | Information and service exchanges are further defined in business terms |
| Phase C: Data Architecture | The content of information exchanges is detailed using the corporate data and/or information exchange model |
| Phase C: Application Architecture | The way applications are to share information and services is specified |
| Phase D: Technology Architecture | The appropriate technical mechanisms to permit the exchanges are specified |
| Phase E: Opportunities & Solutions | The actual solutions (for example, COTS packages) are selected; the step "Consolidate and Reconcile Interoperability Requirements" is performed |
| Phase F: Migration Planning | Interoperability is logically implemented |
Determining and Reconciling Interoperability Requirements
TOGAF recommends refining interoperability in the context of the enterprise operating model and then recording requirements in matrices, for example:
- A Business Information Interoperability Matrix showing which business stakeholders need to share which information, and at what degree
- An Information Systems Interoperability Matrix showing which systems must exchange information with which others, and at what degree
In Phase E, these requirements are reconciled with potential solutions. If a candidate COTS product cannot achieve the required degree of interoperability, the architect must either change the solution, change the requirement, or plan how to close the gap.
Scenario: Merging Two Hospital Networks
Two hospital groups merge. Clinicians need shared patient allergy information at Degree 4 (seamless sharing of information that both sides interpret identically), while monthly management reports only need Degree 2 (structured data compiled manually). The Business Information Interoperability Matrix captures these needs. In Phase C the architects define a common allergy data model; in Phase D they specify the exchange mechanisms; in Phase E they discover that one group's record system supports only file transfers, so a reconciliation decision is taken to add an integration service before the merged clinical workflow goes live.
Common Exam Pitfalls
- Treating interoperability as purely technical. TOGAF includes operational/business and information interoperability as well as technical.
- Scrambling the degrees. Degree 1 is unstructured data exchange; degree 4 is seamless sharing of information.
- Thinking interoperability belongs only to Phase D. It is revealed in Phase A and addressed in every phase through Phase F.
- Skipping reconciliation. Phase E consolidates and reconciles interoperability requirements with potential solutions.
Which category of interoperability defines how different parts of the enterprise work together at the business level?
In TOGAF's example degrees of interoperability, what is Degree 3?
In which ADM phase are the nature and security considerations of information and service exchanges first revealed, within the business scenarios?
A single change-of-address component is shared by all applications instead of each application having its own. Which EAI-style interoperability view does this illustrate?