Few abbreviations connected with the future air traffic management systems have given rise to so many questions and misunderstandings as EA (Enterprise Architecture) and SOA (Service Oriented Architecture). In the United States both concepts are part and parcel of air traffic management system development since the marching orders were given by the Federal Government. In Europe, however, it was only during the SESAR development phase that EA and SOA were first introduced into the ATM context and the reception was at first mixed.
To-day there is probably no doubt any more that EA and SOA are the way to go but the fact remains: to many in the air traffic management family the exact meaning of both remains a puzzle.
Let's try to set out the pieces and see what picture emerges.
EA and SOA of non-aviation fame
Originally, the concepts of enterprise architecture and service orientation had nothing to do with air traffic management. They were defined and progressively refined to answer the needs of complex information technology (IT) systems with a view in particular to improving the business agility of those systems. EA and SOA aim to break the stranglehold of information technology on the business aspects of the enterprise, enabling business needs to drive IT rather then the other way round.
That EA and SOA are usable also in the air traffic management context is a tacit admission that ATM is not unique in its requirements and that under the skin ATM systems, all claims to the contrary, have a lot in common with other critical systems, like those controlling the power grids or enabling remotely controlled surgical operations. All those systems need to crunch prodigious amounts of real time data, must provide common situational awareness and are driven by decisions.
If EA and SOA can improve those systems, it stands to reason that they can also help in making air traffic management systems better even if certain adaptations of the original ideas may be required.
So what is Enterprise Architecture (EA)?
The definition of EA given by the Institute of Enterprise Architecture Development (IFEAD) is the following:
"Enterprise architecture is a complete expression of the enterprise; a master plan which" acts as a collaboration force "between aspects of business planning such as goals, visions, strategies and governance principles; aspects of business operations such as business terms, organization structures, processes and data; aspects of automation such as information systems and databases; and the enabling technological infrastructure of the business such as computers, operating systems and networks. "
Fine you will say … how does this help air traffic management? Critics often say that the architecture of the enterprise exists whether or not it is described. True, but we have seen what happens when lots of ATM enterprises grow without following an overall strategic guidance and then try to work together. That is called European ATM before SESAR …
In this view, the definition of EA from the MIT Center for Information Systems Research is particularly relevant:
"Enterprise architecture is the organizing logic for business processes and IT infrastructure reflecting the integration and standardization requirements of the firm's operating model."
We are getting nearer …
And EA in air traffic management?
The SESAR program is the European Air Traffic Management modernization program that combines technological, economic and regulatory aspects of ATM and which will use the Single European Sky (SES) legislation to synchronize the plans and actions of the different partners and federate resources for the development and implementation of the required improvements throughout Europe, in both airborne and ground systems.
Although SES does provide the legislative basis for implementing the future ATM system, it is still necessary to devise and agree an overall framework in which the hitherto fragmented elements of European ATM can be properly bundled and aligned towards the SESAR strategic goals. These goals imply in particular a net-centric, service oriented approach to air traffic management.
To achieve the goals, European ATM has to be seen as a single enterprise in which the constituent parts work together in a networked, service based operation, with the business processes driving the supporting IT infrastructure.
Once we recognize that air traffic management in Europe needs to be seen as a single enterprise (even if it is composed of several constituent entities), the aims and goals of the Enterprise Architecture concept suddenly become not only relevant but also a highly desirable solution.
A European ATM enterprise architecture?
To instantiate the single enterprise concept, we can define the European ATM Enterprise Architecture (EAEA), building upon the more generic idea of Enterprise Architecture (EA), however adapted both in scope and content to the air traffic management environment.
So what is the purpose of an EAEA?
EAEA can guide and focus the strategic decisions, in particular those related to the air traffic management operational concept implementation and supporting information technology investments. This enables the partners to proactively plan the introduction of services, avoid duplication of developments, reduce costs and better align IT investments to the business processes on all levels.
EAEA can also provide the strategic guidance for the efforts to define and implement, on both business and IT level, a Service Oriented Architecture (SOA) duly adapted to the requirements of the European ATM environment.
But what is the ATM enterprise?
A convenient definition of the European ATM enterprise could be the "totality of the partners in the SESAR Performance Partnership". Other definitions are possible, the important message being that every partner who needs to use ATM or has something to contribute must be seen as an element of the single, overall enterprise.
Using the above definitions, we can conclude that the European ATM Enterprise Architecture is the description of the structure and behavior of the partners' processes, information systems, personnel and organizational sub-units, aligned with the enterprise's performance goals and strategic directions as defined in the SESAR program.
And SOA then?
As will be clear by now, EAEA provides a business-driven framework that allows the description of the various parts of European ATM and their interactions from different points of view (including both operational and technical aspects). EAEA provides a meaningful way to partition and manage the complexity of the ATM environment, to reconcile different partners' business visions across the Single European ATM System and to create a bridge between the businesses and IT requirements.
SOA is an approach that uses the notion of "services" which can be used to populate the EAEA framework.
"Service" is a word that can mean different things depending upon the context in which it is being used. In general, the context is based upon a consumer / supplier relationship. Further, a hierarchy of services can exist with, for example, a high-level service being made up of a number of lower level sub-categories of services. Therefore, it is very important to ensure that the nature, scope and detailed characteristics associated with each service are clear and unambiguous each time it is used, including defining who is supplying what to whom.
Services may be defined from a business perspective or an IT perspective.
Services from the business perspective
A service from the business perspective is really the consumer's view of the provider's capabilities. The services must meet defined characteristics to ensure their efficiency and cost effectiveness. Among others, they must be modular and autonomous, delivered where needed, shareable and reusable and above all, they must drive the underlying IT support and not vice versa.
Services can be defined on several levels of the enterprise but in the air traffic management context, the operational services are the highest level of service. A service can be associated to one or more contracts, a service contract being understood as being an agreement (generally expressed as a Service-Level Agreement) between two or more parties.
Increasing competition, globalization and technology advances are driving airlines, airports and other users of ATM to change their products, business processes and prices more frequently than they did in the past. The structure of services offers the flexibility to adapt more quickly to fast-changing conditions.
SESAR has promoted the vision of creating a performance partnership structure which links the Airspace Users, Airport Operators and ANSPs as the way in which the future ATM System will be defined, created, implemented, delivered and managed. The notion of the supply and consumption of operational services through a set of Service Level Agreements will be the way in which the partners will be bound together from a business perspective but retaining the flexibility afforded by service orientation to be able to efficiently react to changing circumstances and demands.
While the word "business" and air traffic management have not often been used together in the past, it needs to be recognized that the constantly evolving business world of the airspace users must be served by an air traffic management system that is able to evolve with it and remain safe and cost efficient at the same time. This essential business agility can best be achieved by service orientation.
Services from the IT perspective
From an information technology (IT) perspective, the use of services defines IT services that correspond to real-world business activities or recognizable business functions and that can be accessed according to the service policies that have been established for the business services relationships. In addition to the IT services that are directly supporting the business services, technical services can be defined that can be re-used across the enterprise, providing generic technical functions (data transformation, logging, identification management, etc.). There are many different ways to describe such services depending upon the way in which the interactions between the IT systems are needed to facilitate and enable the business view.
From the specific air traffic management point of view, the highest priority is to define the business services as these will drive the services to be developed in the IT context.
EA and SOA in NextGen?
Yes, absolutely. The use of enterprise architecture methods and service orientation has been mandated for all federal projects and so NextGen is being developed on this basis. This is a major advantage compared to Europe where no doubt a lot of discussion will still need to go on before agreement can be reached between all partners on the finer details of enterprise architecture and service orientation.
Do we understand EA and SOA now?
I guess this write-up is probably too simplistic for the experts and possibly still too abstract for the average person involved in air traffic management. Logical as EA and SOA is they need a shift in thinking and the acceptance of a few things we do not readily conclude otherwise.
I will try to summarise the most salient points here, may be that will help. If you still have a question, leave a comment and we will come back on the issue you raise.
o EA and SOA are not air traffic management construct but they are applicable to ATM systems also. ATM systems are not unique.
o While safety is always paramount, air traffic management serves a major worldwide business community and hence ATM must have the required business agility to be able to adapt to the changing business environment.
o The ATM "enterprise" needs an overall guiding framework to enable coordinated and focused development.
o Business requirements must drive information technology and not the other way around.
o Enterprise Architecture (EA) provides the required guiding framework; Service Oriented Architecture within it provides the structure ensuring a business (as opposed to IT) driven system.
o Both SESAR and NextGen will use EA and SOA.
Note: The use of some text from the SOA TF, of which I was a member, is gratefully acknowledged.