SPA2005 session: SOA: Are You Being Served? What is a Service Oriented Architecture? How and why do you do build one?

One-line description:This session explores the characteristics of a “service oriented architecture” (SOA) and examines definitions, applicability, benefits and practical issues through case study exercises
 
Session format: Workshop [read about the different session types]
 
Abstract:SOA is the latest system-structuring paradigm to be foisted on software architects. At present, it is difficult to read a contemporary software industry periodical or web site without reading about the benefits of the SOA approach.

There is a growing body of opinion that SOA based document/process oriented applications are more flexible, for example see http://www.ftponline.com/ea/magazine/fall/online/avernet/default_pf.aspx . But there is also still much debate on how this fits with existing application development techniques and the wider issue of whether SOA represents a universal new architectural paradigm, for example see http://www.cbronline.com/content/COMP/Magazine/Articles/Features/ServiceatYourDiscretion.asp .

So what is a “service”, what is a “service oriented architecture”, and why should we be interested using them? This workshop will allow its participants to analyse the service-oriented approach to system development, both in the abstract and via concrete exercises.

 
Audience background:Architects, designers, developers and managers involved in the development of distributed systems.
 
Benefits of participating:* An appreciation of the issues in pinning down the definition of “service” as it used in the context of SOA.
* An appreciation of some of the issues of designing an SOA architecture that leverages the data and functionality of existing systems.
* An opportunity to share experiences on how widely applicable the SOA approach really is, and whether expectations of benefits are realistic.
 
Materials provided:* Presentation slides.
* Example system for deciding on a set of services (Exercise 1).
* Example service structure as a basis for defining service interfaces (Exercise 2).
 
Process:1. Introductory presentation, providing background on the concepts of SOA and providing the presenters’ views of what a service is and the benefits that may, or may not, be obtained. A bit on technology – at least sufficient to differentiate SOA from Web Services.
2. Presentation: Doing SOA. Examine SOA as a way of thinking about the relationship between business and IT structures.
3. Divide the participants into groups for exercises.
4. Exercise 1: SOA or not SOA? The groups are given views of an existing enterprise with a “traditional” architecture. Participants work in their groups to define a suitable service structure, and propose what the benefits of restructuring to a service based architecture might be.
5. Group Presentations: Each group presents their conclusions about whether their system seems suited to SOA, what the services might and the potential benefits.
6. Exercise 2: It’s the Business. The groups build on the service definitions by defining service interfaces and show how the services support a business scenario.
7. Group Presentations: the groups show how their services support the business scenario. Issues and thoughts are collected by presenters as the presentations are given.
8. Wrap-up: review of collated thoughts from second set of presentations.

00:00 – 00:10 Introductions
00:10 – 00:30 Presentation: What is SOA?
00:30 – 00:50 Presentation: Doing SOA
00:50 – 01:20 Exercise 1
01:20 – 01:35 Presentations and Discussion
01:35 – 01:50 Break
01:50 – 02:20 Exercise 2
02:20 – 02:35 Presentations and Discussion
02:35 – 02:45 Conclusions and Wrap up

 
Outputs:* Alternative definitions of “service” in the SOA context.
* Collated views and comments on the benefits that may or may not be obtained from SOA.
* A set of principles to guide the use of services as a system structuring mechanism.
* Collated experiences and ideas on how to build an SOA that re-uses legacy assets.
The outputs will be presented as posters at the event, with summaries written up for the SPA2005 Outputs Wiki.
 
History:We've not presented this material before. However, we did do a session that used a similar format quite successfully last year: http://www.spa2005.org/cgi-bin/wiki.pl/ot2004/?KkbagdccfbejcacheglutnserverntlinetKk.
 
Presenters
1. Eoin Woods
Zuhlke Engineering Ltd
2. Andy Longshaw
Blue Skyline
3. Ashley McNeile
Metamaxim Ltd.