SO FAR, WE HAVE EXPLORED THE CONCEPTS OF SERVICE-ORIENTED ARCHITECTURE AND EXAMINED THE organizational consequences of implementing SOA. However, in practice SOA is only one aspect of the overall architecture of a system landscape. SOA has to do with how systems communicate to perform distributed processes. Those distributed processes are initiated by frontends or batch processes and store their data in backends, and the way SOA organizes the communication has an impact on both the frontends and the backends.
This chapter will situate SOA in the context of the global picture of SOA-based system landscapes. We'll begin by examining different ways of modeling a SOA-based architecture. Then we'll discuss topics such as work sharing between SOA and frontends, and specific questions regarding connectivity to backends.
Diagrams of a SOA-based system landscape may look very different, depending on the illustrator's intentions and point of view. Such illustrations may focus on business, domain, logical, or technical aspects of the landscape.
An architecture model focusing on the business or logical aspects of a system landscape might look like Figure 9-1.
Figure 9-1. A logical SOA-based architecture model
Inside your landscape you have different domains, which play specific roles and have specific responsibilities. ...