Web Service Architecture

     

A Web service is a software system identified by a URI, whose public interfaces are defined and described using XML. The other software systems can interact with these systems using XML messages. This definition closely matches the W3C Web service architecture group 's definition. ^[1] Figure 5.5 explains this architectural definition.

Figure 5.5. The Web service architecture.

The core information projected by Figure 5.5 includes:

• The Web service architecture is built around the XML technologies.

• The Web service is independent of the underlying transport mechanism.

• The messages exchanged between a customer and services forms the base layer of this architecture.

• These messages may be packaged and exchanged using envelopes including SOAP and its extension models.

• The SOAP extension models provide a number of SOAP header messages for message correlation, transactional capabilities, message reliability, and service addressing.

• There is a high-level description on the messages to exchange and the interaction pattern. This description can be given through any description language of choice. The most notable among these description languages are the Web Service Description Language, or simply WSDL.

• We can build a number of technologies around this architectural model. These technologies can be high-end applications, infrastructure software, and middleware solutions.

• Other notable features are the vertical pillars for security and management, which are needed for all the horizontal architecture components .

Now we will go through the details of these layers . We will start our discussion on the core technology builder, XML.