Section 15.2. Architecture


15.2. Architecture

The interactions among the parties are shown in the next three figures. Figure 15-1 illustrates the dealer-to-manufacturer relationship. Employees of the car dealer log on to the dealer's intranet using their browser, and then are authenticated with the system. From the car dealer page, they are able to access the manufacturer ordering site. When this happens, credentials for the dealer employee are communicated following a WS-Federation protocol to the manufacturer, which directly authenticates and grants access to its ordering systems to the dealer's employee.

Figure 15-1. Dealer-to-manufacturer interaction.


At this point, the Web servicesenabled browser can interact with the Web service that the car manufacturer provides for placing orders. The dealer's Web service retrieves and updates information from the customer database at the manufacturer. It ensures integrity of the messages exchanged by using WS-Security to sign messages sent by both parties. In Figure 15-1, wide arrows show Web servicesbased interactions. These include the WS-Federation taking place between authentication systems at the dealer and manufacturer sites and the interaction between the Web serviceenabled browser at the dealer and the ordering Web service at the manufacturer. Thin black arrows represent other interactions, such as traditional Web requests from a browser or database access to the manufacturer's customer database.

The interaction between the supplier and the manufacturer is shown in Figure 15-2. Once again, one can see how WS-Federation allows employees who are using the supplier applications to access the car manufacturer services by logging into the supplier systems. This is because both the supplier and manufacturer have federated their authentication systems. Based on their supplier agreement, the supplier can access the status of inventories at the manufacturer and order additional supplies when levels are low. A Web service provides access to the inventory systems. WS-Security protects the integrity and confidentiality of messages that are exchanged between the supplier Web service access application and the inventory service.

Figure 15-2. Supplier to manufacturer interaction.


Accessing the inventory system, the supplier employees detect low levels of a certain part. They place an order on behalf of the manufacturer into the supplier's ordering system. This interaction is shown in Figure 15-3. The request goes to the internal warehouse system, transmitted reliably using WS-ReliableMessaging to ensure exactly-once delivery of orders. This guarantees that orders are not lost because of network failure or because of the temporal unavailability of any of the systems involved. The warehouse system works with two warehouse subsystems at the two production sites that the supplier maintains.

Figure 15-3. Supplier warehouse services.


The company policy requires the two sites to divide the order in a certain way, so coordinated requests are sent to the warehouse systems at the two sites. To ensure that the complete order is fulfilled, the complete interaction is conducted transactionally using WS-AtomicTransactions. If one of the plants cannot provide the requested amount, both internal warehouse requests are cancelled, and the ordering application is informed of the error condition. The employee can then check inventories at the plants and, if needed, override the company policy to receive the supplies from whatever source is available.



    Web Services Platform Architecture(c) SOAP, WSDL, WS-Policy, WS-Addressing, WS-BP[.  .. ] More
    Web Services Platform Architecture(c) SOAP, WSDL, WS-Policy, WS-Addressing, WS-BP[. .. ] More
    ISBN: N/A
    EAN: N/A
    Year: 2005
    Pages: 176

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