About Siebel User Request Flow

Figure 2-2 illustrates how a user request is processed within the Siebel Business Applications architecture and infrastructure (generically presented), and shows potential areas for performance tuning. For a description of each portion of this data flow, see Siebel System Administration Guide and other relevant documents on the Siebel Bookshelf.

Figure 2-2 Generic User Request Flow in Siebel Business Application

A typical Siebel client request flows from the user's Siebel Web Client through the system, and back again, following the general flow outlined below.

1. A user performs an action that initiates a request. For example, the user clicks a link in the Site Map to navigate to a particular view. The request is generated by the Web browser and Siebel Web Client framework.

2. The request goes through the network, using a new or an existing HTTP connection, to the Siebel Application Interface. The request might go through a network router, proxy server, cache engine, or other mechanism.

3. The Siebel Application Interface receives the HTTP request and determines that it is a Siebel application request.

4. The Siebel Application Interface parses the HTTP message and generates a Siebel Internet Session Network Application Programming Interface (SISNAPI) message, based on the content of the HTTP message. Siebel Application Interface also parses the incoming cookie to obtain the user session ID.

   The Siebel Application Interface and Siebel Gateway work together to provide Siebel Server load balancing. When a user requests a new application connection, Siebel Application Interface sends a request to Siebel Gateway, which returns a connect string for the least-loaded Application Object Manager from among the Siebel Servers supporting that component. The user session will use this Application Object Manager.

   SISNAPI is a messaging format that runs on top of the TCP/IP protocol. It is used for network communication between Siebel Servers and Siebel Application Interface.

5. On the Siebel Server, the SCBroker component receives the initial request for a session and forwards it to a Siebel Application Object Manager process. Subsequent communication for the session does not use SCBroker. For more information, see "Siebel Application Object Manager Infrastructure" and related topics.

6. The Siebel Application Object Manager receives and processes the SISNAPI message sent from Siebel Application Interface.

   If a database query is needed to retrieve the information, the Siebel Application Object Manager formulates the SQL statement and sends the request to the Siebel database over a database connection. The database request goes through the database connection, using a protocol format that is specific to the database connector.

7. The database executes the SQL statement and returns data back to the Siebel Application Object Manager. The Siebel Application Object Manager forwards the message to the Siebel Application Interface that originated it.

8. The Siebel Application Interface receives the SISNAPI message, and translates it back to HTTP. The message is now in the form of Web page content.

9. The Siebel Application Interface load balancing configuration, if present, then forwards the Web page content through the original HTTP connection to the end user's Web browser.

10. The Web browser and the Siebel Web Client framework process and display the return message.