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Deployment Planning Guide > Siebel Architecture Overview > About SISNAPISiebel Internet Session Network API (SISNAPI) is a Siebel proprietary message-body format running on top of TCP/IP. SISNAPI communicates between the Web server, Siebel Gateway Name Server, and Siebel Servers. When a client request comes to the Web server, the Siebel Web Server Extension (SWSE) intercepts the request and forwards it in SISNAPI format. The SISNAPI message-body format has the following parts: HTTP HeaderWhen the Siebel Web Server Extension (SWSE) requests a new connection, the initial packets of the first SISNAPI message contain an HTTP header. This header includes a Uniform Resource Locator (URL) that provides routing information to the Siebel Enterprise Server, Siebel Server, and server component. Third-party HTTP load balancers use routing rules to parse the URL and route the message to the correct Siebel Server. Connection MultiplexingSISNAPI TCP/IP connections are specific to an Application Object Manager on one Siebel Server. Before opening new connections, the system checks to see if an existing connection is available. If so, the system uses the existing connection. Once the connection is established, it remains open for use by subsequent messages in the session or to be reused by other sessions. User Request TypesThe Siebel Web Server Extension (SWSE) generates three types of user requests. Each request causes a new connection to a Siebel Server through the load balancer: initial request, retry request, and reconnect request. The Siebel load balancing module in the SWSE recognizes these requests types and automatically routes them correctly. If you use a third-party HTTP load balancer, you must configure routing rules to handle these requests.
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Deployment Planning Guide |