1. Developer Guide
  2. Composing SIP Applications
  3. Session Key-Based Request Targeting

Session Key-Based Request Targeting

The SIP Servlet v2.0 specification provides a mechanism for associating an initial request with an existing SipApplicationSession object. This mechanism is called session key-based targeting. Session key-based targeting is used to direct initial requests having a particular subscriber (request URI) or region, or other feature to an already-existing SipApplicationSession, rather than generating a new session.

Accessing SIP Applications Using SIP Application Index Keys

To use this targeting mechanism with an application, you create a method that generates a unique key and annotate that method with @SipApplicationKey. When the SIP container selects that application (for example, as a result of the AR choosing it for an initial request), it obtains a key using the annotated method, and uses the key and application name to determine if the SipApplicationSession exists. If one exists, the container associates the new request with the existing session, rather than generating a new session.

Note:

If you develop a spiral proxy application using this targeting mechanism, and the application modifies the record-route more than once, it must generate different keys for the initial request, if necessary, when processing record-route hops. If it does not, then the application cannot discriminate record-route hops for subsequent requests.

See section 18-30 in the SIP Servlet Specification v2.0 (http://jcp.org/en/jsr/detail?id=359) for more information about using session key-based targeting.

Application Composition and SIP-HTTP Convergence

The @SipApplicationKey annotation is a useful tool you can employ to process HTTP requests in a converged module. You can set up a JavaServer page to manage the call states of a SIP application, an HTTP servlet to process HTTP requests and a proxy application to proxy the call request to more than one user agent server (UAS).

Converged Application Server provides an example called convergence_indexkey that shows how SIP application session index keys can be used to access SIP applications. It uses application composition whereby more than one application is called to process the same SIP request; and also shows SIP-HTTP session convergence.

The convergence_indexkey example employs the JSR 289 API interfaces called javax.servlet.sip.ConvergedHttpSession and javax.servlet.sip.SipSessionsUtil. The example is packaged as an exploded EAR file containing a web application and the Enterprise Java Beans (EJB).

Note:

The web application and EJB access do not require the configuration file sip.xml.

For more information about accessing convergence_indexkey, see "Examples".