SIP
Servlet (JSR-116), developed through the Java
Community Process, is an open standard API that describes server-side
component interfaces for application development. Derived from the
popular Java Servlet architecture of J2EE, it brings Internet application
development capabilities to the building of SIP solutions.
In the component-container architecture defined by SIP Servlet,
a SIP application is a component that runs inside and is managed
by the Servlet container or application server. By leveraging the
services provided by the container, SIP application developers only
need to handle high-level business logic, thus simplifying their
work significantly.
The heart of the application server is the SIP protocol stack. The
server marshals and unmarshals SIP messages, manages SIP dialogs
and transactions, and implements the core SIP semantics. The server
then calls the application upon receiving an incoming message. The
application, in turn, calls the server to send an outgoing message.
In addition, SIP A/S also provides the following useful services:
- Application lifecycle management: the server manages the application¡¯s
lifecycle, through stages such as configuration, deployment, loading,
start, and shutdown.
- Resource management: the server manages resources, such as
threads, transports, memory, and timer
- Security service: the server offers transport and message level
security functions.
- many servers offer features such as clustering and failover
for high demand situations.
- Integration: the server can run both SIP applications and Web
applications. This provides easy integration for applications
such as a web-based telephone. The server also provides additional
unified access points to other applications through the Java Naming
and Directory Interface.
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