HP-UX Java SIP Stack Programmer's Guide (February 2008)

2 JSR32 JAIN SIP APIs
This chapter discusses the JSR32 stack architecture, the main objects in the stack, the
packages and factories available in the stack, and the JSR32 features.
This chapter addresses the following topics:
• “Overview”
• “JSR32 Architecture” (page 36)
• “HP-UX JSR32 Features” (page 42)
Overview
The SIP protocol, as defined in RFC 3261 (Session Initiation Protocol), is accepted as the
industry standard for establishing sessions between users in a network. In a
heterogeneous network, applications on different types of stacks must interact with
each other for exchanging or passing information. Though the SIP protocol specification
ensures interoperability between different stacks, it does not address interoperability
between applications in different types of stacks. JAIN SIP (JSIP) fulfils this requirement
by using the Java programming language to define an API specification that ensures
interoperability between stacks and also interoperability of applications across stacks.
The Java APIs for Integrated Networks (JAIN) is an activity within the Java Community
Process (JCP), that develops APIs for telephony (voice and data) services. JSR32, the
JSIP API specification, defines APIs that enable rapid development of IP telephony
services and applications using Java. The JSIP APIs provide a standard portable interface
to share information between SIP clients and SIP servers, through call control elements
and by enabling converged-network applications. These APIs enable application
developers to have powerful access to the SIP protocol.
JSIP offers the following benefits:
• Standardizes the interface to the stack.
• Standardizes the message interface.
• Standardizes events and event semantics
• Provides application portability that enables interoperability of applications across
stacks.
The JSIP supports the SIP protocol described in RFC 3261. It can be used in a user agent,
proxy server, redirect server, or registrar.
JSIP APIs provide the following functions:
• Provide methods to format SIP messages.
• Enable an application to send and receive SIP messages.
• Parse incoming messages.
• Enable applications to access fields through a standardized Java interface.
Overview 35