Converged Application Development James Steadman – Chief Solutions Architect

Scope SIP Servlets Converged applications Converged SIP and HTTP Servlet containers Convergence through decoupled containers

SIP Servlets “A SIP Servlet is a Java based application component that is managed by a container and performs SIP Signalling” –Rapid development and deployment –Provides industry accepted standardisation in SIP Application Development

SIP Servlets [2] SIP Servlets structure is derived from Java Servlets –Widely used proven model for developing web applications –Familiar to ISV development community javax.servlet.httpjavax.servlet.sipjavax.servlet

Converged Applications Converged applications –“A converged application is one that spans multiple protocols, for example, web, telephony, and presence.” Goal – support easier development of SIP applications that interact with other protocols. Click to Call

Comparison of SIP and HTTP Servlets Differences of SIP and Java Servlets –Java Servlets are synchronous –SIP Servlets are asynchronous –SIP Servlets provide proxying –SIP Servlets allow forking –SIP Servlets can behave as UACs Result of the divergence –Redundant HTTP methods and concepts remain in SIP servlet API

Converged Containers Spec suggests providing converged HTTP and SIP Servlet container. Issues with tightly coupled HTTP and SIP Servlet containers –HTTP and SIP Servlets have different behaviours –HTTP predominantly concerned with presentation –SIP is a session signalling protocol –Loss of flexibility to converge with other event sources/protocols.

Decoupled Containers Converged applications but decoupled containers. HTTP Servlet Container SIP Servlet Container EJB Container SIP HTTP RMI

Advantages and limitations of decoupling Advantages –Decoupling allows better design for the converged applications. –Exploits the ability for SIP Servlet applications to be converged with other event sources. Limitations –Needs evolution of development and deployment tools to ease the production of application. Already addressed in J2EE world.

Decoupled container progress Generic event framework concept proposed as an extension to the SIP Servlet specification. Draft APIs provided for review Concept still being developed and refined.

Summary SIP Servlets –A key development in the production of SIP enabled applications. Converged applications –A desirable and powerful concept Converged HTTP and SIP servlet container – A limited approach to achieving the aim of converged applications Converged application using decoupled containers. –Allows better converged application design and provides more flexibility and reusability