ccessing their fields, transport of control information generated at © 2009 by Taylor & Francis Group, LLC SIP: Advanced Media Integration a meeting (RFC 2976), and instant messaging (RFC 3428). Other RFCs that complement the SIP specification are RFC 3262, 3265, 3311, 3326, and 3515. Jain SLEE [13] is the Java standard for Service Logic Execution Environ- ment (SLEE). SLEE is defined as runtime services with low latency, high performance and asynchronous event oriented; i.e., basic telecommunication services characteristics. Jain/Java Call Control (JCC) [13] is a specification (JSR 21) that abstracts the creation of VoIP services from the underlying protocol. It supports dif- ferent signaling protocols such as SIP, SS7, H.323 or MGCP. Its operation philosophy is based on subscription to the receipt of different events associ- ated with the following network roles. The SIP Servlet API is a specification of the Java community that defines a high-level API for SIP servers, enabling SIP applications to be deployed and managed based on the well-known HTTP Servlet model. SIP Servlets achieve their highest potential when they can be deployed along with HTTP Servlets in the same Application Server (also known as Servlet Container). This environment, which combines SIP and HTTP, truly realizes the power of converged voice/data networks. The HTTP protocol represents one of the most powerful data transmission protocols used in modern networks (think of the SOAP Web-services protocol). At the same time, SIP is the protocol of choice in most modern and future voice over IP (VoIP) networks for the signaling part. Therefore an Application Server capable of combining and leveraging the power of these two APIs will be the most successful, as is shown in Figure 2.6. Convergence of SIP and HTTP protocols into the same Application Server offers, among others, a key advantage. It is not necessary to have two different servers (HTTP and SIP), SO it reduces from maintenance problems, and eases user and configuration provisioning. Seve