hout modifying the SIP protocol in any way. 2.2.1.4 MEDIACTRL Media Server Control (MEDIACTRL) is a new IETF working group formed to create a standard protocol for controlling media servers. The group intends C 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security Signaling stack stack Control client Control channel Control server FIGURE 2.3 Illustration of a simplified view of the proposed mechanism. to focus on the use of SIP and XML for its protocol suite. Figure 2.3 shows their proposal of a framework and protocol for application deployment where the application logic and processing are distributed. Control channels are negotiated using SIP standard mechanisms that would be used in a similar manner to create a SIP multimedia session. It highlights a separation of the SIP signaling traffic and the associated control channel that is established as a result of the SIP interactions. The use of SIP for the specified mechanism provides many inherent capa- bilities which include: Service location. Use SIP Proxies or Back-to-Back User Agents (B2BUA) for discovering Control Servers Security mechanisms. Leverage established security mechanisms such as Transport Layer Security (TLS) and Client Authentication Connection maintenance. The ability to re-negotiate a connection, ensure it is active, audit parameters, etc. Agnostic. Generic protocol allows for easy extension A CONTROL message is used by the Control Client to invoke control com- mands on a Control Server. 2.2.1.5 Media Server Control API (JSR2309) The goal of JSR 309 is to specify an API that standardizes access to external media server resources and to provide their multimedia capabilities from services built on application servers. JSR 309 defines a mechanism to provide: Media network connectivity to establish media streams IVR functions to play/record/control multimedia contents from a file or streaming server A way to join/assemble IVR function to a network connection, following any topology, to compose conferences, bridges,