Session Initiation Protocol (SIP) The Session Initiation Protocol (SIP) is a signaling protocol used for establishing sessions in an IP network. A session could be a simple two-way telephone call or it could be a collaborative multi-media conference session. The ability to establish these sessions means that a host of innovative services become possible, such as voice-enriched e-commerce, web page click-to-dial, Instant Messaging with buddy lists, and monitoring and control of remote devices, services and desktops. SIP is a request-response protocol that closely resembles the HTTP protocol; consequently, SIP sits comfortably alongside Internet applications. Using SIP, telephony becomes another web application and integrates easily into other Internet services. SIP is a simple toolkit that application developers and service providers can use to build converged voice and multimedia services. SIP’s view of the network matches that used in the Internet: intelligent devices communicating directly with each other over a simple transport infrastructure. This allows the network to become a commodity and allows any device attached to the network to provide a service to any other. Now with SIP the investment to set up a new service is very small. This brings new service providers into the market, increases competition, which drives down prices, and helps innovation, The following SIP feature show why it is such a powerful framework and why Central Touch chose SIP as the technology base for its suite of IP contact centre application modules.   Mobility: SIP allows a client to register dynamically with a fixed location URL Calls ( and other SIP messages) can now be routed to it using a well-known address, similar to an email address. Flexible message structure: SIP’s message structure makes it much easier to develop new applications or extend existing applications than equivalent existing protocols, such as H.323 which uses the ITU’s opaque ASN.1 encoding standard instead of text SIP is seen as being much simpler and more flexible. Distribution of function between devices: SIP enables requests to be dynamically routed through different devices, enabling functionality to be distributed and requests routed through the relevant devices. Negotiation of supported features: This makes SIP very adaptable., With SIP the media and protocol extensions to be used for a particular call are negotiated between the clients on that call. As a result, SIP can be used to set up any type of media conversation, including voice, video and messaging. Separation of signaling and media: In SIP, the paths of the signaling and the media are totally independent. The signaling and media may traverse different routes through independent sets of devices on different physical networks. Forking: This allows multiple devices to be associated with a single address, so that all or a selection of these devices can be contacted simultaneously or sequentially, according to local policy.