The front runner in converged communications signaling today is Session Initiation Protocol or SIP. SIP has emerged...
as the leading protocol for VoIP and other real-time media communication over the packet network. There are several reasons for the popularity and success of SIP.
First, SIP is a protocol that was conceived from the ground up to work on IP networks. It was developed by the IETF and builds upon other protocols already developed for the IP world. SIP is a text-based protocol that works well with the markup-based distributed application architecture of the Web world. It uses similar addressing as the Internet and utilizes many of the components of Internet architecture for its workings (DNS servers, for example). This makes it easier to integrate with applications built on standard computing platforms and operating systems, promoting convergence.
Second, SIP is extensible and can work with multiple media formats and payloads to enable a wide range of applications. There are several standards that have been created over SIP for applications like instant messaging, resource management, media streaming (video) and presence management. This extensibility allows for innovative new applications to be created. SIP is suitable for enterprise applications as well as highly scalable carrier applications. It is apt for wired and wireless networks and is able to take advantage of the security and AAA properties of the networks.
Third, SIP is now available as part of the infrastructure in most endpoints, particularly desktop operating systems. This makes it extremely convenient for application developers to build applications based on SIP. As with any communication standard, interoperability is key and the SIP community has ensured that the major implementations work well together.
The open source community has embraced SIP and has done a lot of work to create and promote SIP-based applications. This also has a big effect of spreading the expertise and seeding the basic code required to build SIP applications.
I think we will be seeing a lot more application level innovation enabled by SIP in the coming months and years. SIP facilitates the application level convergence of voice and data applications.
About the author:
Sanjeev Sawai is the vice president of research and development at Envox Worldwide (www.envox.com), a voice solutions provider. With more than 15 years experience in the development of telecommunications and embedded systems, Sawai is responsible for investigating and evaluating new standards and emerging technologies in the voice solutions market.