SIP To Create A New Generation Of Services

TMC's editors sat down with Paul Doyle, Director of Strategic Solutions, Ubiquity, and asked him what types of opportunities he forecasts for Session Initiation Protocol (SIP), and what impact it will have on VoIP communications in general. His response is below.

Flexible, extensible and open, SIP is galvanizing the power of the Internet and fixed and mobile IP networks to create a new generation of services. Able to complete networked messages from multiple PCs and phones, SIP establishes sessions much like the Internet from which it was modeled. 

In contrast to the longstanding International Telecommunication Union (ITU) SS7 standard used for call setup and management and the ITU H.323 video protocol suite, SIP operates independent of the underlying network transport protocol and is indifferent to media. Instead, it defines how one or more participants� end devices can create, modify and terminate a connection whether the content is voice, video, data or Web-based. SIP is a major upgrade over protocols such as the Media Gateway Control Protocol (MGCP), which converts PSTN audio signals to IP data packets. Because MGCP is a closed, voice-only standard, enhancing it with signaling capabilities is complex and at times has resulted in corrupt or discarded messages that handicap providers from adding new services. Using SIP, however, programmers can add new bits of information to messages without compromising connections.

For example, a SIP service provider could establish an entirely new medium consisting of voice, video and chat. With MGCP, H.323 or SS7, the provider would have to wait for a new iteration of the protocol to support the new medium. Using SIP, a company with locations on two continents could enable the medium, even though the gateways and devices may not recognize it. Moreover, because SIP is analogous to HTTP in the way it constructs messages, developers can more easily and quickly create applications using popular programming languages such as Java. Carriers who waited years to deploy call-waiting, caller ID and other services using SS7 and the Advanced Intelligent Network (AIN) can deploy premium communication services in just months with SIP. This level of extensibility is already making its mark in growing numbers of SIP-based services. Vonage, a service provider targeting consumer and small business customers, delivers over 20,000 lines of digital local and long-distance calling and voice mail to customers using SIP. Delta Three, which provides Internet telephony products, services and infrastructure for service providers, offers a SIP based PC-to-Phone solution that lets PC users call any phone in the world. Denwa Communications, which wholesales voice services worldwide, delivers PC-to-PC and Phone-to-PC caller ID, voice mail as well as conference calling, unified messaging, account management, self provisioning and Web-based personalized services using SIP.