Vint Cerfs Facebook profile includes a picture of him wearing his favorite t-shirt: it reads IP on Everything. Cerf co-authored the 1973 paper that led to TCP/IP being used as a means to interconnect previously incompatible computers and networks associated with the ARPANET. Increasingly, Session Initiation Protocol (SIP) is playing a similar role as the common denominator interconnecting diverse communication devices and networks. And although the protocol geeks either love or hate SIP, its rapid adoption makes it impossible to ignore.
Although Microsoft and Cisco offer competing visions of the future of communication, they both support SIP. Skype rose to fame via a proprietary protocol, but Skype utilizes SIP as the means to connect with the telephone network. Several dozen device manufacturers from Nokia and Philips to Sony and Siemens offer SIP-enabled devices, and virtually every other consumer electronics company on the planet plans to roll out SIP-enabled devices over the next 12 months. Ten million SIP-enabled phones have sold to enterprise customers. Avaya, Nortel and Siemens may argue over who has the best features, but they all support SIP.
The entry-level price for an SIP telephone fell to $40 in 2007 from $400 in 2002. Chip manufacturers like Texas Instruments and Broadcom already have third-generation functionality in the pipeline. Best Buy et al do not currently carry SIP phones, but web sites dedicated to SIP-enabled products (e.g. telephonydepot.com) arrived in 2007. Hundreds of companies (e.g. Betamax Group) bridge SIP calls to the traditional telephone network. Fring provides free software that turns mobile handsets into SIP clients enabling voice and IM functionality via Wi-Fi and 2G or 3G data plans.
The patent woes of SIP-based Vonage seem to have squelched the stream of SIP VoIP startups for the time being. For some 20 years, the TCP-IP protocol that Vint co-created achieved very little in the way of public awareness until the arrival of Mark Andreessens web browser. Cheap telephone calls represent SIPs thin edge, but SIP still needs its web browser moment.
Solutions exist for the early obstacles encountered by SIP, such as NAT and firewall traversal. Adobes plans for integrating SIP into Flash may go a long way toward unleashing more creativity. SIP continues to evolve with peer-to-peer SIP arriving to challenge client-server SIP during 2008. Yet we remain in the horseless carriage phase, in which everything gets framed in terms of the old model. SIP phones do little more than replicate the features and functions of traditional telephones.
In any case, to quote Victor Hugo, Nothing is as powerful as an idea whose time has come. In the 100 years between 1876 and the 1980s, the painfully slow pace of innovation associated with wired telephone monopolies meant that a mere 600 million people were able to use the telephone as a means of communication. Over the next 25 years, competition between cellular carriers increased the pace of innovation enough to allow the technology to reach two billion people. Now, an even faster pace of cost performance improvements positions an infocom ecosystem of SIP devices as the solution to bring communication to four billion people. The time has come for SIP.