Increasingly, Session Initiation Protocol (SIP) is the common denominator interconnecting diverse communication devices and networks. Like it or love it, the rapid adoption of SIP makes it impossible to ignore.

Vint Cerf’s 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 Andreessen’s web browser. Cheap telephone calls represent SIP’s 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. Adobe’s 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.

By Daniel Berninger

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  1. Indeed, the time has come for SIP

  2. Very informative. Keep it up!


  3. Great post! I like it very much. Go SIP!

    I love it to squeeze out my phone bill with SIP. Betamax already gave me so many freedays that I virtually don’t have to pay for phone calls anymore. Tringme and also the Voxalot click to call widget on my website let people from all over the world call me for free.

    With callback to my mobile phone and Betamax as SIP provider in the game I can call the world from my cell phone for prices cheaper than local calls with my own mobile network operator. That’s why I use Voxalot’s mobile callback even for local mobile calls.

    All thanks to SIP.

  4. Apple iChat AV, introduced in May 2002, is also SIP based.

  5. this is what I am talking about! Technology at its best!

  6. Verizon’s patent claims that lead to the Vonage infringement would not hold up in court against a defendant with the financial resources to adequately defend themselves.

    This was a calculated tactical move on Verizon’s part against a wounded enemy. In the long term (Long term meaning 2-5 years), I do not believe these will hold any water. You have not seen them pursuing it beyond Vonage, they have no interest in tangling with a worthy adversary.

    There is a wealth of substantially close prior art out there. The methods and technologies Verizon is laying claim to were in use well before their application.

  7. Agree, so far SIP has not been used for much beyond what the PSTN. But then the PSTN (including cellular) has grown to >2Billion endpoints. And that is still growing, so don’t see how or why the “horseless” paradigm will change. Maybe with IMS…

  8. [...] Session Initiation Protocol (SIP) is certainly on the rise these days. GigaOm has a great article today examining its progress towards becoming the dominant standard of real-time [...]

  9. “TCP-IP protocol [had] little in the way of public awareness until the arrival of [the] web browser…SIP still needs its web browser moment.”

    The difference is, TCP-IP was the protocol behind the browser from day one. There were no “legacy” browsers in 1990. SIP has a much tougher battle in that there are several billion non-SIP telephony devices out there.

    I like SIP, and it has a strong foothold. But we are still early enough in the adoption process that this whole thing could go another way. More here: http://www.callthecloud.com/?p=49


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