View from Abroad

July 2007

_____________

SIP Protocol at the Center of Evolving IP-Based Applications and Services

The computer and telecommunications industry has come along way since the 1990s, when roughly one percent of all voice traffic involved voice over IP (VoIP) technology. The residential VoIP market in the U.S., for example, is expected to grow from 10.3 million subscribers last year (2006) to more 44 million in 2010, with VoIP systems installed in 62% of broadband households by that time, says market researcher International Data Corp. (IDC).

Fueling that growth are underlying technologies and protocols like H.323 and the Session Initiation Protocol (SIP), the former developed by the International Telecommunications Union (ITU) and the latter by the Internet Engineering Task Force (IETF). (As 2in10 Associate Nick Shelness points out, H.323 is an earlier protocol family than SIP, which makes some use of some underlying IETF protocols such as RTP.)

Basically, SIP and H.323 are competing standards used for establishing communications sessions in an IP network. These sessions might be simple two-way VoIP telephone calls, or more complicated collaborative messaging and multimedia conference sessions involving PCs, cell phones and wireless mobile handsets.

While SIP and H.323 share some similarities in the way they handle IP-based networking and functions, they are structurally different.   While H.323 is a slightly overweight soup to nuts protocol solution, SIP is a lean and mean mediator that is just concerned with initiating, executing and successfully completing an IP session.   Both are equally effective, although SIP is increasingly becoming the protocol of choice among today’s developers of IP telephony applications. 

Clearly the future is moving towards SIP, says experts like Doug Tucker, CTO of Ubiquity Software who was a member of the committee that developed H.323 more than a decade ago.

“H.323 is a very constrained infrastructure.  It was designed for a very specific deployment architecture and specific usages,” he notes.  While “SIP is a much more open protocol that allows the applications to define the usage and topology that SIP is applied to.”

(Ubiquity Software Corp. plc is based in Cardiff and has corporate offices in the US and Canada.  Avaya, Inc. acquired the company in Jan. 2007 for approximately US$144 million.)

Applications and programming are layered on top of the SIP infrastructure to develop communications solutions and collaborative environments, explained Tucker.  It does not specifically impact the applications or how they are developed, but make it easier for these applications to make use of and define a wireless or wired communications network.

This distinction is important to wireless carriers, since they can use Ubiquity’s SIP Application Server (SIP A/S) to deploy next generation applications and services and thereby generate more revenue from subscribers through these multimedia offerings, noted Ronald Gruia, Principal Analyst of Emerging Telecom at Frost & Sullivan. 

The market for such services, based on SIP, is expected to reach $4.7 billion by 2009, says market researcher Yankee Group, as a range of new applications and products are deployed that make use of enhanced IP services.  These also include VoIP, Web conferencing, instant messaging and gaming applications.

Large enterprise can also use the Ubiquity server to develop and deliver SIP-based applications to its mobile workforce that fluidly meld video, voice, data, and location-based services into a single application.

Tucker speaks with some degree of authority on these standards since he was a member of the committee created H.323 10 or 12 years ago.  It wasn’t viewed as a general applications infrastructure, he says, while SIP was really built around the Internet protocols and a very distributed deployment model and also a very open usage model. 

It’s much better suited to today’s view of where applications are going, which are rapidly breaking down the notion of vertical applications and approaching more of a horizontal services capability that are more dynamically grouped into point applications for the enterprise, he points out.

Why haven’t we heard more about SIP until now?  Quite simply, when it was first introduced more than a decade ago it was positioned to emulate the standards of traditional phone networks, which was a very tough fit because SIP doesn’t operate in the same type of call model or structure of traditional telephony. 

"It wasn’t until several years ago that people realized that the IP service network was much less expensive from an operational standpoint and carriers started to pull IP into their communications networks as a cost reduction.

“Now, they’ve ridden the cost-curve down as best they can and now they are looking at how to generate new revenue through services, and that’s further fueling the uptake into IP networks,” says Tucker.

As a result, more companies are looking to employ SIP and SIP applications into their evolving wireless technologies, including mobile WiMAX, which will be commercially deployed in the U.S. in early 2008.  This means more channels and more potential routes to market for new communications products and technologies worldwide.