we always want things faster,” says Todd Landry, Senior Vice President at NEC Sphere Communications (www.spherecom. com). “Do I want SIP trunking to be ubiquitous? Sure…but the lag time is needed to build acceptance and have [the industry] find value.”

The advocacy is needed in some sense because of the inertia created by traditional, TDM-based enterprise services. Westerberg admits it’s hard to convince service operators that they can “realize rapid ROI” with SIP, as “it’s competing with a 100-year-old machine that works.”

Some industry participants feel, however, that relatively speaking there has been significant progress. According to James Rafferty, Product Line Director for Media Gateways at Dialogic ( www.dialogic.com), “there are a lot of SIP-based products out in the marketplace, and we are seeing TDM-to-IP switching take hold.” Rafferty believes that SIPConnect is robust enough to work well for most enterprise applications, even if there are “a few RFCs that are not yet complete…. People are using what they’ve got.” There is perhaps more tinkering in the SIP trunking space–“a lot of interoperability testing”–than actual deployments, but that’s somewhat par for the course. “Under the best circumstances, you’d only see significant development beginning five years” after a new technology has launched, Rafferty believes, pointing out that SIP has only really just crossed that five-year mark.

That said, Ingate’s Westerberg does see the industry as having some traction and believes that traction will increase as a couple of industry “demographic” shifts occur. The first is that increase in SIP trunking adoption is inevitable with the proliferation of IP in both enterprise environments (on the LAN) and in networks (in the core). The “middle conversion” (trunking) will take place when enterprises then realize that there is a better-than-TDM voice quality benefit to going IP.

 

From SIP Trunking to

UC Trunking?

The second is more of a cultural shift. Westerberg sees the way younger communications users multitask through voice, instant messaging, and e-mail as being a major catalyst. “The real [SIP adoption] trigger will be when members of the MSN generation become business decision makers; they’ll be asking, “Why can’t I do this?” IP will take over because enterprises need voice integrated with other media.” Patrick Ferriter, Senior Director of Product Management at Polycom ( www.polycom.com) concurs. “SIP trunking is extendable for unified communications,” pointing to emerging codecs like G729, which is becoming “ubiquitous for call center trunking” and other early UC-adopt-er enterprise verticals.

“Most carriers are working with vendors in a way that will impact the adoption of SIP standards” and ultimately the communications business itself, according to Sphere’s Landry. And he sees this SIP buildup as being far more than just TDM voice.

“High-definition calling, new video-oriented codecs, federated voice/video calling, and brokered presence information–when we start to see ‘unified communications’ trunking as opposed to SIP trunking, that will be a truly differentiated service.” He admits the standards for enabling UC trunking are “not anywhere near” ready. That said, the SIP Forum has done a tremendous job of enabling SIP transversals through easy inter-carrier certification processes, and few industry-standard bodies are as progressive–and proactive–in anticipating industry interconnection requirements, which means that this multimedia future of SIP trunking will not be far behind.

This will also be facilitated by alternative enterprise-com-munication strategies built with voice as one application in a field of many. Sphere, for one, is a proponent of enabling SIP trunking as part of an entirely software-based communications platform. These newer strategies will promote IP-to-IP peering across and between enterprises. Carriers will resist it for as long as possible, in the opinion of Ken Kuenzel, founder and CTO of Covergence ( www.covergence.com), as it will further drop prices on T1s and OC3s, but it is inevitable. “Voice will become an application running over an IP network.” The eventual conversion of voice-centric networks into any-to-any transport layers is having a significant impact on SIP-enabled network elements. Take Covergence’s session border controllers. “A session border controller’s function is changing,” says Kuenzel. “While they are still about security and access control, [vendors] are being asked to [make them] the next point of connection for routing applications.” Controllers are being used as mediating devices for managing service quality on application transversals over SIP trunks, “balancing cost versus quality as they find Layer Seven paths.”

 

HD Isn’t Just for Video

Anymore

Multimedia applications might stoke longer term demand for SIP trunking as an all-purpose enterprise pipe, but many vendors are also focusing on rehabilitating the reputation of IP-delivered voice as a premium service, rather than as a cheaper, sub-carrier-class, alternative. Thus, the high-definition (HD) voice proposition is a significant emerging trend in SIP applications. This will also help prime the SIP trunking pump.

“The industry needs to think about VoIP beyond lower phone bills. It’s about great quality and more features,” according to Ferriter, who sees HD voice as a unique opportunity to leverage the increasing amount of IP in the enterprise environment. HD voice applications have been a key component of Polycom’s call control product roadmap for over a year, and from the company’s vantage point, SIP-capable codecs have proliferated through the enterprise premise equipment universe enough to make HD voice both achievable and compelling. “SIPConnect has become standard in IP PBXs,” says Ferriter, who points to the G722 codec as the enabling catalyst, allowing for wideband (7Khz) audio, and thanks to the ADPCM compression, it con-