This article originally appeared in the March 2013 issue of INTERNET TELEPHONY.

Session border controllers have been around for a long time, but there’s still ample opportunity for them related to SIP trunking, among other potential applications such as unified communications normalization. Indeed, Oracle (News - Alert) Corp.’s recent move to purchase SBC company, Acme Packet, for $2.1 billion emphasized the value of the session border controller and the fact that these products still have a long runway ahead of them.

The vast majority of SBCs deployed today are used to interconnect carriers.  

It’s an established market, but not a mature one, so we can still expect to see huge amounts of growth in this arena, says David Tipping (News - Alert), vice president and general manager of the SBC business unit at Sonus Networks. On the enterprise front, there are many large businesses that have deployed VoIP and now want to extend it out so they don’t need PRI gateways for external calls, he says.

The information within a session is a real driver now in interest around SBCs.

SIP trunking revenue grew 23 percent in the first half of 2012 compared to the second half of 2011, led by strong activity in North America, according to Infonetics (News - Alert). The research firm predicts that $377 billion will be spent on business and residential and SOHO VoIP services over the 5 years from 2012 to 2016, driven primarily by SIP trunking and hosted VoIP/UC services.

T1 lines are still the most popular way to do trunking today, but SIP trunks continue to make headway, with a third of enterprises surveyed by Infonetics using SIP trunks today, and 42 percent planning to do so by 2014.

Indeed, SIP trunking has only scratched the surface, notes Jason Rolleston, director of product management for the routing services group at Cisco, which Infonetics recently named the marketshare leader in enterprise SBCs. That’s because voice is a notoriously slow-moving space, given that people are very cautious about making changes to this mission-critical capability.

“There are a lot of inhibitors to moving” like changing numbers, for example, Rolleston says. So “this transition will take a long time.”

Worldwide revenue for enterprise SBCs hit $82.5 million in the first half of 2012, according to Infonetics Research (News - Alert). The top SBC applications among service providers, according to Infonetics, are interconnection to other service providers, SIP trunking, and hosted business VoIP.

While Cisco is now leading the enterprise SBC space, Acme Packet (News - Alert) is still up front in the service provider SBC rate. As discussed in a recent TMCnet posting by Peter Bernstein, Michael Elling of Information Velocity Partners, LLC, noted three facets of Oracle’s recent move to buy Acme Packet.

One, Oracle's acquisition of Acme underscores the impact the smartphone is having on service providers and IT organizations. BYOD, het-nets and multiscreen access require session control down to the device level, as well as highly scalable, robust settlement solutions. Two, IP is growing up. A lot of focus has been about lower-layer infrastructure, transport and access issues, as well as upper layer application scaling (Java) but not on the security, roaming and settlement issues that are present when smartphones continuously cross private and public network boundaries using a plethora of business and personal applications. Session management and security are absolutely critical.

Third, Elling says the question is: Will it have a bigger impact on private IT networks or on the carrier market?  People who have focused on Acme have been talking about the demand for VoLTE by the carriers. But the bigger market may be BYOD, applications that access the cloud (both private and public) and settlement systems between upper and lower layers and across balkanized networks. 

Without robust settlement solutions, we retard new service creation and introduction across the entire broadband IP ecosystem, Elling says. 

On the enterprise side, some SBC vendors are positioning their devices as a way to normalize communications among different vendors’ UC solutions.

But Cisco’s Rolleston says he doesn’t think session management belongs in the SBC. Cisco believes session management is a distinct function that requires a unique solution.

With some SBC companies, especially those with a keen interest in enterprise applications, talking up the role of session border controllers in unifying different vendors’ UC solutions, the question also arises as to what role the SBC might play as WebRTC become more prominent.

Alan Percy of AudioCodes says SBCs have the potential to play an important role here in transcoding, given WebRTC uses a relatively unique codec that phones commonly used in contact centers, and existing UC solutions, typically do not support.

Rolleston of Cisco adds that the SBC is one natural place for WebRTC translation to happen as it hits the enterprise, and that Cisco is looking at that.