Despite lingering questions about overall quality of service, enterprises are becoming more comfortable with the use of SIP trunking as a low-cost alternative to legacy telecom services, a change that will result in a growth in deployment from 8.5 million SIP trunks in 2009 to 24.3 million trunks in 2013, according to the latest report published by Heavy Reading IP Services Insider, a subscription research service from TechWeb's Heavy Reading.

SIP Trunking Gains More Ground With SMBs focuses on the growing use of SIP trunking in enterprise applications, focusing on growing uptake by small and medium-sized businesses. It defines SIP trunking and provides a comparative analysis of solutions. This report also provides an industry analysis, covering industry drivers, finances, and customer demographics. Finally, this report profiles 10 leading vendors in the market.

"In its simplest form, SIP trunking is a service offered by an Internet telephony service provider (ITSP) that permits businesses with an installed private branch exchange (PBX) to use voice over IP (VoIP) outside the enterprise network by using the same connection as the Internet connection," says Denise Culver, research analyst with Heavy Reading IP Services Insider and author of the report. "SIP trunking is a way for enterprises that once were considered too small to afford leased-line services to gain competitive edge against larger competitors, but at a much lower price point."

Before moving to SIP trunking, however, SMBs have to be convinced that IP-based services can deliver the service quality they require for baseline applications, especially voice service, Culver says. "Doubts about service quality remain, but it's clear that more small businesses are becoming convinced that IP-based networks will meet their needs, which will lead to significant growth in SIP trunking deployments over the next three years," she adds.

Key findings of SIP Trunking Gains More Ground With SMBs include the following:

• SIP trunking has many benefits, including enabling service providers to retain customers, helping enterprises expand out of region, and driving the move toward hosted IP Centrex services.
• Over the next 18 to 24 months, SIP trunking likely will become the foundation and conduit for the delivery of cloud-based enhanced services because of its flexibility and extensibility.
• SIP trunks provide an average of 50 to 70 percent cost savings per trunk, when compared to TDM circuits.
• Better education of end users is needed regarding how SIP trunks are implemented and how QoS is achieved.
• As more enterprises transition toward IP-PBXs, the demand for SIP trunking will increase.

SIP Trunking Gains More Ground With SMBs is available as part of an annual subscription (six issues) to Heavy Reading IP Services Insider, priced at $1,595. Individual reports are available for $900.