In a study on VPN hardware and software by Infonetics Research, most respondents cited technology change as the main reason they replace VPN products, an indication that vendors would do well to capitalize on technology shifts (such as the shift from IPSec to SSL) to enter the market or disrupt market leaders. Security remains the top concern when implementing VPNs, rated a barrier by over a third of the respondents. Education and retail respondents come up as "cost sensitive" in a variety of questions in the study, including what constitutes a strong barrier to implementing VPNs. Most respondents keep VPN products in use for 2-4 years across, but the more cost conscious verticals (education and retail) tend to stretch more products into the 4-6 year category. The total penetration of SSL VPN for remote access (either as a primary or secondary technology choice) is fairly high, with 39% of remote access respondents using it now. Only 14% use fully managed VPN services and the money is spread across a wide range of providers, primarily RBOCs and IXCs.