RouteScience is introducing an add-on to its small office VPN box that expands the ability to intelligently select which ISP link to send traffic over from these minor sites.RouteScience\u00a0is introducing an add-on to its small office\u00a0VPN\u00a0box that expands the ability to intelligently select which ISP link to send traffic over from these minor sites.Called PathControl 3350, the device works in tandem with the company's existing small site box called PathControl 3300 to boost the number of ISP links it can optimize from two to four.The gear also adds the ability to support reports on how often the gear actually changes the path used and how much performance is improved as a result. The 3300 did not have this reporting capability.PathControl equipment sits on a corporate LAN and acts as a peer to Border Gateway Protocol (BGP) routers. In the absence of a PathControl device, BGP is used to choose which of multiple ISP connections to use based on which path requires the fewest router hops. This is often not the optimal choice because BGP doesn't factor in important criteria such as delay across a path or the price of a particular path.PathControl equipment\u00a0 does consider these factors and makes changes to router tables to divert traffic accordingly.PathControl 3300 was designed to pick the better ISP link for traffic to follow if a smaller corporate site had just two Internet connections that were being used to support an Internet-based VPN back to a headquarters. Headquarters was also equipped with a PathControl box, a more expensive PathControl 5000-series device. The boxes probed back and forth to each other to determine which was the best ISP to use from each end.To get support for reporting and the ability to handle more than two ISPs required a PathControl 5000-series chassis, which at $100,000 was more expensive than customers were willing to pay for smaller sites. A PathControl 3300 plus a PathControl 3350 gives the functionality of a PathControl 5500-series box for $60,000, RouteScience says.PathControl 3350 costs $30,000 by itself and is available next month.