One of the biggest hurdles for developers and users of softphones has been the pesky issue of NAT transversal. Without getting too technical, NAT which stands for Network Address Translation is what allows one IP address to be routed to many and have the right data end up on the right device from the outside world.
Softphones which are endpoints for IP telephony are often behind the router, some of which don’t handle NAT very well, like my first and early D-Link Wireless Router circa early 2001. Fortunately, XTEN has released XTunnels, which should solve the problem.
I’m a fan of XTEN. I use both their X-PRO for iConnectHere and FWD, as well as X-Ten Lite for Vonage. Many a carrier has turned to them, SipPhone being one, because their software is very good and they’re incorporating G711 and G729 into the compression scheme. Now with Xtunnels, any softphone manufacturer can get the benefit of their smarts.
With Wi-Fi handsets coming on stream in bigger ways, the need for this is enourmous, otherwise a hotspot may not be the cool place to make a call from.