There are others solutions than Calypso. The best solution today is probably Birdstep Mobile IP Client which is the only non-propetary solution available and this is also the solution most major companies (Intel, Cisco, Lucent, Pctel,Alcatel, Ericsson, Hp, Nortel, Motorol, Capgemini and more) work with, and its also on the market today. Other companies which have propetary solution include Ecutel, Netmotion, Ipunplugged and Netseal. Calypso is probably one or two year behind these companies. All of these companies have products in the market and most of them have been tested by several major players.