In a method and apparatus for providing system interoperability in wireless communications an IP based client-server application maintains a proper set of PDP contexts while a mobile is connected via an IP based system. The application client resides in the mobile and the server resides within the network at a common anchor point between the IP based system and a PDP contexts based system. The PDP contexts are kept up to date but on hold until a handover occurs for the mobile from the IP based system to the PDP contexts based system.