In most cases a mobile node wishes to talk to some remote computer. For users and applications, the way these computers communicate doesn't matter that much. Using a wired
or wireless network makes no difference as long as the packets arrive. This is why these industry standard protocols, such as TCP and IP, are used. If the applications see some standard interface then they don't need to know if they are using a wireless network or a fixed network, they just see a standard interface. These standard interfaces are extremely important to both application and network designers.