CDMA2000 Wireless Data Services 
Understanding Simple IP and Mobile IP ▀  
Cisco ASR 5000 Series Product Overview ▄  
Figure 75.  Mobile IP, FA and HA Tunneling/Transport Methods 
 
 
How Mobile IP Works 
As described earlier, Mobile IP uses three basic communications protocols; PPP, IP, and Tunneled IP in the form of IP-
in-IP or GRE tunnels. The following figure depicts where each of these protocols are used in a basic Mobile IP call.