The testbed configuration to test Mobile IP is shown in the next figure:
![\includegraphics[width=10cm]{maqueta-5subredes_MIP.eps}](img2.png)
The network configuration is (first IP address available in the network/ netmask):
The Mobile Node (IP address 212.128.1.45) uses a WaveLAN card to connect to the Foreign Agents (FA3, FA4 and FA2). The FA's have WaveLAN cards too, and all the WaveLAN cards are configured in Ad-Hoc mode.
The Mobile Node (MN) goes from one network to other, registering in the corresponding FA. The MN never changes its IP address (we use FA Decapsulation). In this configuration (FA Decapsulation), all the packets from the Correspondent Node (CN) to the MN goes to the Home Agent (HA) that encapsulates them and sends them to the FA across a tunnel. Then, the FA receives the encapsulated packets, decapsulates them and sends them to the MN which is registered in its network.
Hierarchical FA's are used in this testbed. This occurs between the FA1-FA3 and the FA1-FA4. Thus, the MN changes quickly from Network 3 to Network 4 (and vice versa) because the HA establishes the tunnel with FA1, and then, depending if MN is registered in the FA3 or the FA4, a tunnel will exist from FA1 to the FA3 or to the FA4. When MN, for example, goes from FA3 to FA4, the tunnel between FA1-FA3 is eliminated and a new tunnel will be created between FA1-FA4. A case where doesn't exist hierarchical FA's occurs, for example, when the MN goes from FA3 to the FA2. The connection establishment is higher because a tunnel from HA to the FA2 is created and this is slower than the previous case where the new tunnel was created from FA1 to FA3/FA4.