If the source of a packet is within the CZ controlled by the IN, then the packet is handled based on the type of the next hop. The following cases arise:
Next Hop within its CZ: If the next hop is currently in its CZ (this includes the foreign nodes also), the IN just routes and transmits the packet to the next hop.
Next Hop is an OUTSIDE Node: If the MN is currently registered with another IN as a foreign node, whose HA is this IN, then this IN removes the custom Meghadoot header from the packet and tunnels it to the FA of the MN (Figure 3.3).
Next Hop is a REALLY OUTSIDE Node: In this case the IN removes the custom Meghadoot header and forwards the packet according to its routing table. If the destination belongs to the the Internet, the packet is forwarded to the Internet gateway. On the other hand, if it belong to a different Meghadoot Zone, the packet is forwarded to the IN of that Meghadoot Zone.