The purpose of the entire Meghadoot protocol is to achieve the best possible data transmission rate, given the constraints. The reduction of control overhead in the CZ by centralizing the route request process is to improve the data transmission rate. Whenever a node needs to transmit data, it sends a route request to its associated IN. On receiving the route, the route is inserted into a packet, irrespective of the location of source and destination.
The source transmits the packet to the first hop in the source route. The first hop, on receiving the packet, increments the current hop field that is present in the source route and forwards it to the next hop3.4. Figure 3.2 shows how multi-hop relaying of packets takes place. However, this behaviour holds only for the intermediate nodes.
At IN, packet handling is entirely different. Broadly, the type of packets can be classified based on their source, i.e., whether the source was inside the CZ or outside.