Cluster Head (CH) is also a wireless sensor node, which has more computational power comparing to all other sensor nodes. These cluster Heads are responsible for sharing all other sensor nodes information to the Base Station. The Base Station selects the Cluster head.
Cluster Heads broadcasts identifier message to all other wireless sensor nodes (Adjacent Nodes). The adjacent nodes replies with identifier acknowledgement to the cluster head.
The Cluster Head manages the routing table and also the details of all the nodes in its group. The Cluster Head also maintains details about other groups Cluster Head and its address with the help of Base station.
The normal sensor node in a group maintains a table that contains information of its Cluster Head address and the common identifier generated by the Cluster Head.
The address of the Cluster Head that has already involved in routing has stored in every packet, it is used for verification by other Cluster Head.
When a source node in a need of route to deliver packets to the destination node, it sends Route Request message to the Cluster Head, the Cluster Head uses its common identifier to verify the packets.
The Cluster Head checks whether the destination node is in house, if the destination node is present under its group, then it sends the packet directly. If the destination node is not in house then it sends Route Request message to Base Station, The Base Station intent passes it to the Cluster Head which manages the Destination node. The Cluster Head passes then passes packets to the Destination node.
The sensor node under motion makes new route request to the Cluster Head, then Cluster Head passes the information to the base station. Source node and destination node under range directly communicates with each other with the help of adjacent nodes.
If the source node detects destination node is under its range it sends route change request to cluster head and it starts sending packets directly to the destination node(shortest path) through nearby adjacent nodes.