**2.2.2 CGSR Protocol (Cluster head Gateway Switch Routing protocol)**

This protocol is based on the DSDV routing algorithm. Mobile nodes are collected inside packets, and a cluster head is selected. A gateway node is a node in a communication interval between two or more cluster heads. In a dynamic network, the idea of a cluster head can decrease the efficiency resulting from the frequency of selecting cluster heads. Thus, CGSR uses an algorithm to change the last cluster or LCC. [Murthy S and Aceves J. J, 1996].

In LCC, a change in cluster head is made when changes are made in the network. In this state, the origin sends the packet to its cluster head; the cluster head sends this packet to the gateway node to which it and the node which is located in the route of destination are connected. The gateway sends the packet to another cluster head and this action continues until the cluster head receives the destination node of packet. Finally, the destination cluster head sends the packet to the destination node [Boukerche. A et al, 2011]. Figure 4 indicates an example of a CGSR routing plan.

Fig. 4. Example of CGSR routing from node 1 to node 12
