The packets generated by each node are transmitted to surface sink using broadcasting and multi-hop communication . In this communication, sending node includes its depth and the routing information in data packet and broadcasts it to all the nodes within its transmission range. However only shallower nodes (i.e., a node with depth lesser than the transmitting node) are allowed to respond to this broadcast. Only those shallower nodes which are farther than the depth threshold become eligible for forwarding. All the eligible nodes holds the packet for their respective holding time which is inversely related to forwarding function. If these packet holding nodes receive the copy of the same packet with-in their holding time they discard the packet and assume that a more eligible node has forwarded the packet. However if holding time is elapsed and no copy is received, node considers itself as the best forwarder and broadcasts that packet. This process is repeated by all nodes till the packet is reached to surface sinks. In this way each time a node with maximum value of forwarding function, gets minimum value of holding time and becomes next forwarder. This communication process involves certain terms which are needed to be explained.