  Delay Tolerant Networks (DTNs) are sparse mobile networks, which experiences
frequent disruptions in connectivity among nodes. Usually, DTN follows
store-carry-and forward mechanism for message forwarding, in which a node store
and carry the message until it finds an appropriate relay node to forward
further in the network. So, The efficiency of DTN routing protocol relies on
the intelligent selection of a relay node from a set of encountered nodes.
Although there are plenty of DTN routing schemes proposed in the literature
based on different strategies of relay selection, there are not many
mathematical models proposed to study the behavior of message forwarding in
DTN. In this paper, we have proposed a novel epidemic model, called as CISER
model, for message propagation in DTN, based on Amoebiasis disease propagation
in human population. The proposed CISER model is an extension of SIR epidemic
model with additional states to represent the resource constrained behavior of
nodes in DTN. Experimental results using both synthetic and real-world traces
show that the proposed model improves the routing performance metrics, such as
delivery ratio, overhead ratio and delivery delay compared to SIR model.
