Sh Sharifi - Computer Engineering Department, Urmia University, Urmia, Iran
S Yousefi Rad - Computer Engineering Department, Urmia University, Urmia, Iran
J Bagherzadeh - Computer Engineering Department, Urmia University, Urmia, Iran

Delay Tolerant Networks (DTN) enable data communication in sparse regions, where long delay and intermittent connectivity can be tolerated. In DTNs, end to end path may not be existed, therefore, packets may be stored in nodes and be forwarded in appropriate conditions. Public transportation system has some characteristics that can be useful in DTNs. In this system, routes are predefined and system agents (such as buses, taxies, trams etc...) pass on their specific routes. Having this knowledge about transportation routes, we can determine optimal relay node that ensures delay tolerant connectivity. In this paper, we model optimal network configuration problem using integer linear programming (ILP). The proposed model minimizes network cost and routing delay, simultaneously. Based on the proposed ILP model we use a DTN routing mechanism in which packets are stored, carried and forwarded to their destinations. Simulation results show the performance of the defined method.

Delay Tolerant Networks, Public Transportation System, Routing, Relay Nodes