Modeling efficiency of mobile ad hoc networks in OMNeT++

In this paper, we investigate the pertinence and the relevance of the modeling of proactive routing in mobile ad hoc networks (MANETs) under the OMNeT++ simulator. In such dynamic networks, the constantly changing topology affects the validity of the established routes as time elapses farther from the start of the routing period. In OMNeT++, as is indeed the case of all the other network simulators, the IP model forecasts an IP packet as soon as it receives an upper layer data unit from the upper layer independently of when this packet will effectively be sent by the lower layer (i.e., the underlying MAC). As such, delayed packets will wander through established invalid routes which will amount to poor performances. We first investigate the inherent functioning of the OMNeT++ simulator and exhibit its modeling drawbacks. Then, we propose practical enhancements to accommodate a proper modeling of dynamic networks that provides a priority treatment to control traffic and fills up the IP next hop field only when the MAC is ready to handle the packet. We conducted an extensive set of simulations to compare both implementations using different load and mobility scenarios and performance metrics. These simulations show that our proposal resolves the malfunctioning of current implementations, yet it allows more accurate network performances.