Impacts of Internal Network Contexts on Performance of MANET Routing Protocols: A Case Study

Performance of Mobile Ad hoc Network (MANET)routing protocols is greatly affected by network contexts. The network contexts actually contain external and internal parts. However, there is relatively little research on the internal part. In this paper, we discuss the impacts of internal network contexts on routing protocol performance. First, a conceptual model is proposed to separate internal network contexts from external ones. Then we do a case study for Ad hoc On-demand Distance Vector (AODV) routing protocol. The parameter TTL_INCREMENT, which is involved in the broadcast of Route Request (RREQ) messages, is chosen as the typical internal parameter. The simulation shows, for varied values of TTL_INCREMENT, the results of performance comparisons between AODV and Optimized Link State Routing Protocol (OLSR) may be opposite. The rate of performance change with node density also shows relativity with TTL_INCREMENT. Further, based on simplified external network contexts, the relationship between TTL_INCREMENT and the overhead performance metric is proved quantitatively.