This paper presents a detailed packet-level simulation comparing four multi-hop wireless ad hoc network routing protocols: DSDV, TORA, DSR, and AODV. The simulation environment is extended to accurately model the MAC and physical-layer behavior of the IEEE 802.11 wireless LAN standard, including realistic wireless transmission channel models. The results are based on simulations of 50 mobile nodes moving about and communicating with each other. The performance of each protocol is analyzed, and the design choices that account for their performance are explained. The four protocols are evaluated using three metrics: packet delivery ratio, routing overhead, and path optimality. The results show that DSR and AODV-LL perform particularly well, delivering over 95% of the data packets regardless of mobility rate. DSDV-SQ fails to converge at pause times less than 300 seconds. TORA has the highest overhead, while DSR has the lowest. The study also highlights the impact of node mobility and network load on the performance of the protocols.This paper presents a detailed packet-level simulation comparing four multi-hop wireless ad hoc network routing protocols: DSDV, TORA, DSR, and AODV. The simulation environment is extended to accurately model the MAC and physical-layer behavior of the IEEE 802.11 wireless LAN standard, including realistic wireless transmission channel models. The results are based on simulations of 50 mobile nodes moving about and communicating with each other. The performance of each protocol is analyzed, and the design choices that account for their performance are explained. The four protocols are evaluated using three metrics: packet delivery ratio, routing overhead, and path optimality. The results show that DSR and AODV-LL perform particularly well, delivering over 95% of the data packets regardless of mobility rate. DSDV-SQ fails to converge at pause times less than 300 seconds. TORA has the highest overhead, while DSR has the lowest. The study also highlights the impact of node mobility and network load on the performance of the protocols.