The pervasiveness and the seemingly unpopular nature of unidirectional data transfer has greatly necessitated the efforts of this paper. We investigated the performance of User Datagram Protocol (UDP) over IP-based wireline and wireless networks. The conceptual model was developed and tested using Network Simulator 2(NS2) and its bevaviour was monitored over the two networks. The results of the simulation in terms of effective throughput, packet drop/loss, and bandwidth utilization were presented. It reveals that UDP exhibits improved performance degradation on wired networks and that the high throughput is as a result of the fact that UDP does not have flow control protocol as it does not retransmit lost packets.