Measuring the parameters of TCP and conducting performance tests allow us to accurately study the connectivity characteristics of WLANs. It also helps us to investigate how TCP traffic will affect other traffics such as video, audio, etc. In this paper, we measured the performance of TCP/UDP in IEEE 802.11 wireless networks in the one-hop and multi-hop scenarios using throughput and bit error rate (BER) as the measurement metrics. We use three parameters in the experiments, namely, "signal to noise ratio (SNR)", "packet size in TCP layer" and "TCP receiver-advertised window (rwnd)". Our experiment results show that the SNR is the most important one for transmission. The packet size also affects the TCP throughput greatly, especially when the SNR is low. The value of TCP receiver-advertised window should be set properly to get the best performance of TCP in wireless networks