A fundamental assumption of the TCP protocol is that packet losses indicate congestion on the network. This is a problem when using TCP over wireless links, because a noisy radio transmission may erroneously indicate congestion and thereby reduce the TCP sending rate. Two partial solutions, that improve the quality of the radio link, are power control and link-level retransmissions. By modeling these two lower layers of control loops, we derive an analytical modei of the delay distribution for IP packets traversing a link. We investigate the effect on TCP, in particular the performance degradation due to spurious timeouts and spurious fast retransmits caused by delays and reorder on the link. It is shown that the models allow us to quantify the throughput degradation. The results indicate that link-level control and TCP interact, and that tuning one or the other is needed in order to improve performance.