Studies of transport protocols for ad-hoc networks have shown that flow control mechanisms based on rate feedback obtained from the network can provide better control in dynamic multihop ad-hoc environment than the TCP window-based congestion control mechanism. A number of rate estimation techniques have been proposed in the literature as key components of rate-based flow control mechanisms suitable for ad-hoc networks transport protocols. This paper examines performance of two rate based flow control mechanisms proposed in the literature. The results indicate that the Saturation Throughput Estimate (STE) technique, based on measurement of channel utilisation in the neighbourhood of a node, proposed in [I] leads to better flow control and transport performance than the other technique, based on the measurement of queue utilisation at a node, proposed in [2].