Mobile adhoc network is self-configurable and adaptive. Due to node mobility we cannot predict load on the network which leads to congestion, one of the widely researched area in manets. A lot of congestion control techniques and metrics have been proposed to overcome it before its occurrence or after it has occurred. In this survey we identify the currently used congestion control metrics. Through this survey we also propose a congestion control metric RFR(resource free ratio) which considers three most important parameters to provide congestion free route discovery. Further we show the results of node selection based on fuzzy logic calculations using the proposed metric.