Dynamic optimal fragmentation with rate adaptation (DORA) is an algorithm to achieve maximum goodput in wireless mobile networks. With the analytical model that incorporates number of users, contentions, packet lengths, and bit error rates in the network, DORA computes a fragmentation threshold and transmits optimal sized packets with maximum rates. To estimate the SNR in the model, an adaptive on-demand UDP estimator is designed to reduce overheads. Test-beds to execute experiments for channel estimation, WLANs, Ad Hoc networks, and Vehicle-to-Vehicle networks are developed to evaluate the performance of DORA. DORA is an energy-efficient generic CSMA/CA MAC protocol for wireless mobile computing applications, and enhances system goodput in WLANs, Ad Hoc networks, and Vehicle-to-Vehicle networks without modification of the protocols.