The efficiency of service of Underwater Acoustic Networks is restricted by the acoustic channel characteristic, such as the low bandwidth , high varying multipath and elevated noise levels. In addition, the lifetime of Underwater Acoustic Networks is influenced greatly by the limited battery power. This paper designs an Underwater Acoustic Networks and poses the data link layer protocols including the logical link control protocol and the media access control protocol. The simulation results have demonstrated that the protocols are of certain applicability in underwater acoustic channel environment that maximize throughput and reliability while minimizing end-to-end delay. In the event of low offered load, the protocol can satisfy the requirment of Underwater Acoustic Networks.
