There are three main types of media access methods for sharing a transmission medium: contention, token passing, and demand priority. Contention methods like CSMA/CD and CSMA/CA use carrier sensing and collisions to determine when nodes can transmit. Token passing like IEEE 802.5 uses a token that is passed between nodes to determine which node has permission to transmit. Demand priority prioritizes different data types and gives precedence to higher priority data if contention occurs at hubs.