Why do half duplex Ethernet 10BASE-T topologies have a slower data transmission rate than full duplex Ethernet 10BASE-T topologies?
Half duplex Ethernet 10BASE-T technology restricts the media to having one channel for transmit and receive. For example if a host is communicating with another host (directly connected), the host sending data has... access to the wire and transmit. The reply from the other host must wait until the other transmission is completed before it can start to send a reply. In the event that these two hosts were communicating in a full duplex 10BASE-T Ethernet environment, the two hosts would have two channels, separating out transmit and receive.