Complex sentence: A FullMAC device hides the complexity of the 802.11 protocol from the main CPU, instead providing an 802.3 (Ethernet) interface; a SoftMAC design implements only the timing-critical part of the protocol in hardware/firmware and the rest on the host.
Split into simpler sentences: A FullMAC device hides the complexity of the 802.11 protocol from the main CPU, instead providing an 802.3 (Ethernet) interface. This is in contrast with a SoftMAC design which implements only the timing-critical a part of the protocol in hardware/firmware and the rest on the host.