Bus and tree use a multipoint medium. For bus, all stations attach through appropriate hardware interfacing known as a tap to a linear transmission medium or bus. Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received from the bus. Tree topology - stations are attached to a shared, branching transmission medium. Generalization of the bus topology.
Transmission medium is a branching cable with no closed loops.
Tree layout begins at a point called the headend. A transmission from any station propagates throughout the medium and can be received by all other stations. C. Star Topology each station is connected directly to a common central node. Each station attaches to a central node, called a star coupler. Ring is appropriate for very high speed links over considerable distances.