Tree topology is a combination of linear bus and star topologies.
Tree topology consists of group of star-configured workstations connected to a bus backbone cable.
In this topology every node is not directly connected to central node or hub. Most of the nodes are connected to secondary hub, which in turn is connected to the central hub. Each secondary hub functions as the originating point of a branch to which other nodes connect.
Advantages of Tree topology
Tree topology is easy to extend as it is divided into subunits of star-configured workstations. Thus it can be easily extended to add new nodes or branches.
Defective node can be easily identified in tree topology.
The distance to which a signal can travel increases as the signal passes through a chain of hubs.
Disadvantage of Tree topology
As the tree topology is entirely dependent on bus backbone cable to which other star configured workstations are connected so if the bus line breaks entire network service is disrupted.
Tree topology is difficult to configure and wire as compared to other topologies.