Tree Topology

A tree topology is a variation of the star topolgy. As in star topology devices are linked to central hub that control the traffic. However in tree topology the secondry central hubs are again linked to a central hub. In tree topology this central hub is the active hub to control the secondry hubs and traffic.
An active hub contains a repeater (hardware device) that regenrates the bit patterns before sending. It strengthens the transmission and boosted signal travels long distance.
The secondry hubs can be active or passive. The passive hub only provide a simple connection to the central hub and attached devices.

Advantages:

1. This is less expensive.

2. One link and one input/output port  is required.

3. Easy installation and reconfiguration.

4. Less cabling is required.

5. If one link fails then other remain active to communicate.

6. Make fault identification and isolation easy.

7. More devices can be attached.

8. It allows the network to isolate and prior the specific computer of a secondary hub to another computer of another secondary hub.

Disadvantages:

1. The only major disadvantage is that if the central hub or controller fails then the entire network goes down.