One of the main contributing factors to a computer network's efficiency is its topology. It is the physical and logical layout of the computer network. Topology considerations are very important in computer networking. When one talks about it, in terms of a computer framework, two aspects need to be taken into consideration, which are its physical and logical features. The physical framework defines the actual physical connections made between computers and the logical topological framework refers to the pathways of signal transmission. According to these frameworks, there are many types of computer network topologies. This includes bus, star, ring, and tree topologies. What is a Tree Topology? It is a hierarchical computer network, that is a combination of star and bus topologies. A star topology is used in construction of local area networks. With one central hub, connected to multiple computers, the star network ensures that if one terminal goes down, all the rest are operational due to direct linking with the central hub, which may be a router or switch. A bus topology involves the serial connection of computers in a linear fashion and a single cable handles the data traffic among all the computers. A tree is created through a combination of bus and ring topologies. This is achieved by integrating the hubs of multiple star networks together, on one bus. Imagine a topology diagram with many star networks, with their central hubs. Then draw lines, connecting only the hubs together to one point. These hubs are generally connected with one main hub, which is the root for the entire network. It allows for multiple hubs to exist on a network which act as roots for terminals connected to them. This tree-like branched structure of networks, provides high scalability. The main hub is the most active terminal, as it controls the whole network, while the subsidiary hubs are passive. A cable TV network has such a topology, with the main feed cable getting divided into smaller branches, which ultimately reach homes. Advantages and Disadvantages Here is an analysis of the pros and cons of this network structure. Advantages are the following:

• It is the best topology for a large computer network, for which a star or ring topology are unsuitable due to the sheer scale of the entire network. Tree topology divides the whole network into parts, that are easily manageable.
• The topology makes it possible to have a point-to-point network.
• All computers have access to their immediate neighbors in the network and also the central hub. This kind of network makes it possible for multiple network devices to be connected with the central hub.
• It overcomes the limitation of star network topology, which has a limitation of hub connection points and the broadcast traffic induced limitation of a bus network topology.
• A tree network provides enough room for future expansion.

The disadvantages are the following:

• Dependence of the entire network on one central hub is a point of vulnerability for this topology. A failure of the central hub or failure of the main data trunk cable, can cripple the whole network.
• With increase in size beyond a point, the management becomes difficult.

While designing a computer network, one must choose a topology, that is ideally suited to specific requirements that you might have. That will entirely depend on the nature of work, for which that network is being designed. A tree topology or hierarchical topology is chosen, when there is one central root server and many subsidiary terminals.