Tree topology is a structure like branches of tree, tree topology mainly combination of star topology and bus topology. In my previous posts I have discussed Basic Types of Topology in Computer Networks. Now,  topic of discussion is Tree Topology. Tree Topology is a hybrid of Bus Topology and Star Topology. It is highly flexible and provides the advantages of both of its constituents.

Introductory video about Tree Topology

What is Tree Topology in Computer Network?

You can also name it as Tree Topology Network alternatively. This is basically a hybrid topology. It combines the physical and logical layout of both Star Topology and Bus Topology to construct a tree like structure. The main structure of tree is in the form of a bus Backbone Cable. Each branch contains Star Network. So, the main bus connects to one or more Switches or Buses. Each Switch or Bus further connects to one or more Network Nodes and Network Devices. It is really flexible approach to Computer Networks. You can easily add Network Devices to this network by simply extending the Star Network at each branch of tree. However, at certain times you may require adding Drop Lines for extension.

Tree Topology Examples in Real Life

This topology is very useful for your organizations if you have small departments and even sub-departments. Similarly, if you have a multi-floor team placements then it can be best choice for you. If you try to use the basic Star Network scheme then it will create many problems for you. This is because in such situations, it is not favorable to run cables from one floor to another one. It will cost you too much.

Similarly, you cannot adopt basic Bus Network. If you do so, you will require installation of sub Backbone Cables. However, it is not favorable. This will also demand multiple punctures in both main Backbone Cable as well as Sub Backbone Cables. Each type of Backbone Cable will require using terminator. In case you need to add some more Network Nodes in a sub-department or department, you need to puncture backbone cables at  multiple locations. This will affect the Network Performance.

So, you will look for using a strong Bus Backbone Cable to connect floors. Moreover, you will connect each sub-departmental and departmental Network Nodes to single Hub. This Hub will be placed inside the department or a sub-department. This type of arrangement is more cost effective and feasible. It is much more flexible, reliable and fault-tolerant in comparison with Basic Types of Network Topology. Using a simple Star Network or Bus Network will create many bottlenecks and problems for you. So, you can use the hybrid scheme for facilitating yourself.

Tree Topology Images

Look at the following Tree Topology Example Images. I am sure these will give you great idea about this Type of Network Topology. These are same scenarios that I have discussed in the above sections. In both of these images you will find two common things:

1. Bus Network Backbone Cable
2. Star Network Sub Network Sections

Features of Tree Topology

• It is highly reliable and fault-tolerant. Failure of one or more computers doesn`t affect the working of whole Computer Network.
• You can easily extend Network Tree Topology to add more and more computers. It can easily be done by extending Star Networks connected to the main Backbone Cable.
• Network Performance can be really good due to the usage of Switch or Intelligent Hub.
• Tree Topology provides high security. This security is more enhanced when you use Intelligent Hub.
• For your small sized LAN Tree Topology is really a good option.

Applications and Uses of Tree Topology

Although it is not very common to use it. So, you normally don`t find its applications. However, its use entirely depends upon you. You can not only use it but can also get benefited from it. Quite often we consider Zigbee as an Application of Tree Topology. But let me tell you the fact that Zigbee doesn`t use Tree Topology. Instead, it is based on the concept of Mesh Network Topology. As far as its use is concerned you can use it anywhere.

• If you have a multi-story building and you want define clusters of Network at each portion then you can use it.
• Majority of offices are sub-divided into departments and sub-departments. So, you can segregate whole Tree Network by using multiple Switches. This makes the whole Network Tree more manageable and easy to maintain.

Tree Topology Diagram and Explanation

In this section, I will be explaining exact Tree Topology Meaning and I will do it with the help of a typical Picture Diagram of Tree Topology. This diagrammatic example considers a really simple Tree Network. This example Network contains a main Backbone Cable. You can clearly see that each end of this Backbone Cable has a Terminator. Moreover, Backbone Cable has three Drop Lines. These Drop Lines connect to a Server and two Switches. 

Switch on the left side connects to three Nodes. Two of Nodes are using Microsoft Windows while the third one uses Linux. So, this forms a Sub Network. When you look at the Sub Network on the right hand side then it looks a little different. Backbone Cable directly connects to a Hub/Switch. This Hub/Switch, in turn, connects to three Nodes and an additional Hub. This creates an Extended Star Topology. Each Hub/Switch in this Extended Star Network contains have three Nodes. Two of Nodes at each Hub are using Microsoft Windows while one uses Linux. We can say that Nodes in this Computer Network are quite heterogeneous in terms of platform.

How Tree Topology Network Works?

Answer to this question is really simple. I am sure that you will be able to understand it easily if you carefully see the above Image of Tree Topology. Suppose that Server wants to communicate with Node I. Server will encapsulate data message and the destination address. After this encapsulation, it will transmit the signal on Backbone Cable. Encapsulated package will move towards both branches of the Bus Backbone Network.

There are a variety of Types of Hub that you can use in your Tree Network. You may use 1) Active Hub 2) Passive Hub or 3) Intelligent Hub. Each of this one has its own working mechanism.  For the sake of convenience, I will discuss only the working theme of an Intelligent Hub here. So, let us assume that all the Hubs are actually Intelligent i.e. Switch. First of all, the packet will reach the Switch S1. S1 will check the destination address. Now clearly destination address doesn`t belong to this portion. So, it will automatically discard the package. For understanding working of this Network Topology carefully see above Picture of Tree Topology.

In the mean time, whole encapsulated packet will Switch S2. S2 will check the destination address and knows that it doesn`t have the required address. So, it will forward the package to Switch S3. S3 will then find link connecting the destination address I. It will send the package to specified destination.

Read More About: How Star Topology Works?

Types of Tree Topology

I think you people might have understood the concept of Tree Topology in detail. Now I am going to discuss different Types of Tree Network. Although there are no specialized types. But its important that you people get knowledge about these also. It will surely help you in your career as Network Engineer.

Bus Tree Topology

This type contains a main Backbone Cable. This cable is responsible for communication within whole Tree Network. Further, you connect computers to central devices like Hub or Switch. Instead of connecting to computer individually, Bus Backbone connects to central devices. But if you want to connect computers directly with Backbone Cable then you can. There is absolutely no restriction in it. Honestly speaking, whatever I have discussed so far belongs to this Type of Tree Network Topology.

Cluster Tree Topology

In Cluster Tree Topology, parent child relationship is the key concept in this type. Now how can you visualize a parent child relationship? Its really easy and simple. For the sake of simplicity you can say that a central device (Hub or  Switch) is simply the parent. If you ask me why then my answer is that each computer connects to the Bus Network Backbone through these central devices. So, a complete parent-child set is referred to as a cluster.  You may have a Server as a parent. But in most of the cases, central device is mostly designated as a parent. Each cluster is identified by cluster identification number.

Spanning Tree Topology

This is one of the widely used terminology. We quite often use it in graph theory. In any graph, we have two things 1) Nodes or Points 2) Edges or Connections. Spanning Tree is a tree that connects all the nodes of a graph. In other words, Spanning Tree is a sub-graph of a graph that contains edges for connecting all the nodes of a graph. Another allied term that is commonly used is Minimal Spanning Tree (MST). This provides us with a Spanning Tree costing us least to connect all the graph edges.

Spanning Tree Topology contains multiple Backbone Cables for connecting various clusters present in the whole Computer Network. If we are to minimize communication cost and overheads, we can even apply Minimal Spanning Tree Algorithm for this purpose.

Tree Topology Advantages and Disadvantages

Pros

Advantages of Tree Topology

• It is highly flexible and scalable. Unlike Bus Topology you don`t need to puncture the main backbone cable for adding computers. You can simply attach new computers to hub or switch. Even if less space is available, you can extend the Star Network for creating more space.
• Tree Topology is very much reliable. Failure of one or more computers doesn`t affect Network operations. Even in the event of failure of a single Switch/Hub, Network can still continue to operate.
• Due to the use of Intelligent Hub/Switch, Tree Topology provides a much better performance as compared to simple Bus Network.
• Establishment and management of this Network is really similar to Star Network.
• Problem discovery and troubleshooting is easy and straight forward.
• Tree Topology is really suitable for small sized organizations.
• You can get an enhanced security by adopting this scheme.

Cons

Disadvantage of Tree Topology

• It is more costly as compared to both Bus and Star Networks. This is because you require the equipment required for both Bus Topology and Star Topology.
• Huge amount of Network Cabling is required. Management and placement of large number of cables is really difficult.
• In case of any problem in central backbone cable whole Network stops working. In such a case, problem discovery and troubleshooting is really difficult.
• You should take great care of the Terminator at each end because any problem in the terminator can cause signal reflection.
• Using Tree Topology for large sized organizations is not recommended.

FAQs

1. What do you mean by Tree Topology?

It is formed by combining Bus Topology and Star Topology. A strong network backbone cable connects various sub portions of a Computer Network. Each part of Network can have one or more Network Nodes or Computers. Each computer inside a portion connects to a central device. This central device can be Hub or Switch.

2. What is the use of Tree Topology?

It is normally used in an environment where you want to segregate whole of your Computer Network into sub portions. You may have different office floors and you may want to segregate the management of each floor separately. Similarly, you may have different departments at a single floor. In such a situation, you may require a certain amount of decentralization in management of network.

3. What is a Tree Topology and its advantages and disadvantages?

Tree Topology is a hybrid of Bus Topology and Star Topology. It is mostly suited for small sized computer networks. It is highly flexible and reliable in its operations. Basic building block of this type of network topology is basically backbone cable of bus network. Whole network is organized around multiple sub-networks. Each sub-network contains multiple computers connected to central hub or switch.

Advantages

• It is highly flexible, reliable, scalable and secure.
• Performance is really good as compared to simple bus topology network.
• Network establishment, management, error detection and troubleshooting is a lot easier.

Disadvantages

• Large amount of capital cost is required for building and extending tree network.
• A lot of cabling is required. Managing such a large number of cables is really challenging.
• In case of problem in backbone cable whole network stops functioning.

Final Words

Being a hybrid of basic Topology Types, it incorporates advantages and disadvantages of both. Although Tree Topology is highly flexible, secure and reliable. Yet it is not suitable for large-sized Computer Networks. But trust me if you want to separate the management and troubleshooting of Network in terms of departments/sub-departments/floors then this may prove to be the best choice for you. I hope that you people might have liked and understood what I have told you. There is still a lot to come. Stay Tuned……………