Network topology defination and its types

Network Topologies define the arrangements of computers taking part in the network. These should be properly planned and implemented because a good selection of topology can result in the proper and adequate use of resources while a mismanaged arrangement of computers can lead to inefficient use of resources, loss of data, and time.

Types of Topologies 

Bus Topology

Ring Topology

Star Topology

Tree Topology

Hybrid Topology

Mesh Topology

Bus Topology 

• Bus topology comprises stations or terminals that are connected to a single communication line.
• This single communication line is referred to as a bus. Information frames originating from a station are broadcast away from the station in both directions on the bus. 
• Each station on the bus interrogates the information frame destination address field for its address. 
• If the destination field does not match the station's address, the station discards the information frame back on to the bus. 
• If the destination address matches the station address matches the address, it accepts the information frame and processes the frame.

Characteristics of Bus Topology

• It consists of a single shared communication link or cable shared by all nodes in the network.
• This is the multipoint configuration.
• Medium Access Control is essential.
• An adequate signal to noise ratio should be maintained.
• Proper signal balancing is essential to reduce transmitter overloading.
• Signal balancing becomes increasingly difficult with an increase in the number of stations.
• Repeaters can be used be to boost the signal and increase the distance.

Advantages Of Bus Topology

• Simple installation.
• Failure of a node does not affect the network functioning.
• Cabling cost is less, as only one main cable is required.
• Expansion is easier.
• No concept of dependability on a central node, like in the case of star topology.

Disadvantages Of Bus Topology

• Network collapse on the failure of mainline.
• Troubleshooting is difficult.
• Sharing a single cable result in slower access time.
• Data collisions are frequent.
• The time to transfer information may be large because each node tests the information packet floating in the network.
• Failure of cables may result in serious implications on the network. Cable failure can be extremely difficult to locate on large bus networks.

Ring Topology

• In a ring topology, all the stations are arranged in a logical ring and each computer has a direct point-to-point link with two computers surrounding it.
• Each node in a ring acts as a repeater. It accepts the data from the neighboring node and checks whether the data is sent for it or not.
• If the data is sent for some other node, it passes the data packet to the next node on the ring.

Which topology has no shape?

A ring topology has no shape because it has no end and no starting point.

Characteristics of Ring Topology

• It is used in high-performance networks where large bandwidth is required.
• Transmission is unidirectional.
• There is no termination point, as there is no end to the ring.
• The data is transferred sequentially I.e bit by bit around the ring.
• The signal is passed along the ring in one direction from one station to another station until it reaches the destination.

Advantages of Ring Topology

• There is no dependency on a single node.
• It is suitable to set up a high-speed network using optical fibers.
• There are no data collisions.
• Data packets travel at greater speed.
• There is no master controller in the network, as every computer is given an equal chance to access media.
• A shorter length cable is needed in ring topology as compared to a star topology.
• Fault isolation is simplified.

Disadvantages of Ring Topology

• Failure of one node stops the working of the whole network.
• A break in the cable ring collapses the entire network.
• A control mechanism is required to determine who should start up the ring.
• Since the transmission is unidirectional, the time taken to reach the information at the desired location may belong.
• Troubleshooting is difficult.
• Adding or removing nodes disturbs the network activity.
• It requires high maintenance.
• The addition of a new node in the network increases communication delay.

Star Topology

• Star topology is the most common type of network topology that is used in homes and offices. 
• In star topology, there is a central connection point called the hub. 
• Each computer on a star network or only to the destination computer in a switched star network.
• Star networks are relatively easy to install and manage, but bottlenecks can occur because all data must pass through the hub.
• In a star network, the best is when there is a failure in the cable then only one computer might get affected and not the entire network.
• In a star network, the entire network is dependent on the hi. So if the entire networking then there could be a problem with the hub.

Which topology is best?

A Star Network Topology is best suited for smaller networks and works efficiently when there is a limited number of nodes.

Characteristics of Star Topology

• This topology has a central connection point called the HUB.
• Each node in the network has a dedicated point to point link to the hub.
• The hub can be active or passive.
• Active hub generates the electrical signal and sends it to all the computers connected to it, where a passive hub acts as a connection point and does not generate a signal.
• There is no direct link between nodes.
• Hub performs the routing function.

Advantages of Star Topology

• If a computer crashes, it does not affect the entire network.
• It involves a minimal number of cables.
• Insertion or removal of a node from the network has no optimal effect over other computers in the network.
• Insertion of a new node does not increase communication delay.
• Troubleshooting is easy.
• Expansion is easier.

Disadvantages of Star Topology

• The whole system is dependent on a central node, so it should be powerful and for that matter, it may be costly.
• If the central node fails the whole of the network may come down.
• Cabling cost is more as each node is connected individually to the hub.

Tree Topology

• Tree topology is an extension of star topology.
• It is suitable for networks having a hierarchical flow of data.
• This means the data travels level by level.
• In the tree topology, computers are connected like an inverted tree.
• The server or the host computer is connected at the top. Data can flow from top to bottom and bottom to top in level by level manner.

Characteristics of Tree Topology

• It is a variation of star topology.
• Nodes are connected to a central hub that controls the traffic of the network.
• It has a hierarchical flow of data example data travels level by level.

Advantages of Tree Topology

• There are no closed loops hence the failure of one branch does not affect the whole system.
• It allows the network to isolate and prioritize communications from different computers.
• The branches may be extended without any delay or stopping the transmission of information from other branches.

Disadvantages of Tree Topology

• In contrast to the bus topology, tree topology is a bit complex and costly.
• Only one workstation can transmit information at a time.
• If the central hub fails, the system breaks down.
• The cabling cost is more.

Mesh Topology

• In a mesh topology, each node is connected to more than one node of the system. 
• In this way, there exist multiple paths between two nodes of the network. In case of failure of one path, the other one can be used.
• The mesh topology is mainly used in networks spread in a wide geographical area spanning several kilometers.
•  This kind of topology is extremely costly to implement and maintain.

Characteristics of Mesh Topology

• Each node has a dedicated point to point link to every other node in the network.
• Multiple paths exist between two nodes.

Advantages of Mesh Topology

• Dedicated links eliminate the traffic congestion problem.
• It provides data security and privacy due to dedicated links.
• It is robust because the failure of anyone's computer does not bring down the entire network.
• It ensures faster transmission without delay.
• Point to point links makes fault diagnosis easy.

Disadvantages of Mesh Topology

• Mesh topology is a bit complex and costly.
• Installation and reconfiguration are difficult.
• Cabling cost is more.
• It requires high maintenance.
• Troubleshooting is difficult in a large network.

Hybrid Topology

• A combination of different topologies makes a Hybrid Topology or Hybrid Network.
• Different topologies have their benefits and drawbacks so a hybrid network provides a means to take the benefit of these topologies collectively.

Which topology is the fastest?

In star topology, data can be transfer fastest mode.

In this post discusses the network topology and its types. I hope you have learned from reading this post. If you like this post then share it with your friends and you can comment on any of your doubts and I will replay then at the earliest. 

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