Network Topology

Network topologies describe the ways in which the elements of a network are mapped or interconnected. They describe the physical and logical arrangement of the network nodes.

​

Types of Topology

• Point to Point

• Bus

• Ring

• Star

• Tree

• Mesh

• Hybrid

​

Point -to-Point Topology

​

In Point – to – Point, two nodes are directly interconnected. In P-P link each node receives exactly from one node and transmit to each node directly. 

​

Bus Topology

The bus topology uses a common single cable to connect all the workstations. Each computer performs its task of sending messages without the help of the central server. However, only one workstation can transmit a message at a particular time in the bus topology. 

The transmission from any station travels the length of the bus in both directions, and can be receive by all other stations.

The bus has terminators at either end which absorb the signal, removing it from the bus. Data is transmitted in small blocks with destination address, known as packets.

​

Advantages of Bus Topology

• Easy to connect and install.

• Involves a low cost of installation time.

• Can be easily extended.

​

Disadvantages of Computer Network

• The entire network shuts down if there is a failure in the central cable.

• Only a single message can travel at a particular time.

• Difficult to troubleshoot an error.

​

Ring Topology

Nodes /  Workstations - The term nodes refer to the computers that are attached to a network and are seeking to share the resources.

Data is accepted from one of the neighbouring nodes and is transmitted onwards to another. Thus data travels in one direction only, from node to node around ring. After passing through each node, it returns to the sending node, which removes it.

 

Advantages of Ring Topology

• Short cable length.

• The data being transmitted between two nodes passes through all the intermediate nodes, so no amplifier required.

• A central server is not required for the management of this topology.

• No wiring closet space required.​

Disadvantages of Ring Topology

• Node failure causes network failure.

• Difficult to diagnose faults.

• Network reconfiguration is difficult. The movement or changes made to network nodes affects the performance of the entire network.

Star Topology

A Star topology is based on a central node which acts as a hub. It consists of a central node to which all other nodes are connected by a single path.

The most common example of this is 10Base-T Ethernet network installations. Each node is connected to a 10Base-T hub by means of twisted pair cable.

​

Advantages of Star Topology

• Due to its centralized nature, the topology offers simplicity of operation.

• It also achieves an isolation of each device in the network i.e. one device per connection.

• Simple access protocols.

​

Disadvantages of Star Topology

• Failure of the central hub leads to the failure of the entire network, i.e. central hub dependency.

• Long cable length.

• Difficult to expand.

​

Tree Topology

In a tree topology, stations are attached to a shared transmission medium. It is a variation of bus topology. The shape of the network is inverted Tree. The tree topology combines the characteristics of the linear bus and the star  topology. It consists of groups of star – configured workstations connected to a bus backbone cable.

​

Advantages of Tree Topology

• Eliminates network congestion.

• The network can be easily extended.

• Faulty nodes can easily be isolated from the rest of the network

​

Disadvantages of Tree Topology

• Uses large cable length.

• Requires a large amount of hardware components and hence is expensive.

• Installation and reconfiguration is very difficult.

​

Mesh Topology

Mesh topology is a group of nodes which are all connected to each other and many types of connections are possible in a mesh topology.

There are Two types of Mesh topology. 

(a) full mesh topology    (b) partially-connected mesh topology

​

In Full mesh topology , every node is connected with other nodes. There are n(n-1)/2 connections. (b) partially-connected mesh topology

​

In partially-connected mesh topology, at least two of the computers in the network have connections to multiple other computers in that network. If one of the primary computers or connections in the network fails, the rest of the network continues to operate normally.

Advantages of Mesh Topology

• Manages high amounts of traffic, because multiple devices can transmit data simultaneously.

• A failure of one device does not cause a break in the network or transmission of data.

• Adding additional devices does not disrupt data transmission between other devices.

​

Disadvantages of Mesh Topology

• The cost to implement is higher than other network topology, making it a less desirable option.

• Building and maintaining the topology is difficult and time consuming.

• The chance of redundant connections is high, which adds to the high costs and potential for reduced efficiency.

​

Hybrid Topology

Hybrid topology is a mixture of two or more topologies in a way that the resulting network does not exhibit one of the standard topology (e.g., star, bus, ring, etc.)

​

Advantages of Hybrid Topology

• Reliable.

• Effective

• It is flexible.

• It is Scalable.

​

Disadvantages of Hybrid Topology

• Complexity

• Expensive.

​

To Download PPT - Click Here Network Topology​