NETWORK TOPOLOGY

The Concept Of Network Topology

Definition Of Network

•  A network is a collection of computers and devices connected together via communications devices and transmission media.

Definition Of Topology

• A network is a collection of computers and devices connected together via communications devices and transmission media.
• It refers to both the physical and logical layout of a network.

Definition Of Network Topology : A network topology refers to the layout of the computers and devices in a communication network. 

Topology can be divided in two types: 

• Physical Topology
• Logical Topology

Physical Topology : A network refers to the configuration of cables, computers, and other peripherals.

Logical Topology : The method used to pass information between workstations on a network.

Types Of Network Topology

• Star Topology
• Bus Topology
• Ring Topology

Star Topology

Star Topology refers to all the computers and other nodes on the network that connects to a central device thus forming a star. 

In this configuration, every node connects to a central network device, like hub, switch or computer. The central network device acts as a server and the peripherals devices act as clients

Advantages Of Star Topology

• Centralized Management of the network, through the use of the central computer, hub or switch.
• Easy to add another computer to the network.
• If one computer on the network fails, the rest of the network continues to function normally.

Disadvantages Of Star Topology

• Can have higher cost to implement, especially when using a switch or router as the central network device
• The central network device determines the performance and number of nodes the network can handle.
• If the central computer, hub or switch fails, the entire network goes down and all computers are disconnected from the network.

Bus Topology

A bus network that consists of a single central cable ( back bone ) to which all computers and other nodes connect.

Single central cable (back bone) which connects all nodes on network using T-connector.

Signals are send as electrical pulse that travels along the cable to all nodes and only recipient accepts data. 

Advantages Of Bus Topology

• It works well when you have a small network
• Easiest network topology for connecting computers or peripherals in linear fashion.
• Requires less cable length than Star Topology.

Disadvantages Of Bus Topology

• Difficult to identify the problems if the whole network goes down
• It can be hard to troubleshoot individual device issues
• Not great for large networks
• Terminators are required for both ends of the main cable
• Additional devices slow the network down
• If a main cable is damaged, the network fails or spilts into two.

Ring Topology

On a ring network, a cable forms a closed loop with all computers and devices arranged along the ring.

In the past, the ring topology was the most commonly used in schools, offices, and smaller buildings where networks were smaller. However, today, the ring topology is seldom used, having been switched to another type of network topology to improved performance, stability, or support.

Advantages Of Ring Topology

• All data flows in one direction, reducing the chance of packet collisions.
• A network server is not needed to control network connectivity between each workstation
• Data can transfer between workstations at high speeds
• Additional workstations can be added without impacting performance of the network.

Disadvantages Of Ring Topology

• All data being transferred over the network must pass through each workstation on the network, which can make it slower than a star topology.
• The entire network will be impacted if one workstation shuts down.
• The hardware needed to connect each workstation to the network is more expensive than Ethernet cards and hubs/switches.