Network Topology
A computer not connected to any other device is called a "standalone". The moment you connect at least two computers, they form a network.
All networks fall into two categories: Local Area Network (LAN) & Wide Area Network (WAN).
Local Area Network
Scope: Small area such as a single building, home, or office.
Purpose: To connect devices that are in close range.
Speed: Usually fast as distances are short.
Example: Home WiFi network.
Wide Area Network
Scope: Large geographical locations, can even be world-wide.
Purpose: To connect multiple LANs, often across cities and countries.
Speed: Overall slower than LANs due to longer distances and complex infrastructure.
Example: The internet.
Local Area Networks are usually owned by a single organization or person, where Wide Area Networks may involve multiple service providers.
Network Topologies
A topology refers to the structure of a network. It is like the map or layout of how different devices (like computers, printers, and phones) are connected in a network. It shows how they are linked together and how they communicate with each other. There are two main types of network topologies:
Bus topology: An arrangement where nodes are connected in a daisy chain by a single central communications channel.
Star topology: An arrangement where a central node provides a common connection point for all other nodes.
Bus Network Topology
In a bus network topology, all nodes are connected to a single backbone cable. Each end of the backbone is connected to either a terminator or a computer which stops signals from ‘bouncing back’. Also, data is sent in one direction at a time, and only one computer can successfully transmit data at any one time. Carrier Sense Multiple Access (CSMA/CD) technology is used to enable nodes to transmit on the same cable.
Cheap and easy to setup.
Backbone cable is the point of failure.
New devices can be easily added.
Limited cable length
Packets are sent through the shared backbone, allowing every client on the network to see packets that aren’t intended for them. This is a security problem.
The backbone is used for communication by multiple clients, introducing the risk of collisions.
Star Network Topology
In a star network topology, all devices are connected via a central node, which can be a or a .
Packets are sent directly to their recipient, over a cable that is connected only to the recipient. Other clients on the network cannot see packets that aren’t intended for them, therefore better security.
If the central hub/switch fails, all communication over the network will be stopped.
It is easy to add and remove clients to and from the network.
Expensive to setup due to large amount of cables required.
Each cable has just one device communicating over it, eliminating the possibility of collisions.
The failure of one cable does not affect the performance of the rest of the network.
Physical vs Logical Topology
A Physical topology of a network defines how devices are physically wired/connected. Whereas a logical topology defines how devices communicate long the physical topologies.
For example, a network wired in star topology can actually behave logically like a bus network by using a bus protocol and appropriate physical switching.
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