11.6.1.2 describe the advantages and disadvantages of network topologies bus, ring, star, mesh
Network topology
Network topology is a way of connecting nodes to a communication network.
A network topology describes how all of the parts of a network are arranged and connected together. The topology includes the nodes (e.g. computers, printers) and the connecting lines. There are four main types of topology (or share) that you need to know:
Star topology
Description: Each computer is individually connected to central point that can be a file server or switch. The central point that is used is usually a switch. Best used in a larger organisation than a household if only because of the expensive.
Advantages:
- Very reliable – if one cable or device fails then all the others will continue to work;
- Simple to troubleshoot because failures are localised;
- Adding devices doesn't affect speed of perfomance until server capacity is reached;
- Easy to upgrade or expand elements independently;
- High performing as no data collisions can occur;
Disadvantages:
- Uses more cable than any other design;
- Uses additional hardware (switches/hubs) which adds again to the cost;
- If the switch or hub fails, the whole element of the network supported by it crashes;
- If the server goes down, the whole network collapses;
- Can require more technical know-how to set up.
Bus topology
Description: Each machine is connected to a long, single cable which acts as a backbone to link all the devices in a network. Each computer or server is connected to the single bus cable through a connector called a T-piece. A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable. Best used in small or temporary networks - can be a useful home network solution.
Advantages:
- Simple and cheapest to install;
- Requires less cable length than star topology;
- Good for a temporary work;
- Flexible because elements can be removed or added without messing with the rest of the network.
Disadvantages:
- If the bus (spine) fails, the whole network crashes;
- Perfomance is affected by load - the more devices attached, the slower it functions;
- Bus cables are limited in length and must be terminated properly to avoid reflection of signal, which can crash the system;
- Data has to 'queue' sometimes because the bus is busy with other demands.
Ring topology
Description: Network where every device has exactly two neighbours for communication. Ring topologies allow packets to travel only in one direction.
Advantages:
- 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:
- All data being transferred over the network must pass through each workstation on the network, which can make it slower than a star topology;
- If the main cable fails or any device is faulty then the whole network will fail.
Mesh topology
Description: In a mesh network topology, each of the network node, computer and other devices, are interconnected with one another.
Advantages:
- Data can be transmitted from different devices simultaneously. This topology can withstand high traffic;
- Even if one of the components fails there is always an alternative present. So data transfer doesn’t get affected;
- Expansion and modification in topology can be done without disrupting other nodes.
Disadvantages:
- There are high chances of redundancy in many of the network connections;
- Overall cost of this network is way too high as compared to other network topologies;
- Set-up and maintenance of this topology is very difficult. Even administration of the network is tough.
Source: http://www.bbc.co.uk/, http://www.ianswer4u.com, https://www.computerhope.com
Questions:
- Explain what is network topology.
- Name four network topologies.
- Explain advantages of each network topology.
- Discribe differencies between any two network topologies.
Exercises:
Ex. 1
Exam questions:
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