Network Topologies

Computers can be connected together in many different ways. The layout/topology of the network will influence how reliable the network is and how easy it is to access. There are two types of topologies:Wired and Wireless. The main physical wired topologies are: Star, Ring, Bus and Mesh.

STAR TOPOLOGY

In a Star configured network, all devices are connected to a central device called a hub. Nodes communicate across the network by passing data through the hub.

Advantages:

  1. New stations can be added easily
  2. A single cable failure won’t bring down the network
  3. Relatively easy to troubleshoot

Disadvantages:

  1. Single point of failure – if hub goes down, the network goes down
  2. Total installation cost may be high due to the number of cables needed for each node

RING TOPOLOGY

All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. When a computer sends data, the data travels to each computer on the ring until it reaches it destination.

Advantages:

  • Growth of ring has minimal effect on performance
  • Each node is able to filter and amplify the data before sending it to the next node.
  • Can cover a larger area than star.

Disadvantages:

  • A break in the cable will shut down the network
  • Most expensive topology
  • One computer failure affects others
  • Difficult to add or remove stations

BUS TOPOLOGY

Image courtesy of networkgue.blogspot.com

Devices are connected to a single central cable called the bus or backbone. Using the BUS and destination address, data is transmitted from source to destination along the backbone.

Advantages:

  1. – Inexpensive and easy to install
  2. – You can add and subtract devices without affecting the network
  3. – Failure of one device does not affect the network
  4. – Requires less cabling than star

Disadvantages:

  1. Network shuts down if there is a break in the cable
  2. Terminators are needed at both ends of the cable
  3. Difficult to troubleshoot

MESH TOPOLOGY

Devices are connected with many redundant interconnections between nodes.

Advantages:

  1. Failure of one node doesn’t affect the network
  2. Easy to expand
  3. More secure

Disadvantages:

  1. Very expensive due to the number of cable that would be required
  2. Difficult to implement

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Networking – Types of Networks

There are several types of computer networks, but the main ones are:

  1. Local Area Network (LAN)
  2. Wide Area Network (WAN)
  3. Metropolitan Area Network (MAN)

Local Area Network (LAN) – these are computers and devices that are connected in small and limited area like a school, the office a lab etc. The data transfer rates are the lowest of the three networks mentioned.

 

 

 

 

 

 

 

Wide Area Network (WAN) – A WAN consists of several LANs connected together over the internet. WANs covers the largest geographical area of all networks.

Wide Area Network Image courtesy of bhumika.ca

Metropolitan Area Network (MAN) – MANs fall between the LAN and WAN. They cover a larger area than the LAN, but are much smaller than a WAN. As the name suggests, MANs covers cities.

MAN image courtesy of transition.com

Advantages of Networks

  1. Speed – transferring files is done quickly in networks
  2. Cost – less software and hardware need to be purchased
  3. Easy Management – Software are installed in a central location (the server), so updates can be dispatched easily through the server
  4. Resource Sharing – All machines in the network are connected to the same resource (printer, storage server)

Disadvantages of Networks

  1. If the server goes down, stored information on it becomes inaccessible
  2. Resources connected to the network becomes inaccessible
  3. Possible risk of attack from virus and hackers
  4. As traffic increases on a network, the performance degrades
  5. Larger networks become more difficult to manage