COMPUTER NETWORKS :
A computer network is a system of interconnected computers and peripheral devices. For example, it may connect computers, printers, scanners and cameras.
Using hardware and software, these interconnected computing devices can communicate with each other through defined rules of data communications. In a network, computers can exchange and share information and resources.
A computer network may operate on wired connections or wireless connections.
When two or more networks are linked or connected and are able to communicate with one another using suitable hardware and software, it is called an internetwork.
BENEFITS OF COMPUTER NETWORKS ;
1. Computer network can share devices
2. Can share data and information
3. Can share internet access
COMPUTER NETWORKS DEVICES :
3. NIC (Network Interface Card)
5. UTP cable (wired)
COMPUTER NETWORKS :
DIFFERENCE OF COMPUTER NETWORKS :
1. Cost : LAN - low
MAN - high
WAN - higher
2. Network Size : LAN - small
MAN - larger
WAN - largest
3. Speed : LAN - fastest
MAN - slower
WAN - slowest
4. Number of computers : LAN - smallest
MAN - large
WAN - largest
NETWORKS TOPOLOGY :
1. Star topology
A star topology consists of a central host which acts as the centre, and all nodes connect to the host. A star topology is also known as star network.
A star network must have a host which acts as the centre - can be a server, hub or router.
In a star network, every node will not connect to the neighbouring nodes.
Every node must connect to the host in order to communicate.
The host will control the flow of communication in the network.
Advantages of star topology :
a) It is easy to implement. You only add nodes to the host.If one of the nodes fails, the star network can still function as long as the host is working.
b) The failure of a node does not affect the entire LAN. If the host fails, the network will fail to function.
c) There are no disruptions to the network when connecting or removing devices.
d) The network can be extended by adding new devices to the host or nodes.
e) Troubleshooting is easy when the host fails. Simply repair or replace the host and the network will continue to function.
Disadvantages of star topology :
a) If the host fails, the entire LAN will be affected.
b) Network speed decreases when the number of nodes increases.
c) Troubleshooting is difficult when one of the nodes fails.
d) A host must be installed to control the network.
2. Ring topology
A ring topology consists of all computers and other devices that are connected in a loop. Ring topology is also known as a ring network.
Advantages of ring topology :
a) Troubleshooting is easy when one of the nodes fails.
b) Repair or remove the failing nodes and the network will continue to function.
Disadvantages of ring topology :
a) Implementation is difficult. Network administrator has to terminate the entire network to install a new node between existing nodes.
b) A failing node will affect the entire LAN. If one of the nodes fails, the network will fail to function.
c) Network speed decreases when the number of nodes increases.
3. Bus topology
ABus networks are very common in Local Area Networks (LAN). A bus network must have a common backbone (the central cable) to connect all devices. A bus topology is also known as a bus network.
Advantages of bus topology :
1. Easy implementation. New devices can be added to the backbone or to the existing nodes.
2. Failure of a node doesn't affect the entire LAN.
3. No disruptions to the network when connecting or removing devices.
4. Network can easily be extended, by adding new devices to the backbone or existing nodes.
Disadvantages of bus topology :
1. If the backbone fails, the entire bus network will be affected.
2. Network speed decreases when the number of nodes increases.
3. Troubleshooting is difficult when one of the nodes fails.