0. Basics of Computer Networking
Information Technology Department
Bryar Hassan (BSc & MSc Eng.)

1. Contents Computer Network Benefits of Computer Network
Types of Computer Network
Based on physical division
Based on coverage area
Based on topology
Computer Network Hardware
Types of Communication Media
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2. Computer Networks
Computer Network is a group of computers which are connected on each other
Formed to build efficiency and effectiveness
Contained by sever and client computers
Server is also the gateway for the computer network through internet access
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3. Benefits Resources sharing High reliability Money saving
Communication facilities
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4. Types of Computer Networks
Physically is divided into two:
Wired network
Wireless
Based on coverage area:
LAN (Local Area Network)
MAN (Metropolitan Area Network)
WAN (Wide Area Network)
Internet
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5. Types of Computer Networks (Cont.)
Based on topology:
Bus topology
Star topology
Ring topology
Mesh topology
Hybrid topology
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6. LAN (Local Area Network)
Connecting ten meters inside a building
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7. MAN (Metropolitan Area Network)
It is used to for the connection among some buildings
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8. WAN (Wide Area Network)
Connecting some areas
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9. LAN Versus WAN
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10. The Internet Connecting the world globally
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11. Types of Computer Network
Based on topology: the physical layout of a network, i.e. wires and equipment
Choices affects
Network performance
Network size
Network collision detection
Types: Bus, Star, Ring, Mesh, and Hybrid
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12. Bus Topology Also called linear bus Advantages Disadvantages
Easy to setup
Small amount of wire
Disadvantages
Slow
Easy to crash
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13. Star Topology All nodes are connected to a hub
The most common topology
Advantages
Easy to setup
Disadvantages
One hub crashing down entire network
Uses lots of cable
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14. Ring Topology Nodes are connected in a circle Advantages Disadvantages
Time to send data is known
No data collision
Disadvantages
Slow
Lots of cable
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15. Mesh Topology All computer are connected together Advantages
Data will always be delivered
Reliable
No collision
Disadvantages
Hard to setup
Lots of cable
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16. Hybrid Topology
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17. Computer Network Hardware
Modem
Network Interface Card (NIC)
Hub
Switch
Router
Communication media
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18. Modem Converts digital signal to analogue and vice versa
Conversion from digital to analogue called modulation
Conversion from analogue to digital called demodulation
Measures in bits per second (bps)
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19. Network Interface Cards (NIC)
Ethernet Card/Network Adapters
Connects each computer to wiring in the network
Handles sending, receiving, and error checking of transmitted data
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20. Hubs Centres of a star network All nodes receive transmitted packets
Slow and insecure
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21. Switches Replacement for hubs Only intended note receives transmission
Fast
Secure
Keep track of MAC addresses
Intelligent device
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22. Routers Connects two or more LANs, WANs together
Packages sent to remote LAN cross
Connect internal networks to the Internet
Selection of best available path and path forwarding
Need configured before installation
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23. Types of Communication Media
Unshielded/Shielded Tw
Coaxial cables
Fiber optics
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24. Twisted Pair Cables
Two wires twisted around each other to reduce electrical interference
Inexpensive
Already in place for telephone systems
Most common LAN cable and telephone systems
Speeds range from 1 Mbps to 1,000 Mbps
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25. Twisted Pair Cables Unshielded Twisted Pair (UTP)
Ordinary telephone wire
Cheapest and easiest to install
Suffers from interference
Shielded Twisted Pair (STP)
Metal braid that reduces interference
More expensive
Harder to handle (thick, heavy)
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26. Twisted Pair Cables
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27. Coaxial Cable
A center conductor wire surrounded by layer of insulation and metallic sheath
Higher bandwidth and has less noise than twisted pair
Shielded from interference
Speed up to 10 Mbps
Television distribution
Antenna to TV and cable TV
Long distance telephone transmission
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28. Fibre Optic Used light instead of electricity to send data
Much higher bandwidth than coaxial cable
Very secure
Hard to work with
Speeds up to 100 Gbps
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29. References
Slideshare lecture notes, online. Available on:
Tanenbaum, Andrew S. Computer networks. Vol. 4. Englewood Cliffs (NY): Prentice-Hall, 1989.
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