1. Communication and Network
CS-101
Lecture 7
Communication and Network
Department of Computer Science
College of Arts and Science 1
Mr. Omer Salih

2. Network
Network: A network is a group of two or more computer systems linked together. There are many types of computer networks, including:
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3. Types of netwoks local-area networks (LANs) wide-area networks (WANs)
campus-area networks (CANs)
metropolitan-area networks (MANs)
home-area networks (HANs)
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4. local-area networks (LANs)
The computers are geographically close together (that is, in the same building).
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5. wide-area networks (WANs)
The computers are farther apart and are connected by telephone lines or radio waves.
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6. campus-area networks (CANs)
The computers are within a limited geographic area, such as a campus or military base.
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7. metropolitan-area networks (MANs)
A data network designed for a town or city.
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8. home-area networks (HANs)
A network contained within a user's home that connects a person's digital devices.
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9. Protocol and Architecture
protocol : The protocol defines a common set of rules and signals that computers on the network use to communicate.
architecture : Networks can be broadly classified as using either a peer-to-peer or client/server architecture.
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10. Connectivity
Connectivity: the ability to link to and communicate with other computer systems, electronic devices, software, or the Internet.
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11. Topology
Definition : A network topology describes the arrangement of systems on a computer network. It defines how the computers, or nodes, within the network are arranged and connected to each other.
1. Star Topology
2. Ring Topology
3. Bus Topology
4. Mesh Topology
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12. Star Topology All the nodes are connected to center device.
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13. Ring Topology Devices are connected to each other in ring form.
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14. Bus Topology
All computers are connected to common communication channel.
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15. Mesh Topology
All computers are interconnected.
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16. OSI model
The OSI, or Open System Interconnection, model defines a networking framework to implement protocols in seven layers.
Application layer
Presentation layer
Session layer
Transport layer
Network layer
Data Link layer
Physical layer
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17. OSI model diagram
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18. Network and Transmission media:
Network Media: it is sometimes referred to as networked media) refers to digital media mainly used in computer networks such as the Internet.
Transmission media: The means through which data is transformed from one place to another is called transmission or communication media. There are two categories of transmission media used in computer communications.
BOUNDED/GUIDED MEDIA
UNBOUNDED/UNGUIDED MEDIA
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19. Types of Transmission Media
Guided Media :
Unshielded Twisted Pair (UTP)
Shielded Twisted Pair
Coaxial Cable
Optical Fibre
Unguided Media :
Radio Transmission
Microwave
Satellite Communication
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20. Software support
Definition : After-sales service provided by a software publisher or vendor in solving software conflicts and usability problems, and in supplying updates and patches for bugs and security holes in the program.
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21. Networking hardware
Networking hardware typically refers to equipment facilitating the use of a computer network.
Examples: bridge, hub, routers, switch, modem etc……
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22. Bridge
A bridge device filters data traffic at a network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two segments.
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23. HUB
HUB - is a device for connecting multiple twisted pair or fiber optic Ethernet devices together and thus making them act as a single network segment.
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24. Routers
Routers are small physical devices that join multiple networks together.
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25. Switch
A network switch is a small hardware device that joins multiple computers together within one local area network (LAN).
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26. Modem
Definition : a combined device for modulation and demodulation, for example, between the digital data of a computer and the analogue signal of a telephone line.
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27. Session 9 End
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28. Thank you for your attention
Mr. Omer Salih
Lecturer : Aasd Abd Elrashid