1. Networks and the Internet
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Networks and the Internet
Innovative Training Works
Digital Literacy

2. Objectives Identify network fundamentals
Identify the benefits and risks of network computing
Identify the relationship between computer networks, other communication networks, and the Internet
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3. Introduction Today, millions of people are using the Internet
Conduct business, do research, or read the latest news
Download software and files, “shop” on-line, play computer games, or look for employment opportunities
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4. Introduction
Number of users has been continuously increasing to hundreds of millions over the past few years
What really is the Internet? How does it work? How did it start?
How can we benefit from the Internet?
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5. What is the Internet?
The Internet, or simply the Net, is a collection of computer networks that link millions of different computers around the world.
History of Internet
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6. Why Information Superhighway?
You can “travel” to any of the millions of computers that are hooked up to the Internet, computers that might be thousands of miles away.
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7. How does Internet work?
Data travels by being relayed from one computer on a network, to another computer in another network until it reaches its destination.
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8. What is a computer network?
A computer network is a group of connected computers that exchange information.
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9. What are Protocols?
Protocol is a standardized collection of rules and conventions so that computers can exchange information regardless of their type or brand.
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10. Networks can be categorized:
By Scale
By Functional Relationship
By Topology
By Technology used
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11. Types of Networks (By Scale)
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
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12. Local Area Network (LAN)
In LAN, computers are connected within a local area, such as an office, a home, or a school’s computer laboratory.
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13. Metropolitan Area Network (MAN)
MAN is a larger network than LAN. It usually covers several offices, buildings or schools, each with their own LAN but connected to one another in the same city or locale.
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14. Wide Area Network (WAN)
Computers in a WAN are much farther apart, such as in two different cities. This is used to connect Local Area Networks together over vast distances.
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15. Networks (By Functional Relationship)
Peer-to-Peer
All computers in the network relatively have the same function.
Client-Server
Specially designated computers called servers are used for specialized tasks in serving the needs of other user-computers (called clients) on the network.
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16. Networks (by Network Topology)
Topology refers to the layout or structure of the network in relation with the flow of data.
The most common types of topologies are:
Star
Linear Bus
Ring
Hybrid
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17. Star Topology The most commonly applied topology.
Uses a central device (hub) with cables extending in all directions.
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18. Linear Bus Topology
Uses one long cable (backbone) to which computers and other devices are attached.
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19. Ring Topology
Consists of several computers joined together to form a circle. Data moves from one computer to the next in one direction only.
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20. Hybrid Topology
Hybrid topology is a combination of different types of topology used in a network system to adapt to the different design of floors or rooms in a building.
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21. What is Ethernet?
Ethernet is a computer network technology used in a Local Area Network (LAN). It is one of the most widely implemented LAN standards.
A signal on the Ethernet cables reaches every attached node in the network, a correct destination “address” is important to reach the intended recipient.
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22. Network Interface Card
To connect to a network, the PC must have a Network Interface Card (NIC).
Wireless PC NIC
Internal PC NIC
(RJ45)
Internal PC NIC
(Coaxial)
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23. Connection/Cabling Options
Twisted Pair
Coaxial
Fiber Optics
Wireless
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24. Twisted Pair
This is one of the most widely used communications media because it is inexpensive and widely available.
Unshielded Twisted Pair (UTP)
UTP with RJ45 connectors
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25. Coaxial
This is a cable with a center wire surrounded with insulation; usually used in cable TV.
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26. Fiber optics
Instead of transmitting electrical frequencies, a fiber optic cable transmits pulsating beams of light. It is made up of glass or plastic fibers.
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27. Wireless
More and more people now use wireless networking, also called Wi-Fi, to connect their computers at home or in the office.
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28. The Hub Hubs are used to connect PCs together to form a network. Back
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29. The Switch
A switch works similar to a hub except that user connected to the switch has access to the full bandwidth.
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30. The Router
Routers examine the destination address of the information and pass it on to the appropriate segment(s) only.
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31. Hub, Switch, and Router
Hub
Switch
Router
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32. Sample LAN Diagram UTP Cable Ethernet Card Hub/Switch Back
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33. Benefits of Networking
Reduces costs (don’t have to buy printer for each computer, etc.)
More productivity (don’t have to transfer files by diskette, etc.)
Increases communication
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34. Disadvantages of Networking
Dependency
Security Risk
Loss of Autonomy or Privacy
Viruses
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35. Roles of Network Administrator
Managing the computer network
Making sure network is working properly
Responsible for network security
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36. Getting Connected to the Net
To connect your PC to the Internet, you must have the following basic requirements:
Internet Service Provider
Modem
Telephone Line
Internet Software (Web browser, , etc.
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37. Types of Internet Connection
Narrowband
Dial-up
ISDN
Broadband
DSL
Cable
Dedicated Leased Line (such as T1)
Wireless (Wi-Fi)
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38. The Modem
Modem converts digital signals to analog signals and vice-versa in a process called modulation-demodulation.
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39. Internet Service Providers
ISP is a company that provides you connectivity to the Internet.
Infocom
ISP Bonanza
MozCom
Pacific Internet
Sky Internet, etc.
Roles & Responsibilities of ISP
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40. Dial-up The most common type of connection for home users.
Considered the slowest but have the reputation of being the most inexpensive.
Connection rates for dial-up modems tend to fall at around 56 kbps.
You cannot use the telephone for the Internet and phone calls for the same time.
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41. Integrated Services Digital Network
ISDN is a type of digital telephone connection that offers data transfer rates of up to 128 kbps.
This can be a better than dial-up, however ISDN connections are considered still more or less outdated.
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42. Digital Subscriber Line (DSL)
Becoming widely available and can provide an excellent connection.
Allows you to use the phone normally while connected to the Internet.
DSL connections can be costlier than dial-up.
DSL operates starting at 512 Kbps
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43. Cable
Offers very fast and reliable connections with a fixed monthly fee.
It will not affect how you use your telephone.
Offers data transfer rates of approximately 1 mbps to 6 mbps.
Cable connections are not always available in all areas.
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44. Dedicated Leased Line
Directly connects your computer to your ISP’s network. Capable of transferring data at 1, 544, 000 bits-per-second, such as T1.
Upload and download speeds are the same (symmetric)
Much more expensive than cable or DSL connections.
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45. Wireless (Wi-Fi)
No cords or wires for as long as you are in a WiFi “hotzone”.
Wireless broadband connections: Wi-Fi, Satellite broadband, Wireless DSL, and Wireless Digital Cable.
Connection speeds ranging from as little as 256 Kbps to as much as 10+ Mbps.
You have to stay within a certain radius to connect to a WiFi device.
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46. Roles and Responsibilities of ISP
Maintain connection
Customer Support
Technical Support
Security
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47. How did it start?
In the 1960’s, there was a demand for computer networks to help scientists and researchers from widely dispersed areas.
US Defense Department created ARPANET (Advanced Research Projects Agency Network) in 1969
ARPANET became the forerunner of today’s Internet.
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48. Internet Services Electronic Mail (E-mail) World Wide Web (Web)
Search & File Sharing (Google)
Instant Messaging (IM)
Internet Relay Chat (Chat, IRC)
Newsgroups
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