1. Intro To Computer Networks
Basics

2. Objectives Explain digital vs. analog communications
List types of cables
List network devices
Explain packet switching and circuit switching
Describe role of protocols
Describe various networks
Recount basics of Internet and Internet access
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3. Network-Basics
A communications network is a collection of computers and other devices that communicate to share data, hardware and software
In order to communicate, information must be transformed into the format the network uses
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4. Network-Basics
Computers use several coding schemes based on binary digits
ASCII
EBCDIC
Unicode
Binary numbers
When data is transmitted, it usually takes the form of an electromagnetic signal
On a communication network, your data may be converted into several different types of waves
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5. Network-Basics
Data can travel from one network device to another over a cable or through the air
A communications channel is a physical path or a frequency for a signal frequency
Networks use different types of cables
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6. Transmission Media Wired Network twisted-pair cables- phone
coaxial cable- TV
Fiber-optic cable is a bundle of extremely thin tubes of glass
Wireless Network
Microwaves provide another option for transporting data
Radio and microwave transmissions are bent around the surface of the earth to reach towers
Communications satellites play an important part in long-distance communications
A transponder on the satellite receives the signal, amplifies it, and retransmits the signal back to a ground station
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7. Network-Basics
Bandwidth is the transmission capacity of a communications channel
High-bandwidth communications systems, such as cable TV, are sometimes referred to as broadband
Systems with less capacity, such as the telephone system, are referred to as narrowband
The bandwidth of a digital channel is usually measured in bits per second (bps)
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8. Network Components
Each device that is connected to a network is referred to as a node
The term workstation usually refers to a personal computer connected to a local area network (LAN), it is also called a client
A modem is a device that converts signals from a computer into a signal that can travel over a wide area network
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9. Network Components
A network interface card (NIC) is the key hardware component for connecting a computer to a local area network.
small circuit board that sends data to and from workstation to network
A server refers to any computer on a LAN or the Internet that contains the software to manage and process files for other network nodes
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10. Network Components
A host computer usually refers to any computer that provides services to network users
A hub is a device that connects several nodes of a LAN
A router is a device that is connected to at least two networks and makes decisions about the best route for data
A gateway is a device that performs functions similar to a router
A repeater amplifies and regenerates signals so they can retain the strength to reach their destinations
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11. Protocols
Communications protocol refers to set of rules for transmitting data from one node to another
Protocols allow two devices to negotiate and agree on how data will be transmitted
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12. Network-Basics Simplex – signal travels in only one direction
Half duplex – signal travels in both directions, but only one direction at a time
Full duplex – signal travels in both directions at the same time
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13. Network Classifications
Internetwork – a network composed of many smaller networks
Intranet – uses TCP/IP protocols but owned by a private business and does not typically allow remote access
Extranet – similar to intranet except that it allows remote password-protected access
WAN – (wide area network) covers a large geographical area and may consist of smaller networks
LAN (local area network) – typically covers a very limited geographical area
11/11/2018
M. Eyadat