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Computing Fundamentals
Chapter 8: Networking
and Internet Basics
Computing Fundamentals
Chapter 8: Networking and
Internet Basics
• Learning Objectives:
• Identify communications networks in daily life
• Distinguish between types of networks
• Identify common types of network hardware
• Understand the Internet and choose a connection
method
• Troubleshoot common network and Internet
connectivity problems
Computing Fundamentals
Communication Networks
• Networking is everywhere, and many of our everyday
activities are enabled or assisted by computer
networking.
• Large-scale networks include:
 Public Telephone and Data Networks
 The Internet
 Private Digital Networks
 Satellite Data Networks
 Cell Phone Networks
Computing Fundamentals
Public Telephone and Data
Networks
• The first worldwide network ever created was the
telephone network, predating computers by many
decades.
• This network is an example of a circuit-switched
network.
• Creates Point to point connection between locations
• Communication channel stays open the whole time.
Computing Fundamentals
Public Telephone and Data
Networks
• The public telephone system—the whole of the
world’s circuit-switched telephone networks—is
known as the public-switched telephone network
(PSTN).
Computing Fundamentals
Date / Computer Networks
• In contrast, Computer networks are packetswitched which is:
• Communication channel does not remain open the
whole time
• Data is broken up at the sending end into small packets
and routed individually to the receiver
• Each packet may take a different route to the destination
Computing Fundamentals
Packet-Switched Network
Computing Fundamentals
The Internet
• A global packet-switched network created
cooperatively by multiple companies, governments,
and standards organizations.
• Not owned or maintained by any one company.
• Most companies and individuals don’t connect
directly to the Internet; instead, they connect to an
Internet service provider (ISP), which in turn
connects to the Internet.
Computing Fundamentals
The Internet
• Multiple standards organizations manage the
protocols (rules).
• The Internet uses various protocols that all
participating computers have standardized on, so
that services like the web, email, and instant
messaging work the same everywhere.
• Based on TCP/IP protocol stack:
• Common set of standards
• Use in most private networks too
• IP addressing identifies each device by a numeric value
Computing Fundamentals
Private Digital Networks
• Companies maintain their own high-speed
connections between locations
• Can be achieved by:
1. Leased lines from the phone company,
2. Running their own cables.
3. Using the Internet: Internet is the most cost-effective
method, but not the most reliable method.
• Connection can be affected by Internet traffic
problems and connections that other companies
control and maintain.
• Using the Internet is also not very secure.
Computing Fundamentals
Virtual Private Networking
• Virtual Private Networking (VPN): A method of
creating a secure, private communication tunnel
using a public communications channel such as the
Internet.
Computing Fundamentals
Satellite Data Networks
• A satellite is a transmitter/receiver unit that orbits the
Earth, more than 22k miles (36k kilometers) up.
• About 6,600 satellites have been launched. The latest
estimates are that 3,600 remain in orbit. Of those,
about 1,000 are operational.
• Satellites are in geosynchronous orbit, meaning that
their orbit is synchronized with the Earth’s orbit
• They do not appear to change in position compared to any
location on Earth.
• A satellite contains transponders, which are two-way
radios that communicate with stations on the ground.
Computing Fundamentals
Geosynchronous Orbit
Computing Fundamentals
Satellite Data Networks
• Satellite are also used are used to quickly send
information between two points on Earth that are
physically separated by a great distance.
• Satellites are also used for services like :
• Satellite radio and TV distribution
• Satellite Internet services to consumers
• Some Internet services also use satellites to provide
Internet access to areas where other high-speed
connections technologies are not available.
Computing Fundamentals
Cell Phone Networks
• Cellular telephone companies have their own data
networks, using a combination of satellites, cables,
and on-ground towers.
•
•
•
•
Calls connect to the tower closes to them
The tower then taps into the larger network
Cell networks (3G/4G) can access the Internet
You can tether (connect) a smartphone to a computer
and use the phone as a modem.
• Usually called: Hotspot / Internet Sharing.
Computing Fundamentals
Cell Phone Handover (Handoff)*
Computing Fundamentals
Ways of Classifying Networks
• There are several ways to classify computer
networks:
1.
2.
3.
4.
Geographical Range
Peer-to-Peer and Client/Server
Intranets and Extranets
Ethernet Technologies
Computing Fundamentals
Geographical Range
• One way to classify networks is according to the
geographical range that they cover.
• From a few feet within a single person’s office to a huge
area that covers multiple countries or even multiple
continents.
1. Personal area network (PAN): single user
2. Local area network (LAN): in the same building or
campus.
3. Metropolitan area network (MAN): in the same city /
across campuses
4. Wide area network (WAN): on the same planet
Computing Fundamentals
Geographical Range
Computing Fundamentals
Geographical Range
• A Personal Area Network (PAN) consists of devices that
directly connect to a single computer.
• You might connect your notebook PC to the
projector in the room.
• You might also form a PAN by connecting your
smartphone to your computer.
• A Local Area Network (LAN) is a network in which all
the devices are located within the same physical
location, such as a single building or a group of
adjacent buildings.
• For example: Home or Small Office Network.
Computing Fundamentals
Geographical Range
• Metropolitan Area Network (MAN): is a network that
spans an entire town or city or, as the name implies, a
metropolitan area that might span a major city and its
suburbs.
• Wide Area Network (WAN): is a geographically dispersed
network, usually consisting of at least two LANs connected
together by an external link.
• A WAN may include various architecture and
communications hardware from different providers.
• The Internet is a form of global WAN.
Computing Fundamentals
Peer to Peer Network (P2P)
• Another way to classify networks is to look at whether
or not a server is involved in their management.
• Peer-to-peer (P2P) Network: is network that consists
only of clients (no servers).
• Also called a workgroup.
• Each computer shares in the
administrative burden of
maintaining the network.
• Good for small groups
of computers
Computing Fundamentals
Client/Server Networks
• Client/Server Network: A network that contains one or
more servers One or more dedicated servers
• Server is a computer that is dedicated to providing
network and sharing services to the other computers
on the network
• Central management of
security and identities
• Good for large groups
of computers (>10)
• Example:
UoB Network
Computing Fundamentals
Intranets and Extranets
• Intranet: A secure network that only staff within the
company can access, and usually only on-site.
• Extranet: A secure network that is available to both
employees and outsiders.
• An extranet may be used by the company’s business
partners, contract employees, or authorized customers.
Computing Fundamentals
Ethernet
• Ethernet: The current dominant standard for local area
networking devices.
• Ethernet can technically be either wired or wireless,
but it is common to refer to only the wired type as
Ethernet.
• Wireless Ethernet is popularly called Wi-Fi.
Computing Fundamentals
Wireless Networking
• A wireless connects the two points via radio frequency
(RF), such as WiFi, WiMax, Bluetooth, or infrared.
• Two main uses:
• Endpoints of connectivity: laptops, smart phones.
• Relay between network segments when cable
connection is not practical.
Computing Fundamentals
Wi-Fi
• Wi-Fi (Wireless Fidelity* or Wireless Ethernet): A
means of connecting computers and other devices
wirelessly.
• Often referred to by its standard number: IEEE 802.11.
• There have been different versions of the Wi-Fi
standard since its original development. The most
popular ones are 802.11n and 802.11ac.
Computing Fundamentals
Bluetooth
• An inexpensive short-range networking technology
used for computer-to-device connections such as
computer-to-printer or phone-to-headset.
• Range limit of 20 feet (around 7 meters).
• Used to create personal area networks (PANs) by
pairing
Computing Fundamentals
Infrared
• Uses (invisible) light waves to beam information
between devices
• IrDA is the standard (Infrared Data Association)
• Older technology, mainly replaced by Bluetooth
• Still used in TV, Satellite Receivers and AC remote
controls.
Computing Fundamentals
Microwave
• Microwaves are high-frequency radio waves.
• Microwave Communication System A secure, point-topoint wireless networking technology that requires a
line of sight between the two points.
• Therefore the transmitters are often placed high up on
towers or buildings.
• The points can be miles apart (up to about 25
miles),but as long as there are no visible obstructions
between them, they can exchange data.
• Not used widely as before.
Computing Fundamentals
Microwave Towers and Antennas
Computing Fundamentals
Network Hardware
• Network connectivity requires both hardware and
software.
• The software portion is handled by the operating
system; all modern operating systems include
network support.
• There are multiple devices and hardware
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•
•
•
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Network Adapters
Switches and Hubs
Routers
Repeaters
Network Cables
Computing Fundamentals
Network Adapter
• Network Adapter: A hardware component that enables a
computer to connect to a network.
• Most desktop and notebook computers come with a wired
Ethernet adapter built in
• Notebook computers almost always include a built-in
wireless adapter.
• Network Interface Card (NIC): A network adapter that is
on an expansion card, rather than built into the
computer’s motherboard
• Can be built into motherboard.
• Each network adapter has a unique hardware address,
called a media access control (MAC) address.
Computing Fundamentals
Switches and Hubs
• A switch is a box that provides a central gathering point
for all the computers in an Ethernet LAN.
• Each computer’s network adapter connects to the switch,
either via a cable or wirelessly.
• A switch manages data traffic between devices
• Hub is the earlier version of a switch. It sends all traffic to
all ports and rely on each computer to ignore unwanted
data.
• A wireless switch is a also known as wireless access point
(WAP) or simply Access Point.
• Repeaters: A device that receives and retransmits a
network signal.
Computing Fundamentals
Switches and Hubs
8-port switch
multi-port switch
Wireless access point
Repeater / Range Extender
Computing Fundamentals
Router
• A router performs all the
same functions as a switch,
but it also has an added
bonus: It can direct traffic
into and out of the LAN.
• Is typically used to direct
traffic to/from an Internet
connection
• Can include wireless
connectivity or not.
Computing Fundamentals
Network cables
• Twisted-Pair Cable: Cable that transfers data via pairs
of copper wires that are twisted around each other to
reduce Electromagnetic Interference (EMI).
• Standard cables are unshielded twisted pair (UTP).
• Shielded-twisted pair (STP) contains this extra
lining, and is used in environments where EMI is a
problem
UTP
STP
Computing Fundamentals
Coaxial Cable
• Coaxial Cable (Coax): consists of a solid copper
core with an insulated sleeve around it.
• Connects cable TV service or satellite dish to broadband
modem
• Carries data through a single copper core
• Carries data faster than UTP but is more expensive
Computing Fundamentals
Fiber Optic Cable
• Carries data with light pulses
• Each fiber is about the width of a
human hair
• Each cable contains hundreds of fibers
• Often used as the backbone of a
network
• Expensive and difficult to install
• Fast, secure, and not subject to
EMI
Computing Fundamentals
Internet Structure
• Mesh of interconnected routers.
• This makes the Internet very fault-tolerant. If any
single router or server goes down, network traffic is
simply routed around the point of failure.
• Data may take any available path to its destination
Computing Fundamentals
Internet Speed
• Internet does not have a fixed speed. Data travels
through the Internet as fast as it can go on
whatever cable it travels through
• Throughput depends on the capabilities of the
segment the data is passing through.
• Backbone (main roads) of the internet are highspeed lines
• The Internet service that you subscribe to has two
speeds: a theoretical maximum and an actual
speed.
Computing Fundamentals
Factors that Affect Internet Speed
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•
•
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Internet traffic
Local traffic
Server issues
Throttling
Computing Fundamentals
Types of Internet Connections
• Dial-up
• One of the oldest and slowest form of consumer
Internet access.
• Ties up a phone line and uses a dial-up modem
• Tops out at around 44.8 Kbps (that is 0.04 Mbps approx.)
• Cable Internet
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•
•
•
Uses the cable TV cable
Uses a cable modem
Fast speed
Can be optionally shared throughout the home or
business
• Not offered in Bahrain and most gulf countries
Computing Fundamentals
Types of Internet Connections
• Digital Subscriber Line (DSL)
• Comes through telephone
landline cable
• Moderately fast speed
• Very High Bit Rate DSL (VDSL)
is faster version of DSL
• Satellite
•
•
•
•
Slower than cable or DSL
Available in places where other broadband is unavailable
Requires professional installation of satellite transmitter
Bandwidth may be throttled, suffers from significant latency
(delay)
Computing Fundamentals
Internet over Cell Phone
Networks
• Available anywhere 3G (H, H+) or 4G (LTE) cell
phone service is available
• Phone can be connected to a computer (tethered)
to provide the computer an Internet connection
• Can be expensive on a limited data plan; beware of
overages
Computing Fundamentals
Key Terms, Continued
• protocol stack
• protocol
• public-switched
telephone network
(PSTN)
• repeater
• RJ-11
• RJ-14
• RJ-45
• router
• satellite
• satellite Internet
• shielded twisted pair • virtual private
(STP)
networking (VPN)
• smartphone
• switch
• tether
• wide area network
(WAN)
• Wi-Fi
• Transmission Control • wireless access point
(WAP)
Protocol/
• Internet Protocol
(TCP/IP)
• twisted-pair cable
• unshielded twisted
pair (UTP)
Computing Fundamentals
Summary
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1 . List three types of wireless connection.
2 . How do a switch and a router differ?
3 . Explain the difference between STP and UTP cable.
4 . What kind of cable would you need for a 1000BaseT
network?
5 . What is TCP/IP?
6 . List four ways to connect to the Internet.
7 . List two things to try if your computer is connected
to a network but can’t access the
Internet.
8 . Why is satellite Internet not more popular?