1. Computer Concepts 7 t h E d i t i o n
Chapter 5: Internet and LAN Technology 1

2. Chapter 5 Internet and LAN Technology
Section A: Network Building Blocks
Computer Concepts 7th Edition Parsons/Oja

3. Chapter Preview After this chapter, you should be able to:
Diagram Shannon’s model of a communications network
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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4. Why is networking computers advantageous?
Sharing networked hardware and software can reduce costs
Sharing networked hardware can provide access to a wide range of services and specialized peripheral devices
Sharing data on a network is easy
Networks enable people to work together regardless of time and place
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5. Why is geographic scope important?
Personal Area Network
Local Area Network
Metropolitan Area Network
Wide Area Network
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6. Client/server – contains servers and clients
What is the difference between a client/server network and a peer-to-peer network?
Client/server – contains servers and clients
Peer-to-peer (P2P) – every computer is considered an equal
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7. How are devices on a network physically arranged?
Star Topology
Tree Topology
Ring Topology
Bus Topology
Mesh Topology
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8. Network Links: What connects the nodes of a network?
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 transmission
Wired network
Networks use different types of cables
Wireless network
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9. What are popular cabling options?
Today’s networks use twisted-pair cables
UTP (unshielded twisted pair)
STP (shielded twisted pair)
Looks similar to telephone cable
Has square plastic RJ-45 connector
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10. What are popular cabling options?
Another option is coaxial cable
Resembles cable-TV cable
Round, silver BNC or F-type connector
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11. How do signals travel over a network?
Fiber-optic cable is a bundle of extremely thin tubes of glass
Each optical fiber (tube) is thinner than a human hair
USB, serial, parallel, SCSI, and Firewire connections
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12. What are the options for wireless networks?
Data can also travel airways in form of RF signals sent and received by a transceiver
Microwaves provide another option for transporting data
Radio and microwave transmissions cannot be bent around the surface of the earth to reach far-flung 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 on earth
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13. How do signals travel over a network?
Infrared light can also carry data signals, but for short distances with a clear line of sight
Best for transmitting between notebook computers and a printer, or between a PDA and a desktop computer
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14. What’s bandwidth?
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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15. How does data travel over a network?
In 1948, Claude Shannon published an article that described a communication model
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16. How does data travel over a network?
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17. What is a protocol?
A communications protocol is a set of rules for efficiently transmitting data from one network node to another
The best-known protocol is probably TCP/IP
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18. What’s a packet?
When you transmit data, it is broken up into small pieces called packets
A packet is a parcel of data that is sent across a network
Has the address of its sender
Has the address of the destination
Has some data
When they reach the destination, they are put back together into original form
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19. How does a protocol initiate a transmission?
A synchronous protocol coordinates sending and receiving by using a clock signal
Asynchronous protocols require the transmitting computer to send a start bit that indicates the beginning of a packet
Handshaking
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20. How do protocols regulate the flow of data?
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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21. Chapter 5 Internet and LAN Technology
Section B: Local Area Networks
Computer Concepts 7th Edition Parsons/Oja

22. LAN Standards: What are LAN standards?
LAN technologies are standardized by the Institute of Electrical and Electronics Engineers
IEEE designation numbers help identify compatible network technologies
IEEE 802.3
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23. What is ARCnet?
ARCnet (Attached Resource Computer network) is one of the oldest, simplest, and least expensive LAN technologies
Original ARCnet standard supported transmission rates of 2.5 Mbps
Later versions supported 20 and 100 Mbps transmission rates
Permits mixed transmission media
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24. What is Token Ring technology?
A Token Ring network, defined by the IEEE standard, passes data around a ring topology using a signal called a “token” to control the flow of data
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25. What is the FDDI standard?
FDDI (Fiber Distributed Data Interconnect) offers 100 Mbps speeds over fiber-optic cables
Popular campus network technology
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26. How does Ethernet work?
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27. How does Ethernet work?
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28. How fast is an Ethernet network?
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29. What equipment is required for Ethernet installations?
An Ethernet card is a type of network interface card designed to support Ethernet protocols
A hub is used to connect more than two computers
Each network device requires one of the hub ports
You can add hubs using an uplink port
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30. What equipment is required for Ethernet installations?
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31. What is Wi-Fi? Wireless LANs are slower but eliminate unsightly wires
Signals can be disrupted by large metal objects, cell phones, pagers, and other wireless devices
Most popular is sometimes called WiFi for “wireless fidelity”
Range of up to 150 feet
Bluetooth
1 Mbps, range of 30 feet
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32. HomePNA and HomePNC Networks
HomePNA uses a special NIC and cable to connect each computer to a standard telephone wall jack
Network frequency is usually different from voice, so can use network at same time you place a call
You cannot make a call when dial-up Internet connection is active however
HomePLC uses special NIC to connect to standard electrical outlet, but power fluctuations can adversely affect signal
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34. LAN Installation: How do I set up a simple LAN?
First make sure every PC contains an Ethernet port
Next, attach each workstation to a hub
With all workstations connected, turn them on
Windows should automatically detect the Ethernet cards and establish a connection to the network
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36. How do I specify which resources can be shared by other workstations?
Each workstation can specify whether its files will be accessible to other workstations on the network
Drive mapping is Windows terminology for assigning a drive letter to a storage device that’s located on a different workstation
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37. How do I specify which resources can be shared by other workstations?
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38. Chapter 5 Internet and LAN Technology
Section C: Internet Technology
Computer Concepts 7th Edition Parsons/Oja

39. Background: How did the Internet get started?
The United States created ARPA (Advanced Research Projects Agency).
To help scientists communicate and share valuable computer resources
In response to the Soviet Union’s launch of Sputnik in 1957, the first artificial satellite
The ARPANET, created in 1969, connected computers at four universities
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40. How fast does data travel over the Internet?
Using Ping or Traceroute, you can discover how long data is in transit
On average, data within the US usually arrives at its destination ms (milliseconds) after it is sent
Overseas transmissions require a little more time
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41. How fast does data travel over the Internet?
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42. What kinds of network devices are part of an ISP?
An ISP operates network devices that handle the physical aspects of transmitting and receiving data from your computer
Many ISPs operate servers to handle incoming and outgoing mail for their subscribers and Web servers for subscriber Web sites
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43. What kinds of network devices are part of an ISP?
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44. Internet Protocols: Why odes the Internet use TCP/IP?
TCP/IP provides a standard that is fairly easy to implement, public, free, and extensible
The Internet is not owned, operated, or controlled by any single entity
TCP/IP is glue that holds the Internet together
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45. Is TCP/IP the only Internet Protocol?
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46. IP Addresses: Does the Internet use a special addressing scheme?
The IP part of TCP/IP defines the format for the addresses that identify computers on the Internet
These addresses are called IP addresses
An IP address is a series of numbers, such as
It is separated into four sections by periods
Each section’s number cannot exceed 255
Each address requires 32 bits (8 bits per section)
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47. Do I need a permanent IP address?
Static IP address – permanently assigned IP address
Dynamic IP address – temporarily assigned
ISPs need static IP addresses
Clients typically use dynamic IP addresses as the IP addressing scheme provides approximately only 4.3 billion unique addresses
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48. Domain Names: What’s a domain name?
People find it difficult to remember long strings of numbers, so host computers also have names called domain names
Domain name – “fully qualified domain name” (FQDN), usually typed in all lowercase
Key component of URLs and addresses
www. msu.edu/biologycatalog.htm - is the domain name
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49. How are domain names related to IP addresses?
Each name corresponds to an IP address
Domain name system – Huge database that houses the names and IP addresses
Domain name servers – Computers that house the database
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50. How do I get a domain name?
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51. Is a fee required to obtain a domain name?
You can register a domain name for a minimal annual fee ($10 - $50)
Some Internet entrepreneurs have registered high-profile domain names and resell them
stockmarket.com - $900,000
answers.com - $150,000
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52. Chapter 5 Internet and LAN Technology
Section D: Internet Access
Computer Concepts 7th Edition Parsons/Oja

53. How does a dial-up connection work?
While connected to your ISP, your call is routed through the telephone company’s local switch to the ISP
Local Switch
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54. How does a modem work? Modem – derived from modulate and demodulate
Modulation – changing characteristics of a signal (digital to analog)
Demodulation – changing signal back to original state (analog to digital)
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55. How fast is a modem?
Speed was measured as baud rate, number of times per second that a signal in a communications channel varies speeds
Today, measure in terms of bits per second
V.90 – theoretical maximum speed of 56 Kbps
Even with perfect connection, a 56 Kbps modem tops out at about 44 Kbps
Slightly faster speeds may be available with the new V.92 and V.44 modem standards
Downstream vs. upstream
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56. Cable Television Connections: How does a cable modem work?
Community antenna television – CATV
The satellite dish farm at which television broadcasts are received and retransmitted is referred to as the head-end
From the head-end, cabling system branches out and eventually reaches consumers’ homes
Topology is similar to computer network, and that is what is formed when you use cable TV as your ISP
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57. How can the cable TV system provide Internet access?
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58. Are television and data signals carried over the same cable?
Lowest-capacity coaxial cable has far greater capacity than POTS lines
Cable’s bandwidth is divided among 3 activities
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59. What’s the significance of becoming part of a “neighborhood network”?
An always-on connection is always connected
A hacker who discovers that your computer has a security weakness can easily find it again, and its high-speed access makes it a very desirable target
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60. What’s the significance of becoming part of a “neighborhood network”?
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61. Offers high-speed digital communications links for voice and data
DSL, ISDN, T1, and T3: What other options are available for high-speed Internet access?
Several services such as DSL, ISDN, T1, and T3 take advantage of full capacity of the telephone connections (normal dial-up services do not)
Offers high-speed digital communications links for voice and data
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62. What is DSL?
DSL (Digital Subscriber Line) is a high-speed, always-on, Internet access technology that runs over standard phone lines
Several versions exist – ADSL, SDSL, HDSL
xDSL – refers to entire group of DSL technologies
DSLAM (DSL Access Multiplexor) – interpret data signals
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63. Who uses T1 or T3 service? T1 – high-speed 1.544 Mbps digital network
Consists of 24 individual channels (64 Kbps for each)
Popular for businesses and ISPs T3
672 channels
Supports data rates of about 43 Mbps
Sometimes referred to as DS3 (Digital Service-3) lines
Provide many of the links on the Internet backbone
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64. How does satellite access work?
Direct satellite service (DSS) uses a geosynchronous or low-earth satellite to send television, voice, or computer data directly to a satellite dish
Two-way satellite service ships both upstream and downstream data through the satellite
Offers 500 Kbps downstream
40-60 Kbps upstream
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65. How does satellite access work?
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66. Chapter 5: Internet and LAN Technology66

67. Conclusion You should now be able to:
Diagram Shannon’s model of a communications network
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
Chapter 5: Internet and LAN Technology 67