Transcript File - MAJU SUPPORT

Chapter 7 Chapter 7, 8 & 9
Network Basics
Data Communications
Chapter 8
The Internet and the World Wide Web
E-mail and Other Internet Services
Chapter 9
Connecting to the Internet
Doing Business in the Online World
McGraw-Hill Technology Education
Chapter 9 Objectives
Discuss the components required for
successful communications
Identify various sending
and receiving devices
Explain the purpose of
communications software
Describe various types of lines for
communications over the telephone network
Describe uses of computer communications
Describe commonly used
communications devices
List advantages of using a network
Discuss different ways to set up
a home network
Differentiate among client/server,
peer-to-peer, and P2P networks
Identify various physical and wireless
transmission media
Describe the various network
communications standards
Next
Communications Over the Telephone Network
What is the public switched
telephone network (PSTN)?

Worldwide telephone system
that handles voice-oriented
telephone calls
Next
Voice Over IP
Communications Over the Telephone Network
What is a dial-up line?
 Temporary connection using telephone line for
communications


Costs no more than making regular call
Computers at any two locations can establish a connection using
modems and telephone network
Next
Communications Over the Telephone Network
What is a dedicated
line?
 Always-on connection
between two
communications
devices

Five types are ISDN line,
DSL, FTTP, T-carrier line,
and ATM
Next
Communications Devices
What are examples of communications
devices?
Common types are dial-up modems, ISDN and
DSL modems, cable modems, wireless modems,
network cards, wireless access points,
routers, and hubs
ISDN and DSL modems send and
receive data from ISDN and DSL lines
Next
Communications Devices
What is a dial-up modem?

A dial-up modem converts digital signals to analog signals and vice versa

Usually in the form of an adapter card
Next
Communications Devices
What are ISDN and DSL modems?
Communications devices that send and
receive digital ISDN and DSL signals
Usually external devices in which one
end connects to a telephone line and the other
end connects to a port on the system unit
Next
Communications Devices
What is a cable
modem?
 Sends and receives
data over cable
television network
 Much faster than
dial-up modem or
ISDN
 Sometimes called a
broadband modem
Next
Communications Devices
What is a wireless modem?
 Allows access to the
Web wirelessly from
a notebook
computer, a smart
phone, or other
mobile device
 Typically use the
same waves used by
cellular telephones
Next
Communications Devices
What is a network card?
 Adapter card, PC
Card, ExpressCard
module, USB
network adapter, or
flash card that
enables computer or
device to access
network
 Sometimes called
network interface
card (NIC)
Next
Communications Devices
What is a wireless access point?
 Central
communications
device that allows
computers and
devices to transfer
data wirelessly among
themselves or
wirelessly to a wired
network
Next
Communications Devices
What is a router?
 Connects computers and
transmits data to correct
destination on network
 Routers forward data on
Internet using fastest available
path
 Some routers have a built-in
hardware firewall
Next
Communications Devices
What is a hub or switch?
 Device that provides central
point for cables in network
Next
Home Networks
What is a home network?


Multiple computers
connected in home
Several types of home
networks



Ethernet — connect
computers via cable
Powerline cable —
use electrical lines in house
Phoneline — use
telephone lines
Next
Communications Channel
What is a communications channel?
 Transmission media on which data travels in
communications system
Transmission media
are materials or substances
capable of carrying one or more
signals
Bandwidth is amount of data
that can travel over a
communications channel
Next
Communications Channel
How is a request sent over
the Internet using a
communications channel?
Next
Physical Transmission Media
What is physical transmission
media?

Wire, cable,
and other tangible materials
used
to send communications
signals
Next
Physical Transmission Media
What are twisted-pair cable and coaxial cable?


Twisted-pair cable is used for telephone systems and network cabling
Coaxial cable is often used for cable television wiring
Next
Physical Transmission Media
What is fiber-optic cable?

Capable of carrying
significantly more
data at faster speeds
than wire cables

Less susceptible
to interference
(noise) and, therefore,
more secure
Smaller size (thinner
and lighter)

Next
Wireless Transmission Media
What is wireless transmission media?


Used when inconvenient, impractical, or impossible to install cables
Includes Bluetooth and IrDA
Next
Wireless Transmission Media
What are broadcast radio and cellular radio?
 Broadcast radio
distributes radio
signals over long
and short distances
 Cellular radio
is form of
broadcast radio
used for mobile
communications
Next
Wireless Transmission Media
What is a microwave station?
 Earth-based
reflective
dish used for
microwave
communications
 Must transmit in
straight line with
no obstructions
Next
Wireless Transmission Media
What is a communications satellite?

Space station
that receives microwave
signals from earth-based
station, amplifies
signals, and broadcasts
signals back to any
number of earth-based
stations
Next
Network Hardware
• Network interface cards
– Network adapter
– Connects node to the media
– Unique Machine Access Code (MAC)
Network Hardware
• Network linking devices
– Connect nodes in the network
– Cable runs from node to device
– Crossover cable connects two computers
Network Hardware
• Hubs
– Center of a star network
– All nodes receive transmitted packets
– Slow and insecure
Network Hardware
• Switches
– Replacement for hubs
– Only intended node receives transmission
– Fast and secure
Network Hardware
• Bridge
– Connects two or more LANs together
– Packets sent to remote LAN cross
• Other packets do not cross
– Segments the network on MAC addresses
Network Hardware
• Router
– Connects two or more LANs together
– Packets sent to remote LAN cross
– Network is segmented by IP address
– Connect internal networks to the Internet
– Need configured before installation
Network Hardware
• Gateway
– Connects two dissimilar networks
– Connects coax to twisted pair
– Most gateways contained in other devices
Network Cabling
• Cabling specifications
– Bandwidth measures cable speed
• Typically measured in Mbps
– Maximum cable length
– Connector describes the type of plug
Network Cabling
• Ethernet
– Very popular cabling technology
– 10 Base T, 10Base2, 10Base5
– Maximum bandwidth 10 Mbps
– Maximum distances100 to 500 meters
Network Cabling
• Fast Ethernet
– Newer version of Ethernet
– Bandwidth is 100 Mbps
– Uses Cat5 or greater cable
• Sometimes called 100Base T
– Requires a switch
Network Cabling
• Gigabit Ethernet
– High bandwidth version of Ethernet
– 1 to 10 Gbps
– Cat 5 or fiber optic cable
– Video applications
Network Cabling
• Token ring
– Uses shielded twisted pair cabling
– Bandwidth between 10 and 25 Mbps
– Uses a multiple access unit (MAU)
– Popular in manufacturing and finance
Network Protocols
• Language of the network
– Rules of communication
– Error resolution
– Defines collision and collision recovery
– Size of packet
– Naming rules for computers
Network Protocols
• TCP/IP
– Transmission Control Protocol/Internet
Protocol
– Most popular protocol
– Machines assigned a name of 4 numbers
• IP address
• 209.8.166.179 is the White House’s web site
– Dynamic Host Configuration Protocol
• Simplifies assignment of IP addresses
– Required for Internet access
Network Protocols
• IPX/SPX
– Internet Packet Exchange/Sequenced
Packet Exchange
– Older protocol
– Associated with Novell Netware
– Replaced by TCP/IP
Network Protocols
• NetBEUI
– Network BIOS Extended User Interface
– Used by Windows to name computers
– Transmission details handled by TCP/IP
Network Protocols
• Token ring
– Nodes communicate when they have the
token
– Popular in manufacturing and finance
Modem Communications
• Plain Old Telephone System (POTS)
– Standard phone line
– Two-way voice communication
– Uses analog transmission techniques
– Data communication is slow
Modem Communications
• Modems
– Modulator/Demodulator
• Modulator converts digital to analog
– Speed measured in bits per second (bps)
• Current fastest speed is 56 Kbps
• Quality of phone lines dictates speed
– V.92 is the current modem standard
– Several modem types
•
•
•
•
Internal
External
Voice
Fax
Modem Communications
• Modem uses
– Connection to the Internet
– File transfer
• Uploading
• Downloading
Digital Data Connections
• Digital phone lines
– Local telephone companies are upgrading
– Service will faster and more reliable
– New phones will be needed
– Modems will need to be upgraded
Digital Data Connections
• Broadband connection
– Any data connection faster than 56 Kbps
– Common in business
– Becoming popular in home installations
Digital Data Connections
• ISDN lines
– Integrated Services Digital Network
– Basic rate uses three channels
• Two data channels each support 64 Kbps
• Error correction channel
– Primary rate uses 24 data channels
ISDN Connection
Digital Data Connections
• T lines
– High-capacity voice/data lines
– Used to control phone and data
– Several variants
– T1 transmits at 1.544 Mbps
– T3 transmits at 44.736 Mbps
Digital Data Connections
• DSL technologies
– Digital Subscriber Line
– Popular with home users
– Speeds range from 100 Kbps to 30 Mbps
– Asymmetrical DSL (ADSL)
• Upload speed slower than download speed
– Symmetrical DSL (SDSL)
– Requires a DSL modem
Digital Data Connections
• Cable modem connections
– Popular with home and office users
– Speeds between 1 and 3 Mbps
– Requires a cable modem
Digital Data Connections
• ATM
– Asynchronous Transfer Mode
– Efficient transfer of video and sound
– Requires a special NIC and hardware
Consumer E-Commerce
• Online shopping
– Purchasing through a web site
– Also called Business to Consumer (B2C)
– List of products is nearly endless
– Features
• Searchable catalog
• Secure checkout
• Customer support page
Consumer E-Commerce
• Online stores versus brick and mortar
– Brick and mortar implies a physical store
– Brick and mortar properties
• Limited hours
• Salespeople can offer assistance
• Customers can handle the merchandise
– Online store properties
• Store is open 24 x 7
• Salespeople usually not available
• Can only view the merchandise
Online vs. Brick and Mortar
Online store catalog
Brick and mortar store experience
Consumer E-Commerce
• Using online catalogs
– Good online stores have a catalog
– Products are often arranged by category
– Products can be found by keyword
Consumer E-Commerce
• Paying for purchases
– Vendors accept several payment methods
• Credit cards
• Paypal
• Electronic Fund Transfer
– May need to create an account
• Simplifies shipping
• Encourages repeat shopping
Consumer E-Commerce
• Getting customer service
– Needed to resolve problems
– Understand the policies before ordering
– Contact information
• How you contact the vendor
– Return policies
• Availability and fee for returning items
– Shipping policies
– Charges and fees
• Convenience fees
Consumer E-Commerce
• Online banking
– Most teller services handled online
– Balances can be obtained
– Bills can be paid
– Access is typically very secure
– Not available at all banks
Consumer E-Commerce
• Online finance
– Broker and investment services
– Costs less than a traditional broker
– Stocks and bonds can be traded
– Loans can be procured
– Tax returns can be filed
Business E-Commerce
• Business to business (B2B)
– Business transaction between companies
– Accounts for the majority of e-commerce
– Initially private networks were used
– Common transactions
• Reorder inventory
• Purchase stocks
• Credit checks
Business E-Commerce
• Intranets and extranets
– Business partners must work together
• Networks must work together
– Intranet uses Internet technologies
• Only internal workers can access resources
• Use a standard browser to access resources
– Extranets open the Intranet to clients
• Clients have password level access
• Allows the same abilities as employees
– Very simple to use and setup
Business E-Commerce
• Telecommuters
– Employee working outside of the office
– Connects to the office through technology
– Several technologies are used
• Home computer and the Internet
• Key card changes passwords often
• Encryption is used to protect data
Security
• Improved security measures
– Before 1998, Web security was nonexistent
– Now safer than restaurant purchases
– All reputable sites protect their customers
Security
• Secure web pages
– Allows safe transmission of credit card
– Use the secure socket layer (SSL)
• Encrypts data transmission to the server
– Secure pages are easily identified
• URL uses https://
• Browser status bar shows a closed lock