Chapter 3 Connecting to the World Copyright 2004 by Zongqing Zhou PhD Niagara University 31 Establishing a Standard Connection To connect to the Internet via telephone line you will need four basic things ID: 588792
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E-commerce and Information Technology in Hospitality and Tourism
Chapter 3Connecting to the World
Copyright 2004 by Zongqing Zhou, PhD
Niagara UniversitySlide2
3.1 Establishing a Standard Connection
To connect to the Internet via telephone line you will need four basic things:A computerA modem
An internet Service Provider
A browserSlide3
Figure 3.1
Analog data
Modulator
Analog transmission (public telephone network)
Analog transmission (public telephone network)
Digital data
Digital data
Digital transmitter
Modem
Digital transmission (Digital data lines or local area network)Slide4
Modem
Modem comes fromModulatorDemodulatorA modem is an electronic device for converting between digital data from a computer or an audio signal suitable for transmission over telephone lines.
The speed of data transmission is measured in bits per second, kilobits per second or in bauds.Slide5
Modem (cont.)
A modems most common speeds are28,80036,000
56,000
Modems
Internal
ExternalSlide6
ISP and OSP
The gatewaysISP (Internet Service Provider)OSP (Online Service Provider)Slide7
ISP and OSP
ISPOnce connected you are directly connected to the Internet; it has no control over what you can access on the Internet.Most important factors when choosing an ISP:
Local phone number
Other features
Speed
Features
Pricing
Reliability Slide8
ISP and OSP
OSPYou are connected to the Internet through OSP’s serverOSP tends to offer its own programs which are screened and filtered through your service provider.Slide9
Figure 3.2
Computer Modem ISP InternetSlide10
3.2 Alternative Connections
Broadband communications channels- high-speed internet access.ISDN (Integrated Services Digital Network)A system of digital phone connections allowing a single wire or optical fiber to carry voice, digital network services, and video. Intended to replace POTS (plain old telephone system)Slide11
3.2 Alternative ConnectionsCable modem
Most widely subscribedTypically faster than DSLTypically an external deviceSlide12
3.2 Alternative Connections
DSL (Digital Subscriber Line) *leading methodPlugs into the existing LANBest available method of connectionWireless
No physical connection
Mobility and adaptabilitySlide13
3.2 Alternative Connections
Bandwidth- the amount of data that can be sent through a given communications circuit per second.Slide14
Wireless Terms
WAP (Wireless Applications Protocol)- allowing device manufactures and service providers to be bale to talk to each other, so that digital content can be delivered to consumers through the air regardless of standard used.WML (Wireless Markup Language)- language used to specify content and user interface.Slide15
Wireless Terms
W-CDMA or I-Mode- allows one to view 256 color graphics and HTML on their phones.HDML (Handheld Device Markup Language)- uses its own gateway to provide access to the wireless Web.
XML (External Markup Language)-
markup symbols to describe the content of a page or file.Slide16
3.3 Networking: LAN and WAN
LAN- local area networkA high speed data communication network that connects computers and other terminals within a geographically limited area, typically within adjacent buildings or complexes.It is different from PANs (personal area networks) MANs (metropolitan area networks), or WANs (wide area networks).
LANs are typically faster than WANsSlide17
3.3 Networking: LAN and WANBenefits of using networks
Allows sharing of resources like printersEasy and fast information sharingShare softwareResponse to service request is faster and betterSlide18
3.3 Networking: LAN and WANEarly LANs were vendor specific and used different standards. Today there are two common wiring technologies for a LAN, Ethernet and Token Ring. Slide19
3.3 Networking: LAN and WANWireless technologies are starting to evolve and are convenient for Mobile computer users.
When using Ethernet the computers are usually wired to a hub or to a switch. This constitutes the physical transport mechanism. Slide20
3.3 Networking: LAN and WANLANs can be interlinked by connections to form a Wide area network. A router is used to make the connection between LANs.Slide21
3.3 Networking: LAN and WANWAN- wide area network
Typically the same as a LAN but covers more geographical area.Slide22
LAN Terms
Firewall- is a set of related software programs that protect the resources of a LAN or a private network from users from other networks.Four main LAN systems:EthernetToken Ring
Arcnet System
FDDISlide23
Figure 3.3
LAN Internet
Computer
Computer
Computer
Computer
Computer
Firewall
Computer
Internet
Location of a firewall, which guards against unauthorized access to a LAN or Internet.Slide24
Figure 3.4
A bus-typology Ethernet LAN
Computer
Computer
Computer
Computer
Server
BusSlide25
Figure 3.5
Ring
Computer
Computer
Computer
Computer
Computer
Server
A token ring LANSlide26
Figure 3.6
A wireless LAN with two access points.
Antenna
Workstation
File server
Access point 1
Access point 2
Workstation
Wired Ethernet LAN