Chapter Six

1
Chapter Six

• Networking and Telecommunication

2
Chapter Outline

• Network Basics
• Electronic Mail and Teleconferencing
  Interpersonal Computing
• Telecommunication TrendsMerging and Emerging
  Technologies

3
Linking Up Network Basics

• Basic Network Anatomy
• Networks Near and Far
• Communication Software
• The Network Advantage

4
Basic Network Anatomy

• A computer network is anycomputer system that
  linkstwo or more computers
• components in a network
• Hardware
• Software

5
The Network Interface

• A network interface card (NIC)
• Is needed to connect a computer directly to a
  network
• uses a port on the computer
• Controls the flow of data between the computers
  RAM and the network cable
• Handles any protocols

6
Communication á la ModemModulator-Demodulator

• A modem is used to connect a computer to a phone
  line
• The computercommunicateswith digital signals
• The telephone systemwas designed to transmit
  voice signals which are analog

7
Communication á la Modem

• A modem
• Converts the digital stream of information from a
  computer to an analog stream in order to send a
  message on the telephone network

8
Analog and Digital Signals
Modulation
Demodulation
9
Computer Networks

• There are two general types of computer networks

LAN(Local Area Network)
WAN(Wide Area Network)
10
LAN (Local Area Network)

• A LAN is a network in which the computers are
  physically close to each other
• LAN networks are usually set up to share
  peripherals, such as printers and network servers
• Each unit is a node

11
WAN (Wide Area Network)

• A WAN is a network in which the computers are a
  great distance from one another
• Connections are madevia telephone lines,
  satellites, and/ormicrowave relay towers
• Each network site is anode

12
WAN (Wide Area Network)

• WANs are often made up of LANs

13
CAnet3 Physical Links
14
Telecommunication Trends Merging and Emerging
Technologies

• DDS (digital data service)
• T1
• ISDN (integrated services digital network)
• ADSL (asymmetric digital subscriber)
• Cable modems

15
Show and Tell

• Long Haul
• (yellow) Thicknet with vampire tap
• (black) Fibre Optic (1gigabit/sec/strand)
• Short Haul
• (orange) fibre optic
• (blue)10BaseT-10Mbits/sec uses 2 pairs
• Up to 100Mbits/sec (10/100 Ethernet)

16
Communication Software

• Communication software includes
• Software that allows the hardware to interact
  with various networks
• A network operatingsystem (NOS) controls
  informationshared between adedicated server
  andclient machines

17
Client/Server Model
18
The Network Advantage

• Networks allow people to
• Share computer resources (hardware and software)
• Share data
• Work togetherin new ways

19
Electronic Mail and Teleconferencing
Interpersonal Computing

• Electronic mail
• Teleconferencing
• ICQ
• Discussion groups
• Chat rooms

20
Synchronous vs.Asynchronous Communication

• Synchronous communication
• Same time
• Different place
• Real time data
• Video,chat

21

• Asynchronous communication
• Different place
• Different time
• Stored messages
• Email, discussions

22
Getting data

• Bulletin Boards
• On-line Databases
• Commercial On-lineServices

23
Bulletin Board Systems

• A BBS is an on-line version of a bulletin board
  people post messages to others
• BBSs are divided by common interest(SIGspecial
  interest group)
• Most BBSs allow members
• to post messages and
• download or upload software
• (risky)

24
On-line Databases

• On-line databases include
• current stock market status
• legal briefs
• library resources
• medical references
• 80 of internet accesses
• use a database

25
Commercial On-line Services

• Members pay a fee for these services
• News
• Research
• Shopping
• Banking

• Games
• email
• BBS teleconferences

26
Rules of Thumb On-line Survival Tips

• If you dont have to be on-line, go offline
• Avoid peak hours
• (11-2 and 6-8)
• Dont be afraid to stop
• Use your bookmarks

27
Rules of Thumb On-line Survival Tips

• Protect your privacy
• Forms
• cookies
• Think about the source

28
Telecommunication Trends Merging and Emerging
Technologies

• Alternative Technologies
• wireless transmission
• Voice mail
• Video teleconferencing
• E-money
• Small devices with internet browsers
• Phones
• PDAs(personal data assistants)

29
Telecommunication Trends Merging and Emerging
Technologies

• Optical Networks
• Fiber optic cables are replacing copper wires
• Light waves are used to carry information
• Provide data rates over one billion bits per
  second
• Offer extremely lowerror rates