2002

Sharing Information and Resources

Through Networks

2002

TELECOMMUNICATIONS

Communicating Information

Via Electronic Means

Over Some Distance• Next Office

• Next Continent

*

2002

Atlanta

Chicago

MIS

Accounting

2002

PROTOCOL

Rules & Procedures

To Govern Transmission

Between Components

In A Network

-TCP/IP

-OSI

2002

ANALOG SIGNAL

• Continuous Waveform

• Passes Through System

• Voice Communications

*

2002

DIGITAL SIGNAL

• Discrete Waveform

• Two Discrete States:– 1-bit & 0-bit– On / Off Pulse

• Data Communication

*

2002

Modems

• Convert Digital data (computers) to Analog signal(voice)– Internal/ External

2002

Multiplexer / Concentrator

• Combines signals from several terminals to be carried over one communications channel

• High-speed line

• Frequency

• Time

2002

COMMUNICATION CHANNELS

Means By Which Data Are Transmitted:

• Twisted Pair (Copper Wires)

• Coaxial Cable: (Insulated Copper Wires)

• Fiber-optic Cable

• Wireless

2002

COMMUNICATIONS CHANNELS

• TRANSMISSION SPEED: Bits per Second (BPS) or Baud

• BANDWIDTH: Capacity of Channel; Difference between Highest & Lowest Frequencies– Baseband (voice) - single transmission only– Broadband - divides channel by time or

frequency for several transmissions at once

2002

Twisted Pair

• UTP - Unshielded Twisted Pair– Cat 3 ~ 10Mbps, Cat 5 ~ 100Mbps

• Copper Wire; electrical signal

• Baseband

• Analog or Digital signal

• Crosstalk

• Low cost, easy to install

2002

Coaxial Cable

• Shielded Copper Wire; electrical signal

• Faster, less noise

• Baseband and Broadband

• Not flexible

• More noise resistant

*

2002

FIBER OPTICS

• Super Clear Glass or Plastic Fiber Strands

• Laser generates light signal

• Difficult to tap

• Up To Ten Billion Bits Per Second

• Full Duplex, Broadband

*

SIGNALSIGNAL LASERLASER CABLECABLE PHOTOPHOTODETECTORDETECTOR SIGNALSIGNAL

2002

Wireless Transmission

• Microwave

• Satellite

• Cellular and PCS

• Infrared Light

2002

Radio Waves

• Line of sight

• Antenna to Antenna

• Save $ because don’t run cable

• Interference or Security concerns

• Good if mobile

• 1-10 MBPS

• WAP – Wireless Application Protocol

2002

SPEEDS & COST OF MEDIA MEDIUMMEDIUM SPEEDSPEED COSTCOST

TWISTED PAIRTWISTED PAIR 300 BPS - 10 MBPS300 BPS - 10 MBPS LOWLOW

MICROWAVEMICROWAVE 256 KBPS - 100 MBPS256 KBPS - 100 MBPS

SATELLITESATELLITE 256 KBPS - 100 MBPS256 KBPS - 100 MBPS

COAXIAL CABLECOAXIAL CABLE 56 KBPS - 200 MBPS56 KBPS - 200 MBPS

FIBER OPTICSFIBER OPTICS 56 KBPS - 10 GBPS56 KBPS - 10 GBPS HIGHHIGH BPS: BITS PER SECONDBPS: BITS PER SECOND KBPS: KILOBITS PER SECONDKBPS: KILOBITS PER SECOND MBPS: MEGABITS PER SECONDMBPS: MEGABITS PER SECOND GBPS: GIGABITS PER SECONDGBPS: GIGABITS PER SECOND

2002

Client/Server Networks

• Server - Stores Programs, Data; Determines Access to Network … for many users.

• Client - Desktop interface– Fat client - client has power on desktop to run

programs (PC)– Thin Client - all deployed from server

• Less $ to support• Always current• One interface, Training easier

2002

Computer Networks

Arts & SciencesLAN

RussLAN

Rike LANLAN

L1

L2L3

L4

Lake CampusLANs

WANInternet

WSU

Bac

kbon

e

2002

NETWORK TOPOLOGIES

HOSTHOST

USERUSER

USERUSER

USERUSER USERUSER

STAR

2002

NETWORK TOPOLOGIES

BUS

USERUSER

USERUSER

SServererver

PrinterPrinter

USERUSER

USERUSER

2002

NETWORK TOPOLOGIES

USERUSER

USERUSER

USERUSER

USERUSER

RING

2002

LOCAL NETWORKS

• LOCAL AREA NETWORK (LAN): – Limited Distance (less than 2000 foot radius)

– Can Share Expensive Hardware & Software• Printers

• Office Products

*

2002

Local Area NetworksServer based Network Peer-to-peer Network

SERVER

PC PC PC PC

PC PC PC

Client Client Client

Client Client

2002

Metropolitan Area Network

• Often called a MAN

• Within a Local Dialing Area

• Often within a city

• Uses a Common Carrier’s Lines

• Often divisions of same company that are not in close proximity to set up a LAN

2002

• Spread over a large geographical area

• Common Carrier– Pay for usage and share ‘lines’

– Telephone Lines– Fiber Optic Cables

– Microwaves– Satellites

Wide Area Networks

2002

Wide Area Network - Connection

• Switched or Dial-up– Temporary connection

• Dedicated or Leased Lines– 2 locations (private)– High volume user– Always available

• Value Added Network– 3rd party leased lines

2002

VALUE-ADDED NETWORK (VAN)

• Private; Multipath; Data Only

• 3rd Party Managed

• Used By Several Organizations

• Subscription Basis– Fee + Usage

*

2002

PACKET SWITCHING

• Breaks Data Blocks Into Small Packets (E.G.: 128 Bytes)

• Packets Routed By Most Economical Means

• Reassembled At Destination

• Used on Value Added Networks

*

2002

Wide Area NetworksSending Data on the Internet

DestinationComputer

ISP

Router

Router

RouterPackets

Packets

Packets

Packets

Packets

User’s PC

Packets

2002

Uses of Telecommunications

• Telecommuting

• Electronic Mail

• On-Line Information Services

• Teleconferencing

• Facsimile Transmissions

• Electronic Data Interchange AOL

CompuServe

MSN

2002

Electronic Data Interchange

• Computer to Computer exchange of business transactions– Orders– Bills

• Save $ and time

• Eliminate errors by entered only once

• EFT - Electronic Funds Transfer

2002

• Group Writing & Commenting

• Electronic Mail Distribution

• Scheduling Meetings

• Shared Files & Databases

• Electronic Meetings

*

GroupWare

2002

Teleconferencing

• Electronic meetings

• Less travel

• More can attend

• Less cost

• Videoconference

• Computer conference

2002

Wide Area Networks

ISP Link to the Internet

ISP

Parent’sPC

Regional Network Regional Network

Internet Backbone

College LAN

Student’s PC

2002

Connection Options• Cable - 4/10 Mbps, ~$40/mo (digital)

– Ethernet Card and Cable Modem+ ($200-300)

• DSL - 8 Mbps, ~$30-150/mo (digital)

– DSL Hub + Ethernet Card, Dedicated(3)

• T-1 Line -1.5 Mbps,~$1,000s,Dedicated, Digital

– (T-2~6.3Mbps; T-3~44Mbps; T-4~275Mbps)

• ISDN - 128 Kbps, $56-82/mo– Digital Service Unit+ ($200-300), Dial-up

• Phone-line modem - 56Kbps, ~$20/mo– Modem < $50, Dial-up, Analog

2002

The Internet

• Server address

• Domain name

• E-mail address

A Network of Networks

sales @ fareastfoods.com

Username

Server address

2002

The World Wide Web• Client/Server network

• Browser–Netscape

–Internet Explorer

• Hypertext markup language - HTML

2002

The World Wide Web• Web pages• Web site• Multimedia files• URLs

2002

The World Wide Web

• Default HTML file (Home)

• Electronic commerce

• Intranets

• Extranets

2002

INTRANET

• Internal Network• WWW Technology• Firewall: Security System to Prevent Invasion of

Private Networks• Need Password• Overcomes Computer Platform Differences• Often Installed On Existing Network

Infrastructure*

2002

EXTRANET

Private Internet Accessible To Select Outsiders - Need Password

Link Organization To

• Important Clients

• Business Partners

• Top Executives & Board Members*

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Copyright © 2001 by Harcourt, Inc.

All rights reserved.

Handling the Present:

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