chapter 6 telecommunications, networks, and wireless computing 8.1 telecommunications, networks, and...

Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing

8.1

Telecommunications, Networks, and Wireless Computing

SESSION 8


8.2

TELECOMMUNICATIONS

• Telecommunications:Telecommunications: Communication Communication of all types of information, including of all types of information, including digital data, voice, fax, sound, and video digital data, voice, fax, sound, and video from one location to another over some from one location to another over some type of networktype of network

• Network:Network: A group of computers and A group of computers and associated peripheral devices connected associated peripheral devices connected by a communication channel of sharing by a communication channel of sharing information and other resources among information and other resources among usersusers


8.3

SENDER RECEIVERMEDIUM

Basic Communications Model


8.4

• Text

• Voice

• Image

• Video

Types of Data


8.5

Three Major Developments Shaping

Contemporary Systems

1. Client/server computing

2. Packet switching

3. TCP/IP and other communications standards

The Corporate Telecommunications System

Features of Contemporary Telecommunications Systems


8.6


A corporate telecommunications system

Figure 8-1


8.7

Client/Server Computing

• Powerful personal computers connect to network with one or more server computers

• Has extended networking to parts of business that could not be served by centralized architecture

• Processing load balanced over many smaller machines




8.8

Packet Switching

• Messages broken into “packets” before transmission

• Packets include destination and error-checking information

• Packets travel independently using routers; reassembled into original message at destination




8.9


Packet-switched networks and packet communications

Figure 8-2


8.10

Packet Switching• Packet switching breaks transmissions into packets

• When a packet arrives at a switch, the switch must decide where to send the packet next

Switch

Switch

A

BC

D E

Trunk Line


8.11

TCP/IPTransmission Control Protocol/Internet Protocol

• Open suite of protocols for connectivity developed in 1970s

• Provides standards for breaking messages into packets, routing them to destination addresses, and reassembling them at end

• Allows for communication regardless of hardware/software




8.12

TCP/IP: Four-Layer Reference Model1. Application layer: Communication between applications

and other layers

2. Transport layer: Acknowledging and sequencing packets to/from application

3. Internet layer: Addressing, routing, packaging data packets

4. Network interface layer: Placing packets on and receiving them from network medium




8.13


The Transmission Control Protocol/Internet Protocol (TCP/IP) reference model

Figure 8-3


8.14

Communication Media/Channels

Guided Media:Twisted PairCoaxial CableOptical Fiber

Unguided Media:MicrowaveSatelliteBroadcast Radio


8.15

Twisted Pair

Coaxial Cable

Optical Fiber

Guided Media


8.16

• Analogue signal: a continuous wave

• Digital: a discrete set of on (1) and off (0) electronic bursts rather than a continuous wave.

+1

0

0

11

0

Analog and digital signals


8.17


8.18

Microwave- “Line of sight” media:

antennas need to see each other

Unguided Media: Microwave


8.19

Unguided Media: Satellite


8.20


8.21

Transmission Speed• Bps: Bits per second• Baud rate: Rate of signal changes • One signal change = cycle• Transmission capacity is function of frequency• Bandwidth: Range of frequencies

accommodated on a particular channel


Transmission Media


8.22


Transmission Speed

Transmission Media

Twisted wire Up to 100 Mbps Low cost

Microwave Up to 200+ Mbps

Satellite Up to 200+ Mbps

Coaxial cable Up to 200 Mbps

Fiber-optic cable Up to 6+ Tbps High cost


8.23

By geographic span Local Area Network (LAN) Wide Area Network (WAN)

By topology (physical) Star Bus Ring Mesh

By architecture (logical) Peer to peer versus client-server Centralized versus distributed versus hybrid

Computer Networks


8.24

Network Topology: STAR


8.25

Network Topology: Bus


8.26

Network Topology: Ring


8.27

Communications Networks

Network topologies

Figure 8-8


8.28

Local Area NetworksLocal Area Networks

• Encompass a limited distanceEncompass a limited distance

• Require its own communication channels Require its own communication channels

• Support high volumes of data and functions Support high volumes of data and functions requiring high transmission speedrequiring high transmission speed

• Gateway, router, Network Operating System (NOS)Gateway, router, Network Operating System (NOS)

COMMUNICATIONS NETWORKS


8.29

A Local Area Network (LAN)



8.30

Wide Area Networks (WANs)Wide Area Networks (WANs)

• Span large geographical distanceSpan large geographical distance

• Consist of variety of switched and Consist of variety of switched and dedicated lines, satellite, and microwave dedicated lines, satellite, and microwave technologiestechnologies



8.31


8.32


8.33


8.34

• Use radio waves to connect stations• 802.11b: Current standard; 54 Mbps in 2.4 GHz

range• Infrastructure mode: Wireless devices

communicate with wired LAN via access points• Ad-hoc mode: Peer-to-peer mode; wireless

devices communicate with each other directly


Wireless Networks: Wi-Fi and Bluetooth


8.35


An 802.11 wireless LAN


8.36

• Hot spot: Geographic location in which an access point provides public Wi-Fi network service

• Bluetooth: Standard for wireless personal area networks that can transmit up to 722 Kbps within 10-meter area


Wireless Networks: Wi-Fi and Bluetooth


8.37

Is the World Falling for Wi-Fi?

Textbook Page 280

Case Analysis


8.38

• Frame relay• Asynchronous transfer mode (ATM)• Integrated Services Digital Network (ISDN)• Digital subscriber line (DSL)• T1 line• Network convergence• VAN: Value Added Network


Broadband Network Services and Technologies


8.39

• E-mail • Eliminates telephone tag and costly long-distance

telephone charges

• Groupware • Enables work groups at different locations to

participate in discussion forums and work on shared documents and projects

Electronic Business and Electronic Commerce Technologies

Electronic Mail and Groupware


8.40

• Voice mail• Digitizes spoken message and transmits it over a

network

• Fax• Digitizes and transmits documents over telephone

lines


Voice Mail and Fax


8.41

• Teleconferencing• Ability to confer with a group of people

simultaneously

• Data conferencing• Two or more users can edit and modify data files

simultaneously

• Videoconferencing• Participants are able to see each other over video

screens


Teleconferencing, Dataconferencing, and Videoconferencing


8.42

• Digital Information Services:• Online services providing general and business

information, such as LexisNexis, AOL, Dow Jones News

• Distance learning• Education or training delivered over a distance to

individuals in one or more locations• E-learning

• Instruction delivered online using the Internet or private networks


Digital Information Services, Distance Learning, and E-Learning


8.43

• Computer-to-computer exchange between two organizations of standard transaction documents, such as invoices, purchase orders

• Minimizes paper-handling and data input; lowers transaction costs

• Transmits structured data with fields, unlike e-mail


Electronic Data Interchange


8.44


Electronic data interchange (EDI)

Figure 8-10


8.45

1. Distance

2. Services

3. Points of access

4. Utilization

5. Cost

6. Security

7. Connectivity

Developing a Business-Driven Telecommunications Plan

Implementation Issues: Seven Factors

chapter 6 telecommunications, networks, and wireless computing 8.1 telecommunications, networks, and...

Documents

wireless computing session

information packets

packet communications

contemporary systems

types of information

transmission packets

group of computers

type of network network