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Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
8.1
Telecommunications, Networks, and Wireless Computing
SESSION 8
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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SENDER RECEIVERMEDIUM
Basic Communications Model
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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• Text
• Voice
• Image
• Video
Types of Data
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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
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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The Corporate Telecommunications System
A corporate telecommunications system
Figure 8-1
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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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
The Corporate Telecommunications System
Features of Contemporary Telecommunications Systems
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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
The Corporate Telecommunications System
Features of Contemporary Telecommunications Systems
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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The Corporate Telecommunications System
Packet-switched networks and packet communications
Figure 8-2
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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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
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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
The Corporate Telecommunications System
Features of Contemporary Telecommunications Systems
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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
The Corporate Telecommunications System
Features of Contemporary Telecommunications Systems
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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The Corporate Telecommunications System
The Transmission Control Protocol/Internet Protocol (TCP/IP) reference model
Figure 8-3
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Communication Media/Channels
Guided Media:Twisted PairCoaxial CableOptical Fiber
Unguided Media:MicrowaveSatelliteBroadcast Radio
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Twisted Pair
Coaxial Cable
Optical Fiber
Guided Media
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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• 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
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Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Microwave- “Line of sight” media:
antennas need to see each other
Unguided Media: Microwave
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Unguided Media: Satellite
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Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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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
The Corporate Telecommunications System
Transmission Media
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The Corporate Telecommunications System
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
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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
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Network Topology: STAR
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Network Topology: Bus
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Network Topology: Ring
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Communications Networks
Network topologies
Figure 8-8
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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
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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A Local Area Network (LAN)
COMMUNICATIONS NETWORKS
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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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
COMMUNICATIONS NETWORKS
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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• 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
Communications Networks
Wireless Networks: Wi-Fi and Bluetooth
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Communications Networks
An 802.11 wireless LAN
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• 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
Communications Networks
Wireless Networks: Wi-Fi and Bluetooth
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Is the World Falling for Wi-Fi?
Textbook Page 280
Case Analysis
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• Frame relay• Asynchronous transfer mode (ATM)• Integrated Services Digital Network (ISDN)• Digital subscriber line (DSL)• T1 line• Network convergence• VAN: Value Added Network
Communications Networks
Broadband Network Services and Technologies
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• 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
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• Voice mail• Digitizes spoken message and transmits it over a
network
• Fax• Digitizes and transmits documents over telephone
lines
Electronic Business and Electronic Commerce Technologies
Voice Mail and Fax
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• 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
Electronic Business and Electronic Commerce Technologies
Teleconferencing, Dataconferencing, and Videoconferencing
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• 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
Electronic Business and Electronic Commerce Technologies
Digital Information Services, Distance Learning, and E-Learning
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• 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 Business and Electronic Commerce Technologies
Electronic Data Interchange
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Electronic Business and Electronic Commerce Technologies
Electronic data interchange (EDI)
Figure 8-10
Chapter 6 Telecommunications, Networks, and Wireless ComputingChapter 6 Telecommunications, Networks, and Wireless Computing
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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