1. Networks and Telecommunications
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2. Opening Case: FedEx
Tracks each package through each step from shipper to recipient
Expanded into being a fully integrated corporate partner that picks up, transports, warehouses, and delivers a customer’s finished goods
E-business tools
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3. Applying Telecommunications in Business
TELECOMMUNICATIONS – the transmission of data between devices in different locations
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4. Vital Role of Telecommunications in E-Business
Telecommunications essential to:
E-retailers
E-marketplaces
Internet content providers
Internet service providers (ISPs)
Application service providers (ASPs)
Telephone and cable companies
Telecommunication equipment manufacturers
Internet and telecommunications software firms
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5. Convergence of Computing and Communications
Reliance of telecommunications on computers
Role of telecommunications in computing
New wired and wireless transmission
New combinations of data and computing
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6. Figure 10.1
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7. Figure 10.2
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8. Types of Networks
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9. A Typical Home Network Figure 10.3
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10. A Local Area Network (LAN) in a Business
LANs connect PCs and other equipment within a local area
Benefits:
Sharing equipment
Sharing personal files
Sending messages
Sharing databases
Administering software
Usually wired, but may also be wireless
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11. Figure 10.4
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12. A Telephone Network: Figure 10.6
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13. The Internet (From a User’s Viewpoint): Figure 10.7
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14. A Wide Area Network (WAN)
WANs are networks that span a wide geographical area
Many uses, e.g.,
Form the communication backbone for large distributed organizations
Focus on particular transaction processing application(s)
Transfer and consolidate corporate data, etc.
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15. Figure 10.8
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16. Functions and Components of Telecommunication Networks
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17. Basic Terminology
Network = a set of devices and communications channels
Devices are called nodes
Connectivity = the ability to transmit data between devices at different locations
Switching = the process of directing a signal from its source to its destination
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18. Channel = a path along which data are transmitted
Wired or wireless
Decoding = converting the data back into their original form upon arrival at its destination
Network management = the process of monitoring the network’s operations, detecting and repairing faults, and balancing traffic
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19. Figure 10.9
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20. Generating and Receiving Data
An ever increasing number of different types of devices can be connected to a network
General purpose
Special purpose
Front-end processor – a specialized computer that handles network traffic for another computer
Improves the efficiency of the overall system
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21. Transmitting Analog versus Digital Data
Data transmission requires that data be encoded as electrical or optical signals, and then decoded at destination
Two important factors:
Are the original data analog or digital?
Are the data transmitted in analog or digital form?
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22. Analog data, analog signal
Original signal added to a carrier signal
Used for voice communication
Analog data, digital signal
Data must be digitized
The digitized data are only an approximation of the original
The quality depends on the precision of the digitizing process
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23. Digital data, analog signal
Must use a modem at each end
Superimposes a pattern of 0s and 1s on the carrier signal
Digital data, digital signal
Modems are no longer needed
Digital subscriber line (DSL)
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24. Significance of analog vs. digital transmission
Digital technology improves the quality of the transmission
Digital coding allows for error detection and correction
Digital data can be readily manipulated
High definition television (HDTV)
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25. Directing Data From Source to Destination
Dedicated line – a telephone line leased by a firm, and used exclusively by that firm
Switch – a special purpose computer that directs incoming messages along a path
Private branch exchange (PBX) – a special-purpose computer that distributes calls within a customer’s site
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26. Circuit Switching vs. Packet Switching
The method used in telephone networks
Sets up a temporary circuit between the source and the destination
Resources are reserved for the duration of the session (call)
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27. PACKET SWITCHING:
Appropriate when data are transmitted infrequently from a large number of nodes
Used on the Internet
The message is divided into packets containing control information
No circuit is established
Provides better sharing of resources
Multiple users share the same resources
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28. Figure 10.13
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29. Transmitting Data Through Wire and Wireless Media
Bandwidth – corresponds to the capacity of the transmission channel
Mbps or Gbps
A major limitation for the information superhighway
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30. Wired Transmission TWISTED PAIR COAXIAL CABLE
Used for voice transmission and for low volume data transmission
Slow
COAXIAL CABLE
Used in LANs and for data transmissions of less than 10 miles
Faster and more versatile than twisted pair
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31. FIBER OPTIC Carries data in the form of light Extremely fast
Very light
Very difficult to tap into
Very little data loss
Costly
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32. Wireless Transmission Figure 10.16
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33. Telecommunications Standards
De facto standards – established by the fact that a product dominates the market, e.g., Windows
De jure standards – defined by industry groups or by the government
Many de facto standards become de jure standards
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34. The OSI (open systems interface) model is a framework for defining telecommunications standards
Covers all aspects of network operations and management
Developed by the International Standards Organization (ISO)
Each level in the model is implemented through protocols
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35. Figure 10.18
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36. TCP/IP (Transmission Control Protocol/ Internet Protocol)
Used on the Internet
Five layer model
HTML and HTTP are examples of application layer standards
Open vs. proprietary standards
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37. More About Network Technology
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38. More About LANs Main topologies:
Star – all messages go through a central node that serves as a switch
Ring – the nodes are linked directly in a closed loop
Bus – each node is attached to a central channel called a bus
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39. Token passing: Token – a bit pattern that circulates between the nodes
One of the most common methods for internal communication
Used in ring topologies
Token – a bit pattern that circulates between the nodes
To transmit data, a node appends it to the token
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40. LANs use two types of transmission:
Baseband – the entire capacity of the cable is used to transmit a single digitally encoded signal
Ex.: Ethernet
Broadband – the capacity of the cable is divided into separate frequencies to permit it to carry several signals at the same time
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41. Interconnection devices – a combination of hardware and software:
Routers
Bridges
Gateways
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42. More About WANs Virtual private networks (VPNs):
A private network configured within a public network
Can be built on top of the Internet
Service offered by the telephone companies and ISPs
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43. Value added networks (VANs):
Public data networks that “add value” by transmitting data and by providing access to commercial databases and software
Use packet switching
Subscription based
Often used in electronic data interchange (EDI) systems
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44. Public switched data network technologies (PSDN)
Data flows through a public network managed by a telecommunications carrier
Most common technologies:
ISDN (integrated service digital network)
X.25
Frame relay
Asynchronous transfer mode (ATM)
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45. Wireless Networking
Wireless application protocol (WAP) - a standard technology framework for wireless Internet
Allows for some of the Internet content to be accessed by mobile devices
Bluetooth – a fast short-range wireless technology
Wireless office
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46. IP Telephony Voice over the Internet
Limited by the packet switching technology currently used by the Internet
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47. Telecommunications Policy
Why should the government permit only some companies to sell products in a particular line of business?
What should be the rationale for regulating telecommunications and setting prices?
Who should be able to use specific public resources, such as radio frequencies?
To what extent is universal access possible and to what extent should it be guaranteed?
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