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Communications & Networks

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Presentation on theme: "Communications & Networks"— Presentation transcript:

1 Communications & Networks
Chapter 8 Communications & Networks

2 Overview Identify Various Communication Uses List Network Advantages
Differentiate Network Types Describe Communications Standards Describe Communications Devices Identify Different Transmission Media

3 Communications Two or More Devices Requirements
Transfer Data or Instructions Requirements Sending Device Communications Device Connects Sending Device to Channel Connects Channel to Receiving Device Communications Channel Media on Which Data Travels Receiving Device

4 Uses Wireless Messaging Text Messaging Picture Messaging
Send / Receive Text Messages Using Phone 14-17: 60 v. 5 Picture Messaging Send / Receive Graphics, Pictures, Video Sexting: 30% of 17-year-olds Loss of Reaction : Alcohol=12%, Marijuana=21%, Texting=35% Pew Internet 5/10 Pew Internet 12/09

5 Uses GPS (Global Positioning System) Groupware
Signals Sent by Satellites Orbiting Earth Signal Sent Every 1/1000 of a Second Earth-based Receivers Analyze Signals Determine Receiver’s Geographic Location Groupware Assists Groups in Working Together Share Data Over Network e.g., Schedule Meetings

6 Uses Web Services Software Applications Mashup
Communicate with Other Remote Computers Use Internet or Internal Business Network Mashup Combines Services from Multiple Sources

7 Uses Very Hard to Give Up Pew Internet 3/08

8 Networks Collection of Computers & Devices Connected via Advantages
Communications Devices Transmission Media Advantages Facilitating Communications Sharing Hardware Sharing Software Sharing Data And Information

9 Network Types LAN (Local Area Network) WLAN WAN (Wide Area Network)
Network in Limited Geographical Area Typically Within a Building WLAN Wireless LAN WAN (Wide Area Network) Large Geographic Area Uses Many Types of Media Internet

10 Network Architectures
Client/Server Client Requests Resource Accessed from Server Server One or More Computers Controlling Resource P2P (Peer-to-Peer) Access Any Other Computer in Network Internet File Sharing

11 Network Topology Configuration of Devices in a Network Bus
Consists of Single Central Cable All Devices Connect to it Inexpensive & Easy to Install

12 Network Topology Ring Star Cable Forms Closed Ring
Data Travels In One Direction Expensive & Difficult to Install Star All Devices Connect to Hub All Data Passes Through Hub Bottlenecks Can Occur Easy to Install

13 Intranet & Extranet Intranet Extranet Internal Corporate Network
Uses Internet Accessible to Corporate Employees Facilitates Working in Groups Extranet Allows Access to Parts of a Intranet Customers / Suppliers

14 Protocol Protocol Collection of Procedures Type of Error Checking Used
Establish, Maintain, & Terminate Transmissions Type of Error Checking Used Data Compression Method, If Any Indicate Finished Sending Message Indicate Message Has Been Received

15 Standards Ethernet TCP/IP For LANs Uses Bus or Star Topology
Widely Implemented TCP/IP Used for Internet Transmissions Packet Switching Transmits Data by Breaking it Into Packets Reassembles Data at Destination

16 Standards 802.11 (Wi-Fi) 802.16 (WiMAX) Bluetooth WAP
Family of Standards for Wireless LANs (WiMAX) Towers Cover 30-mile Radius Provides Wireless Broadband Internet Bluetooth Short-range Radio Technology WAP Wireless Mobile Devices Connect to Internet

17 Standards IrDA RFID Data Transferred via Infrared Light Waves
Radio Signals Communicate with Tags Failed Legislation Nevada Require Retailers to Inform Customers Rhode Island Government Agency Cannot Track Individuals Texas Prohibit Schools from Using RFID on Students

18 Types & Speeds Measured in bps (Bits per Second)

19 Devices Modem DSL Modem Cable Modem
Converts Analog to Digital & Vice Versa Required for Telephone Line Communication DSL Modem Cable Modem Uses Cable TV Network

20 Devices Wireless Modem Network Card Wireless Access Point
Internet Access Network Card Connects PC to Network Wireless Access Point

21 Devices Router Hub / Switch Connects Multiple Computers / Routers
Transmits Data to Network Destination Uses Fastest Available Path Many Protected by Hardware Firewall Hub / Switch Provides Central Point for Network Cables

22 Channel Communication Path Between Devices Bandwidth Latency
Difference Between Frequencies Amount of Data that Travel Over Channel Latency Time for Signal to Travel From One Network Location to Another

23 Channel Broadband Transmission Media
Transmit Multiple Signals over Channel Transmission Media Materials or Techniques Capable of Carrying Signals

24 Physical Transmission Media
Twisted-pair Telephone System Coaxial Cable Cable Television Fiber-optic Thin Strands of Glass or Plastic Uses Light to Transmit Signals Less Susceptible to Interference More Secure

25 Wireless Transmission Media
Broadcast Radio Distributes Radio Signals Long & Short Distances Cellular Radio Widely Used for Mobile Communications

26 Wireless Transmission Media
Microwave Station Earth-based Reflective Dish Contains Antenna, Transceivers Uses Line-of-sight Transmission Satellite Space Station Receives Microwave Signals Amplifies Signals Broadcasts Signals Back

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