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Chapter 9 Communications and Networks

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Presentation on theme: "Chapter 9 Communications and Networks"— Presentation transcript:

1 Chapter 9 Communications and Networks

2 Communications -- Telecommunications
What are computer communications? Process in which two or more computers or devices transfer data, instructions, and information notebook computers Web-enabled PDAs smart phones servers GPS receivers desktop computers mainframe computers Tablet PCs p. 460 Fig. 9-1 Blackberry Video Next

3 Networks – Local Area Network
What is a local area network (LAN)? Network in limited geographical area such as home or office building Metropolitan area network (MAN) connects LANs in city or town p. 471 Fig. 9-10 Next

4 Communication Devices -- Hardware
Requirements Sending Device Initiates Instruction to Transmit Communications Device Connects Sending Device to Channel Connects Channel to Receiving Device Communications Channel or Transmission Media Media on Which Data Travels Receiving Device Accepts Transmission Communication Device = modem or wireless Channel = media and is the material that carries the signal: wired such as cable or wireless such as bluetooth p. 460

5 Communications Devices
What are examples of communications devices? Common types are dial-up modems, ISDN and DSL modems, cable modems, network cards, wireless access points, routers, and hubs ISDN and DSL modems send and receive data from ISDN and DSL lines p. 482 Next

6 Communications Channel also known as Transmission Media
What are examples of transmission media? Transfer Rates for Various Types of LANs Using Physical Transmission Media Wire, cable, and other tangible materials used to send communications signals e.g. DSL modem is the device; the copper wire in the modem is the channel or transmission medida p. 490 Fig. 9-35 Next

7 Wireless Transmission Media
What is wireless transmission media? Used when inconvenient, impractical, or impossible to install cables Includes Bluetooth and IrDA p. 494 Fig. 9-40

8 Networks Collection of Computers & Devices Connected via
Communications Devices -- Slide 5 Transmission Media – Slide 6 Communications device: modem Transmission media: telephone wire; cables; fiber optics

9 Uses of Computer Communications
What are some uses of communications technology? Internet Web Instant Messaging Chat Rooms Newsgroups Internet Telephony FTP Web Folders Video Conferencing Fax Machine or Computer Fax/Modem p. 462 Next

10 Uses of Computer Communications
What are Wireless Messaging Services? Text Messaging Send / Receive Short Text Messages Using Phone Picture Messaging Send / Receive Graphics, Pictures, Video, Sound

11 Uses of Computer Communications
What is a global positioning system (GPS)? Step 1. GPS satellites orbit Earth. Every 1/1000 of a second, each satellite sends a signal that indicates its current position to the GPS receiver. Step 2. A GPS receiver (such as in a car, a wearable device, a smart phone, a handheld device, or a collar) determines its location on Earth by analyzing at least 3 separate satellite signals from the 24 satellites in orbit. Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click GPS below Chapter 9 p. 466 Fig. 9-6 Next

12 Uses of Computer Communications
Groupware is software that allows people work together and share information MS Office 2007: SharePoint Server: A big share drive to share files with others at the college. What is groupware? A wave is equal parts conversation and document. People can communicate and work together with richly formatted text, photos, videos, maps, and more SharePoint video Google Wave p. 467 Fig. 9-7 Next

13 Network Types LAN (Local Area Network)
Network in Limited Geographical Area Typically Within a Building

14 Network Types What is a wide area network (WAN)?
Network that covers large geographic area using many types of media Internet is world’s largest WAN p. 472 Fig. 9-12 Next

15 Network Types What is a client/server network?
One or more computers act as server and other computers, or clients, access server Clients request RESOURCES on the server p. 472 Fig. 9-13 Next

16 Networks What is a site license?
Legal agreement that allows multiple users to run a software package simultaneously License fee usually based on number of users or number of computers attached to network

17 Networks What are the components of a client/server network?
File server Workstation Network interface card UPS Network Operating System Printers Backups p. 472 Fig. 9-12 Next

18 Network Types What is a peer-to-peer network?
Simple network that connects fewer than 10 computers Each computer, or peer, has equal capabilities p. 473 Fig. 9-14 Next

19 Network Types What is Internet peer-to-peer (P2P)?
Sometimes called a file sharing network Enables users to connect to each other’s hard disks and exchange files directly Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click BitTorrent below Chapter 9 p Fig. 9-15 Next

20 Criticism Illegal music/video sharing Strain on ISP Kazaa Napster
The Pirate Bay Strain on ISP Bandwidth supply < Bandwidth demand Revenge theory by economists Music industry has been taking advantage of consumers Sell 12-track albums for $15 only; no cheap singles Make one or two good songs; rest is second-rate Rationale -- Piracy is taking back money that industry “stole” Lesser-known artists distribute free music Artists believe that free distribution of music will result in greater attention More $$$ from concerts because of online popularity Some artists who are victim to piracy believe that from the exposure, they will profit more in live concert Why authors don’t have to worry Hard to read books on monitor (bad for eyes; long books) Books in-print more portable than e-books Non-fiction writers should worry more than fiction writers Fiction to be read in order, non-fiction to be read depending on section Textbook authors should worry

21 Network Topology Layout of devices in a network
Popular types of topology Bus Ring Star

22 Bus Topology What is a bus network?
All computers and devices connect to central cable, or bus

23 Star Topology What is a star network?
All devices connect to a central device, called hub All data transferred from one computer to another passes through hub p. 475 Fig. 9-17 Next

24 Networks What is a ring network?
Cable forms closed ring, or loop, with all computers and devices arranged along ring Data travels from device to device around entire ring, in one direction p. 474 Fig. 9-16 Next

25 Makes information accessible to employees
Networks What is an intranet? Internal network that uses Internet technologies Makes information accessible to employees Typically includes connection to Internet Don’t confuse and intranet with: Extranet allows customers or suppliers to access part of company’s intranet p. 475 Next

26 Networks What is an extranet?
Allows customers or suppliers outside of the company to access part of company’s intranet Customer checking package on Fed Ex’s intranet via the Internet

27 Bus Topology What is a bus network?
All computers and devices connect to central cable, or bus

28 Protocol & Standards -- Wired
Ethernet For LANs Uses Bus or Star Topology One of Most Widely Implemented Standards How Ethernet Cards Work TCP/IP stands for Transmission Control Protocol/Internet Protocol

29 Protocol & Standards -- Wired
TCP/IP-- Transmission Control Protocol/Internet Protocol Commonly Used for Internet Transmissions Packet Switching Transmits Data by Breaking it Into Packets Reassembles Data at Destination TCP/IP Animation TCP/IP stands for Transmission Control Protocol/Internet Protocol

30 Network Communications Standards
Wi-Fi identifies any network based on the standard that facilitates wireless communication Sometimes referred to as wireless Ethernet Compare speeds: 802.11p WAVE Wireless Access Vehicle Environments – transportation industry: speed of vehicles, airbag deployed? 802.11n vs g

31 How to Setup a Wireless Network

32 Network Communications Standards
Bluetooth limited to: 10 meters = 33 ft. TO 100 meters = 330 ft. Short-range Radio Technology IrDA Data Transferred via Infrared Light Waves Bluetooth exists in many products, such as telephones, the Wii and PS3. between two or more devices that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer sound data with telephones (i.e. with a Bluetooth headset) or byte data with hand-held computers (transferring files). p Fig. 9-20 Next

33 Protocols & Standards RFID -- Radio Frequency Identification – replace bar code reader Uses Radio Signals Communicates with Tag Placed in Object Legislation Nevada Require Retailers to Inform Customers Product is Tagged Rhode Island No Government Agency can Use to Track Individuals TX Prohibit Schools from Using RFID on Students Profile customer selections for marketing purposes, track movement thru store, possibly contents of purse thru cell phones; customer uses cell phone to find out more about the product How RFID Works RFID and Sushi

34 Network Communications Standards

35 Communications Over the Telephone Network
What is a dial-up line? Temporary connection using telephone line for communications Costs no more than making regular call Computers at any two locations can establish a connection using modems and telephone network

36 Communications Over the Telephone Network

37 The Telephone Network What is transfer rate?
Speed at which a line carries data and information Faster the transfer rate, the faster you can send and receive data and information Usually expressed as a measure of bits per second bits per second (bps) kilobits per second (Kbps) megabits per second (Mbps) gigabits per second (Gbps)

38 Communications Over the Telephone Network
What is a dedicated line? Always-on connection between two communications devices ISDN DSL T-carrier line ATM -- Asynchronous Transfer Mode Integrated Services Digital Network; FTTH – Fiber-to-the HOME; FTTB – Fiber to the Building; Both allow home and business high speed access to the Internet p. 482 Fig. 9-24 Next

39 Communications Devices --Wired
What are ISDN and DSL modems? Communications devices that send and receive digital ISDN and DSL signals Usually external devices in which one end connects to a telephone line and the other end connects to a port on the system unit p. 485 Next

40 Communications Devices
What is a cable modem? Sends and receives data over cable television network Much faster than dial-up modem or ISDN Sometimes called a broadband modem Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click Cable Modems below Chapter 9 p Fig. 9-28 Next

41 Cable Modem vs. DSL Cable Modem Advantage: Widespread Availability
Video –Cable & DSL Cable Modem Advantage: Widespread Availability Disadvantage: Competition with shared users DSL Not shared with other users Radius of user and service limited

42 Communications Over the Telephone Network
What is an ADSL (asymmetric digital subscriber line)? Popular type of DSL (Digital Subscriber Line) Faster when receiving data than when sending data Ideal for Internet access Test speed of modem: Next

43 Communications Devices
A network card enables a computer or device to access a network Available in a variety of styles Wireless network cards often have an antenna same waves used by cell phones

44 Communications Devices
A router connects multiple computers or other routers together and transmits data to its correct destination on a network Many are protected by a hardware firewall Fastest path available

45 Communications Devices
A hub or switch connects several devices in a network together

46 What's the difference between a hub and a router?
A hub just allows several network cables to be attached, putting several computers on the same network. A router has a processor that allows it to decide where to send traffic, and possibly to modify the details. A hub glues together an Ethernet network segment A router can do those functions plus route TCP/IP packets between multiple PCs on LAN and a WAN Some hubs include routers

47 Home Networks What is a home network?
Multiple computers connected in home Several types of wired home networks Ethernet — connect computers via cable Powerline cable — use electrical lines in house Phoneline — use telephone lines Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click Home Networks below Chapter 9 p Fig. 9-34 Next

48 Communications Channel
What is a communications channel? Transmission media on which data travels in communications system – both wired and wireless Transmission media are materials capable of carrying one or more signals Bandwidth is amount of data that can travel over a communications channel p. 491 Next

49 What is physical transmission media?
p. 492 Fig. 9-36

50 Physical Transmission Media
What are twisted-pair cable and coaxial cable? Twisted-pair cable is used for telephone systems and network cabling Coaxial cable is often used for cable television wiring p. 493 Fig. 9-37—9-38 Next

51 Physical Transmission Media
What is fiber-optic cable? Capable of carrying significantly more data at faster speeds than wire cables Less susceptible to interference (noise) and, therefore, more secure Smaller size (thinner and lighter) How fiber optic tubes are manufactured 4/9/09 Fiber Optic Cable Security? p. 493 Fig. 9-39 Next

52 Wireless Transmission Media
What is wireless transmission media? Used when inconvenient, impractical, or impossible to install cables Includes Bluetooth and IrDA p. 494 Fig. 9-40

53 Wireless Transmission Media
Microwave Station Earth-based Reflective Dish Contains Antenna, Transceivers Uses Line-of-sight Transmission –straight line with no obstructions Universities, hospitals, government, cable television

54 Wireless Transmission Media
Satellite Space Station Receives Microwave Signals Broadcasts Signals Back to Earth-based Stations TV, GPS, air navigation

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