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Communications & Networks


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  • 1. + Communications and Networks Internet Resources
  • 2. + Unit Objectives  After completing this chapter you will be able to:  Discuss the purpose of the components required for successful communications and identify various sending and receiving devices  Describe various uses of computer communications  List the advantages of using a network, and differentiate among LANs, MANs and WANs  Differentiate between client/server and peer-to-peer networks, and describe how P2P networks work
  • 3. + Unit Objectives  Differentiate among a star, bus, and ring network  Describe the various network communications standards  Explain the purpose of communications software  Describe commonly used communications devices  Discuss different ways to set-up a home network  Describe various physical and wireless transmission media
  • 4. + Communications Communications and Networks
  • 5. + Communications  Computer communications describes a process in which two or more computers or devices transfer data, instructions, and information  Today, even the smallest devices can communicate with each other – often via the Internet
  • 6. + Communications  For successful communications you need:  A sending device that initiates an instruction to transmit data, instructions or information  A communication channel or transmission media on which the data, instructions, or information travel  A communication device that connects the communications channel to a receiving device that accepts the transmission
  • 7. + Uses of Communications Communications and Networks
  • 8. + Uses of Communications  Computer communications are everywhere  Many require that you subscribe to an Internet access provider  With others, organizations such as a business or school provide the communications services
  • 9. + Summary of Communications Previously Discussed Communications Previously Discussed Blogs Newsgroups Chat Rooms RSS E-Mail Video Conferencing Fax VoIP FTP Web 2.0 Instant Messaging Wikis
  • 10. + Wireless Messaging Services  Users can send and receive wireless messages to and from smartphones, cell phones, and handheld game consoles using three techniques  Text messaging  Picture/Video messaging, and  Wireless Instant Messaging  The type of messaging depends on the on the services offered by your wireless Internet service provider, or WISP
  • 11. + Text Messaging  A mobile device with text messaging allows users to send and receive short text messages on a phone or other mobile device  Services allow the user options to send and receive:  Mobile to Mobile  Mobile to E-Mail  Web to Mobile, and  Mobile to Provider
  • 12. + Picture/video messaging  With picture messages users can pictures and sound files, as well as short text messages, to another device  With video messages users can send short, about :30, videos is addition to other type of messages  Smart phones and other devices using MMS, typically have a built-in camera  As a consumer, you should be aware of memory availability and camera quality
  • 13. + Wireless Instant Messaging  Wireless instant messaging (IM) is a real-time communications service that allows mobile devices to exchange messages with other online users  Some WISPs partner with IM services  AT&T allows communications through AIM, Windows Live Messenger, and Yahoo! Messenger
  • 14. + Wireless Access Points  People connect everyday to wireless access points using their mobile devices to access Internet-based services  Two Types:  Hot Spots, &  Mobile Wireless Networks
  • 15. + Hot Spots  Is a network that provides wireless Internet connections to mobile devices  Three technologies  Wi-Fi (local, within a building or room)  WiMax (regional, withing a community)  Bluetooth (location-based hot spots)  Some hot spots are free, schools & coffee shops, and some are subscription-based
  • 16. + Mobile Wireless Network  Provided by cell phone companies, for their devices to access their networks  Coverage and speed depends on the carrier  Most common speed is 3G  “4G” networks are becoming available
  • 17. + GPS  Short for Global Positioning System  Uses satellite triangulation to pinpoint a location usually within 10-100 meters  Examples  Smart phones  Car Navigation systems  Handheld systems for hiking  Access to additional features
  • 18. + Geocaching  Geocaching is a real-world outdoor treasure hunting game.  Players try to locate hidden containers, called geocaches, using GPS-enabled devices and then share their experiences online. 
  • 19. + Collaboration  People use the Internet to collaborate, or work together online  Methods of collaboration  E-mail  Collaborative Software  Document Management Systems
  • 20. + E-mail  Oldest form of collaboration  Users send information and documents back and forth through their e-mail accounts  Pros  Quick and inexpensive  Cons  Creates multiple versions of a document  Information can get lost in the mix
  • 21. + Collaborative Software  Tools that enable users to share documents via online meetings and communicate with other connected users  Sometimes called a Web Conference or Web Meeting  Examples  Microsoft Groove or Office Live Meeting  WebEx  Google Apps  GoToMeeting
  • 22. + Document Management Systems  Provides storage and management of a users documents  Users can be granted access to each others documents  Only one document exists, not multiple versions  Examples  Windows Live SkyDrive  Google Docs
  • 23. + Cybercafés  Also know as an Internet Café, is a location, usually a coffeehouse or restaurant, that provides Internet access to its customers  Examples  Starbucks  Burger King  McDonalds
  • 24. + Web Services  A Web service is a method of communication between two electronic devices over the web.  The service can be integrated into any web page so users can easily access it  They do not require a specific programming language, operating system or web browser  Examples  Google Apps, Google Cloud Print, Office 365
  • 25. + Networks LANs, MANs, and WANs Network Architectures Network Topologies Intranets
  • 26. + Networks  A network is a collection of computers and devices connected together via communications devices and transmission media  A network can be internal to an organization or span the entire world  Why network?  Facilitating communications  Sharing hardware  Sharing data and information  Sharing software  Transferring funds
  • 27. + LANs, MANs, & WANs  Networks can be classified is three categories 1. Local Area Network 2. Metropolitan Area Network 3. Wide Area Network
  • 28. +Local Area Network (LAN)A network that connects computers and devices in a limited geographicalarea, such as a home, computer lab, or office building
  • 29. + WLAN  A wireless LAN is a LAN that uses no physical wires  Computers and devices that access a WLAN must have built-in wireless capability, or an appropriate adapter  Very often WLANs are setup side-by-side with a traditional LAN
  • 30. + Metropolitan Area Network (MAN)  A high-speed network that connects local area networks in a metropolitan area such as a city or town  A MAN typically includes one or more LANs but covers a smaller geographic area then a WAN  Managed by a Network Provider such as a state government, telephone company, or cable provider
  • 31. + Wide Area Network (WAN)  Network that covers a large geographic area, such as a city, country or the world  A WAN can be one large network or consist of two or more LANs  The Internet is the worlds largest WAN
  • 32. + Network Architectures The design of computers, devices, and media in a network, sometimes called network architecture, is categorized as either client/server or peer-to-peer
  • 33. + Client/Server  On a client/server network, one or more computers act as a server, and the other computers request services from the server  A server, sometimes called a host computer, control access to the hardware, software, and other resources on the network  The clients are other computers or mobile devices on the network that rely on the server for its resources
  • 34. + Peer-to-Peer  Simple, inexpensive network that typically connects fewer than 10 computers or other devices  Each computer, or peer, has equal responsibilities and capabilities  Each computer stores files on its own hard drives for sharing  Ideal for very small businesses and home networks
  • 35. + Internet Peer-to-Peer  P2P describes an Internet network on which users access each other’s hard disks and exchange files  Sometimes called a file-sharing network  Examples:  BitTorrent  Gnutella  Kazaa  LimeWire  Responsible for the majority of illegal file-sharing on the Interent
  • 36. + Network Topologies Star Bus Ring Intranets
  • 37. + Network Topologies  A network topology refers to the layout of computers and devices in a communications network  Three most common topologies: 1. Star 2. Ring, and 3. Bus  Most networks, including the Internet, use a combination of the three
  • 38. + Star Network  All of the computers and Node Hub/Switch devices, called nodes, connect to a central device, usually called a hub or a switch  All data is transferred through the hub or switch  Fairly easy to install  Nodes can be added and removed without affecting the rest of the network
  • 39. + Bus Network Bus  Consists of a central cable to which all computers and other devices connect  The bus is the physical cable that connects everything  Popular because they are inexpensive and easy to install  Devices can be added, removed, and moved with ease  If the bus fails, the entire Node network goes down
  • 40. + Ring Network Node  A cable forms a closed loop, or ring, with every device  Data travels from device to device on the ring until it reaches its destination  If one device fails, the entire network could possibly go down
  • 41. + Intranets  An intranet is an internal network that uses Internet technologies  Intranets usually make company information accessible to employees  Examples:  Telephone directories  Event calendars  Job postings  Video conferencing  Accessed through a web browser where changes can be made by everyone
  • 42. + Network Communication Standards Ethernet UWB Token Ring IrDA TCP/IP RFID Wi-Fi WiMAX Bluetooth WAP
  • 43. + Network Communication Standards  Today’s networks connect a variety of devices across many different networks, such as wide area, local area and wireless.  All networks must use similar techniques for connecting devices to ensure compatibility  Two regulating organizations 1. ANSI 2. IEEE  These organizations propose, develop, and approve network standards
  • 44. + Network Communications Standards  A network standard defines guidelines that specify:  The way computers access the medium to which they are attached,  The type(s) of medium used,  The speeds used on different types of networks, and  The type(s) of physical cable and/or the wireless technology used  A that standard outlines characteristics of how two networks communicate is called a protocol
  • 45. + Widely Used Standards & Protocols  You are to choose a standard or protocol below to research on a and report to the class 1. Ethernet 2. Token Ring 3. TCP/IP 4. Wi-Fi 5. Bluetooth 6. UWB 7. IrDA 8. RFID 9. WiMAX 10. WAP