2. Jozef Goetz, 2009 1 1 Standards Clear visible standards. Students must have clear understandings learning standards in the areas of learning goals, lecture notes assignments and getting basic academics and applications skills. I would like to establish a clear system of standards learning standards are aligned with your expectations and the expectations of the global marketplace

3. Jozef Goetz, 2009 2 2 Standards Communication delivered over multiple channels is more efficient than communication over a single channel. Multiple channels make it more likely that the whole message will be received. An appropriate picture adds another channel by making a visual connection to an abstract idea. PowerPoint makes it easy to create visuals, and by using a template, makes it easy to be consistent.

4. Jozef Goetz, 2009 3 3 Research-based principles for design Power Point presentation Educational psychologist, Richard Mayer, posits a theory of multimedia learning wherein he finds seven research-based principles for design. Students learn better 1. from words and pictures than from words alone (Multimedia Principle) 2. when corresponding words and pictures are presented near rather than far from each other on the page or screen (Special Contiguity Principle) 3. when corresponding words and pictures are presented simultaneously rather than successively (Temporal Contiguity Principle) Mayer, R. (2001). Multimedia Learning. Cambridge University Press. Rodriguez, R. (2005) Theories Into Practice with Blackboard ONLINE, University of La Verne.

5. Jozef Goetz, 2009 4 4 Eyes are attracted to great contrast ●Contrast should fit information relevance ●Important information should have high contrast I use color or/and color ●Less relevant details should have lower contrast Context should be hierarchical ●Group related contexts ● More details should be indented Lecture Notes presentation

6. Jozef Goetz, 2009 5 5 Our eyes are attracted to: ●Size ●Contrast ●Texture ●Depth ●Motion To control focus, we use: ●Larger size ●Greater contrast ●Different color ●Hierarchy ●Should be easy to ignore lower levels as familiarity increases ●Sometimes animation Lecture Notes presentation

7. Jozef Goetz, 2009 6 6 Lecture Notes presentation Addition to that we introduce 1. Hierarchy of bullets Nested bulleted and numbered lists Level 1 item 1 Level 2 item 1 Level 2 item 2 Level 1 item 2 1. Level 2 item 1 2. Level 2 item 2 Higher level more general info Lower level more specific info 2. Key words in red 3. Important words in bold 4. Ability to learn from slides Example: Distributed Computing Work distributed over networks N-Tier applications Split parts of applications over numerous computers 1. User interface 2. Business-logic processing 3. Database Different parts interact when application runs

8. Jozef Goetz, 2009 7 7 My Lecture Notes: Have tutorial values: Comply with research-based principles for design Power Point presentation Concepts are presented visually with many diagrams and pictures. They use visual aids (diagrams, pictures etc.) and pictures are presented near each other on the page or screen. The context is presented in the hierarchical way, details are indented Important key words are highlighted or written in different color

9. Jozef Goetz, 2009 8 Overview of Data Communications and Networking PART I Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. expanded by Jozef Goetz, 2009

10. Jozef Goetz, 2009 9 Overview

11. Jozef Goetz, 2009 10 Chapters Chapter 1 Introduction Chapter 2 Network Models

12. Jozef Goetz, 2009 11 Chapter 1

13. Jozef Goetz, 2009 12 1.1 Data Communication The term telecommunication means communication at a distance.The term telecommunication means communication at a distance. The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data.The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data. Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable.Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable.

14. Jozef Goetz, 2009 13 1.1 Data Communication Data communication is the transfer of data from one device to another via some form of transmission medium. A data communications system must transmit data to the correct destination in an accurate and timely manner. A. Components B. Data Representation C. Direction of Data Flow

15. Jozef Goetz, 2009 14 A. Five components of data communication are the message, sender, receiver, medium, and protocol.

16. Jozef Goetz, 2009 15 B. Data Representation text, numbers, images, audio, and video are different forms of information.

17. Jozef Goetz, 2009 16

18. Jozef Goetz, 2009 17

19. Jozef Goetz, 2009 18 Figure 1.2 Simplex e.g. the keyboard and the monitor C. Direction of Data Flow

20. Jozef Goetz, 2009 19 Figure 1.2 Half-duplex e.g. Walkie-talkies, CB radios

21. Jozef Goetz, 2009 20 Figure 1.2 Full-duplex e.g. 2 people are communicating by a tel. line

22. Jozef Goetz, 2009 21 A network is a set of communication devices connected by media links. A network is a set of devices (often referred to as nodes) connected by communication links.A network is a set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, router or any other device capable of sending and/or receiving data generated by other nodes on the network.A node can be a computer, printer, router or any other device capable of sending and/or receiving data generated by other nodes on the network. 1.2 Networks

23. Jozef Goetz, 2009 22 1.Distributed Processing Task is divided 2.Network Criteria should be met Important: 1.Performance Metrics – they are contradictory Transit time (from A to B) Response time Throughput -How much data is sent Delay -traffic congestion 2.Reliability Measured by the freq. of failure 3.Security Protecting data from unauthorized access and damage 3.Physical Structures 4.Categories of Networks 1.2 Networks

24. Jozef Goetz, 2009 23 Figure 1.3 Point-to-point connection Physical Structures ad 3. Physical Structures In a point-to-point connection, two and only two devices are connected by a dedicated link.

25. Jozef Goetz, 2009 24 Figure 1.3 Multipoint connection (timeshare connection – capacity) In a multipoint connection, three or more devices share a link.

26. Jozef Goetz, 2009 25 1.2 NETWORKS How do we categorize? Topology, geography Technology Topologies Wide area networks - WAN Metropolitan networks - MAN Local area networks - LAN Personal networks - PN Technologies Circuit switched Packet switched

27. Jozef Goetz, 2009 26 Figure 1.4 Categories of topology (a network is layout physically) A topology is the geometric representation of the relationship of all the links and linking devices 4. Categories of Networks

28. Jozef Goetz, 2009 27 Figure 1.5 Fully connected mesh topology (for five devices) Every device has a dedicated point to point link to every other device How many physical links do we need for n nodes (devices)? -’s: Expensive Huge amount of cabling

29. Jozef Goetz, 2009 28 Figure 1.6 Star topology Each device has a dedicated point to point link only to a central controller, called a hub If one device wants to send data to another. It sends the data to the controller, which then relays the data to the other connected device. So, it doesn’t allow direct traffic between devices -’s: If one link fails, only that link is effected.

30. Jozef Goetz, 2009 29 Figure 1.7 Bus topology is multipoint, previous all were point to point connection One long cable acts as a backbone +s: include ease of installation nodes are connected to the bus cable by drop lines and taps cable redundancy is eliminated

31. Jozef Goetz, 2009 30 Figure 1.8 Ring topology Each device has a dedicated point to point link only with 2 devices on either side of it. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along.

32. Jozef Goetz, 2009 31 Figure 1.9 A hybrid topology: a star backbone with three bus networks

33. Jozef Goetz, 2009 32 Figure 1.10 An isolated LAN connecting 12 computers to a hub in a closet

34. Jozef Goetz, 2009 33 Categories of networks A network falls is determined by criteria: 1.Its size 2.Its ownership 3.The distance

35. Jozef Goetz, 2009 34 Networks LAN -- Local Area Network Usually confined to a single building or group of buildings MAN -- Metropolitan Area Network Connects computer resources in a local geographical area e.g. city WAN -- Wide Area Network Usually uses some form of public or commercial communications network to connect computers is widely dispersed geographical areas e.g. regions, countries, states, with a minimum distance typical of that between major metropolitan areas.

36. Jozef Goetz, 2009 35 LAN - Local Area Network Designed for a single office, campus, building or between nearby buildings. LANs allow resources to be shared Hardware Software Data between PCs or workstations. License restriction LANs are distinguished by three characteristics: – size restricted in size based on the size of the campus or building. – transmission technology broadcast networks – topology

37. Jozef Goetz, 2009 36 LANs - Transmission LANs are usually broadcast networks that are connected by a cable that attaches all of the computers together. LANs can run at speeds from 10Mbps to 10Gbps depending on the technology. LAN delays are usually small (microseconds) and few errors (scrambled data) occur.

38. Jozef Goetz, 2009 37 LAN (Continued) A given LAN use only one type of transmission medium. Speed : 4-16 Mbps Today: 10 Gbps

39. Jozef Goetz, 2009 38 MAN - Metropolitan Area Network (e.g. cable TV) Designed to extend over an entire city, connects LANs LANs can be shared - offices can be connected via a city Best known example – a cable TV network. Originally intended for TV only, it quickly became used for computer networks once the cable companies determined that there was money to be made.

40. Jozef Goetz, 2009 39 WAN - Wide Area Network Provides all transmission (data, video, image etc.) over large areas e.g. states, countries, a continent, or the whole world. In contrast to LANs may utilize public, leased, or private communication equipment. The user computers in a WAN are called hosts (owned by the customers). Host computers on various LANs are connected via a communication subnet (owned by a tel company or Internet service provider).

41. Jozef Goetz, 2009 40 Wide Area Networks Relation between hosts on LANs and the subnet. The subnet consists of routers and transmission lines. A router is a specialized piece of switching hardware that is responsible for determining the direction that data packets should be sent. Routers are responsible for directing data down transmission lines from one LAN to another.

42. Jozef Goetz, 2009 41 Figure 1.11 WANs: a. a switched WAN - use routers to coonect LANs and WANs b. a point-to-point WAN WAN can be as complex as the backbones that connect the Internet or a home computers to the Internet leased line dial up connection

43. Jozef Goetz, 2009 42 Wide Area Networks A stream of packets from sender to receiver. A subnet is organized according to the principle called store- and-forward or packet-switched subnet – The message sent by a process is broken down into smaller packets to send. – Each packet is sent out onto the network. – As a packet arrives at a router, it is stored (store-and-forward) there until the outgoing line is free. It is then sent on it’s way. – All the packets make take the same or different routes depending on if they are individually routed or not.

44. Jozef Goetz, 2009 43 A WAN connecting two LANs

45. Jozef Goetz, 2009 44 Figure 1.12 e.g. A heterogeneous network made of four WANs and two LANs

46. Jozef Goetz, 2009 45 Subnets (cont’d) It is possible to have a broadcast subnet. The best example is a satellite system, where the data is broadcast to everyone. With a satellite, no routing occurs at the satellite – it simply acts as a big dish to bounce signals off of.

47. Jozef Goetz, 2009 46 Wireless Networks. Wireless networks can be divided into three main categories: A.– System Interconnection B.– Wireless LANs C.– Wireless WANs Lets take a look at these three categories…

48. Jozef Goetz, 2009 47 A. System Interconnection We can use wireless technology to interconnect our system. – wireless mouse – wireless keyboard – wireless PDA Bluetooth is a wireless technology that would allow all sorts of digital devices (cameras, headsets, scanners, computers ) to “talk” to each other just by being close.

49. Jozef Goetz, 2009 48 Wireless Networks (a) Bluetooth configuration (master-slave paradigm, master determines how long, when and frequency slaves can use) (b) Wireless LAN Computers and printers can connect to the network with a radio communication link. There is usually a (or some) central access point or base station where the radio connections are converted to wire connections.

50. Jozef Goetz, 2009 49 B. Wireless LANs Computers may also be able to talk directly to one another if close enough together. Wireless is great for old homes you don’t want to wire and laptops that you want to be able to move around with. The standard is IEEE 802.11. It works on the same frequency as 2.4 GHz portable phones and Bluetooth. There are some compatibility issues between 802.11 and Bluetooth that have to be worked out.

51. Jozef Goetz, 2009 50 C. Wireless WANs – IEEE 802.16 Cell phone networks are a good example of wireless WANs. We are on our third generation of wireless WANs – there was analog voice, digital voice, and now digital voice and data. Distances are much greater than LANs, but bandwidth is much lower.

52. Jozef Goetz, 2009 51 Wireless Networks (a) Individual mobile computers (b) A flying LAN

53. Jozef Goetz, 2009 52 Home Network Categories. Many devices are capable of being networked: Computers (desktop PC, PDA, shared peripherals) Entertainment (TV, DVD, VCR, camera, stereo, MP3) Telecomm (telephone, cell phone, intercom, fax) Appliances (microwave, fridge, clock, furnace, airco, lights) Telemetry (utility meter, burglar alarm, thermostat, babycam). Many of us have them already – multiple computers all connected. What about connections to phones, entertainment systems, appliances and other devices? How practical is a home network? Will people pay so that their toaster can talk to their fridge?

54. Jozef Goetz, 2009 53 Home Network Categories Requirements: 1. Easy to install, manage 2. Foolproof in operation 3. High performance to connect multimedia devices 4. Low cost 5. Expand the network gradually 6. Secure and reliable

55. Jozef Goetz, 2009 54 Internetworks Replace the subnet by a WAN we’ll get Internetworks. The subnet consists of routers and transmission lines. A WAN contains both routers and hosts

56. Jozef Goetz, 2009 55 Internetworks A collection of interconnected networks is called an internetwork or internet. Connections are usually made through gateways that can provide the translation between the two different technologies. An internetwork is formed when distinct networks are connected ex: a LAN and a WAN or two LANs are connected

57. Jozef Goetz, 2009 56 Q 1- 10 ? p.24 Q 1- 10 ? p.24 TEST YOUR UNDERSTANDING

58. Jozef Goetz, 2009 57 1.3 The Internet The Internet has revolutionized many aspects of our daily lives.The Internet has revolutionized many aspects of our daily lives. It has affected the way we do business as well as the way we spend our leisure time.It has affected the way we do business as well as the way we spend our leisure time. The Internet is a communication system that has brought a wealth of information to our fingertips and organized it for our use.The Internet is a communication system that has brought a wealth of information to our fingertips and organized it for our use.

59. Jozef Goetz, 2009 58 1.3 The Internet A Brief History The Internet Today When 2 or more networks are connected, they become an internetwork, or internet. An internet is a network of networks. An "internet" (lower case i) is any computers connected to each other (a network), and are not part of the Internet unless the use TCP/IP protocols. The Internet (upper case) is a collaboration of more than 100s thousands interconnected networks. INTERNET (Upper case I) The vast collection of interconnected networks that all use the TCP/IP protocols and that evolved from the ARPANET of the late 60’s and early 70’s.TCP/IP The Internet is a structured, organized collection of many separate networks. TCP/IP is the protocol suite for the Internet. An "intranet" is a private network inside a company or organization that uses the same kinds of software that you would find on the public Internet, but that is only for internal use. An intranet may be on the Internet or may simply be a network.

60. Jozef Goetz, 2009 59 What is the World Wide Web? From the Free Online Dictionary of Computing, we get this definition from its entry for WWW:Free Online Dictionary of ComputingWWW "An Internet client-server hypertext distributed information retrieval system. " The Web is not a network. The Web is not the Internet itself. The Web is not a proprietary system like AOL. Instead the Web is a system of clients (Web browsers) and servers that uses the Internet for its data exchange. Web is a system of clients (Web browsers) and servers that uses the Internet for its data exchange On the WWW everything (documents, menus, indices) is represented to the user as a hypertext object in HTML format. Hypertext links refer to other documents by their URLs. hypertextHTMLHypertextlinksURLs These can refer to local or remote resources accessible via FTP, Gopher, Telnet or news, as well as those available via the http protocol used to transfer hypertext documents.FTP GopherTelnetnewshttphypertext

61. Jozef Goetz, 2009 60 What is the World Wide Web? The client program (known as a browser), e.g. NCSA Mosaic, Netscape Navigator, runs on the user's computer andbrowserNCSA MosaicNetscapeNavigator provides two basic navigation operations: to follow a link orlink to send a query to a server. A variety of client and server software is freely available.

62. Jozef Goetz, 2009 61 A brief history of the Internet. ARPANET (50s and 60s, some universities) NSFNET (late 70s, all universities) TCP/IP (invention ’74) became the official protocol in 1983. When NSFNET and the ARPANET were connected, the growth became exponential Many regional networks (Canada, Europe, the Pacific) joined up In mid-80s people began viewing the collection of networks as the Internet The glue that holds the Internet together is the TCP/IP reference model and TCP/IP protocol stack ANS (Advanced Networks and Service) by MERIT, MCI, and IBM took over NSFNET in 1990 and form ANSNET ANSNET sold to American Online in 1995.

63. Jozef Goetz, 2009 62 The ARPANET Growth of the ARPANET (a) December 1969. (b) July 1970. (c) March 1971. (d) April 1972. (e) September 1972.

64. Jozef Goetz, 2009 63 Figure 1.13 Hierarchical organization of the Internet End users to be connected use the services of Internet Service Provider (ISP) NAP = Network Access Point to the Internet Backbone in major cities, is the complex switching stations. Speed: up to 600 Mbps

65. Jozef Goetz, 2009 64 Figure 1.13 Internet today NAP = Network Access Point to the Internet Backbone in major cities, is the complex switching stations. Speed: up to 600 Mbps End users to be connected use the services of Internet Service Provider (ISP) There are local, regional, national, and international Internet service providers (ISPs).

66. Jozef Goetz, 2009 65 EO - End Office PSTN – Public Switching Telephony Network PBX – Private Exchange Switch

67. Jozef Goetz, 2009 66 1.4 Protocols and Standards Protocols Set of rules that governs data communication Key elements: Syntax Structure or format – order in which they are presented Semantics Meaning of each section of bits Timing What data and how fast they can be sent not to overload a receiver.

68. Jozef Goetz, 2009 67 A standard provides a model for development that enables a product to work regardless of the individual manufacturer Standards are essential in: i. Creating competitive markets for equipment manufacturers ii. Guaranteeing national and international interoperability and compatibility 1.4 Standards

69. Jozef Goetz, 2009 68 De Facto (by fact) standards Proprietary Nonproprietary De Jure (by law) standards read: dyzuri 1.4 Standards Categories

70. Jozef Goetz, 2009 69 Standards Organizations The ISO, ITU-T (previously CCITT), ANSI, IEEE, and EIA are some of the organizations involved in standards creation. 1.4 Protocols and Standards

71. Jozef Goetz, 2009 70 Forum Consist of representatives from interested corporations Present their conclusions to the standards bodies Facilitate standardization process Frame Relay Forum ATM Forum and Consortium Internet Society (ISOC) and Internet Engineering Task Force (IETF) 1.4 Protocols and Standards

72. Jozef Goetz, 2009 71 Forum are special-interest groups (work with universities and users), that evaluate and standardize new technologies. Internet Standards Is a thoroughly tested specification that is useful to and adhered to by those who work with the Internet First an Internet draft is published as a Request For Comment (RFC) is an idea or concept that is a precursor to an Internet standard. 1.4 Protocols and Standards

73. Jozef Goetz, 2009 72 ISO (International Standards Organization) 1946 – vast number of subjects 89 countries 13000 standards ISO is a member of ITU-T Documents are: Draft Draft International International Standard ANSI (American National Standards Institute) Private, nongovernmental, nonprofit organization NIST (National Institute of Standards and Technology) – a part of the US Dept of Commerce IEEE (Institute of Electrical and Electronics Engineering) Largest professional organization in the world ITU-T International Telecommunications Union - Telecommunications Standardization Sector (former CCITT) – 3000 recommendations 1.4 Protocols and Standards

74. Jozef Goetz, 2009 73 ISO ISO 8877—Interface in Integrated Services Digital Network (ISDN) ISO 3309—HDLC frame structure ISO 8028—X.25 packet level protocol 1.4 Protocols and Standards

75. Jozef Goetz, 2009 74 ITU-T V.32: Defines data transmission over phone lines X.25: Defines transmission over public digital networks I.430: Define physical layer specifications for an interface 1.4 Protocols and Standards

76. Jozef Goetz, 2009 75 ANSI X3. 23-1985 Programming language COBOL SONET Synchronous Optical Network ISDN Integrated Services Digital Network 1.4 Protocols and Standards

77. Jozef Goetz, 2009 76 IEEE IEEE 802.3: CSMA/CD LAN IEEE 802.4: Token Bus LAN IEEE 802.5: Token Ring LAN 1.4 Protocols and Standards

78. Jozef Goetz, 2009 77 EIA EIA-232: A 25-pin interface standard EIA-449: Specifies a 37-pin connector and a 9-pin connector EIA-530: Defines a 25-pin connector 1.4 Protocols and Standards

79. Jozef Goetz, 2009 78 Federal Communication Commission (FCC) Authority for interstate and international traffic Reviews communication services and prices Reviews technical specs of communication hardware Assigns carrier frequencies for radio and television Public Utility Commission (PUC) Authority for intrastate traffic 1.4 Regulatory Agencies 1.4 Regulatory Agencies

80. Jozef Goetz, 2009 79 IP Address Download and install free utility. Run it from Start => All Programs => VisualRoute 2009 – Lite Edition or from Internet Explorer under Tools

81. Jozef Goetz, 2009 80 IP Address Each device connected to the Internet has a unique numeric IP address. These addresses consist of a set of four groups of numbers, called octets. 66.94.234.13 will get you Yahoo! Use ping 66.94.234.13 ping yahoo.com tracert yahoo.com as exercises Your IP can be found here http://myip.dk/http://myip.dk/ exercises