1. Chapter 1 Panko and Panko Business Data Networks and Security, 9 th Edition © 2013 Pearson Panko and Panko Business Data Networks and Security, 9 th Edition © 2013 Pearson Revised August 2013

2.  Today, we are surrounded by networks.  This book will help you learn the skills you will need to participate in this networking revolution.  This chapter introduces basic network concepts and issues you will see throughout the book. 2 © 2013 Pearson

3. Difficult MaterialCentral Concept (CEPT) Take it slowly, step by step. This will require some extra work. This is a central concept (CEPT) you need to understand really well. 3 © 2013 Pearson

4. Into the Cloud Basic Network ConceptsPacket SwitchingInternetworkingLayersInternet StandardsA Small Home Network 4 © 2013 Pearson

5.  Works at the First Bank of Paradise (FBP) in Hawai`i  Develops new media marketing campaigns using Facebook, Twitter, YouTube, e-mail lists, and the bank’s website 5 © 2013 Pearson

6.  Current project is the AlohaSmart credit card smartcard ◦ Smartcards have chips as well as mag stripes 6 © 2013 Pearson

7.  At breakfast, Jason opens his tablet to check e-mail. Reads remarks sent by others about his PowerPoint marketing plan  Turns on his desktop computer and reworks the PowerPoint presentation  File is automatically uploaded “to the cloud” with BlueSynch  Later available to his work notebook and to meeting participants 7 © 2013 Pearson

8. The cloud imagery indicates that the user does not have to understand how systems “inside the cloud” operate. 8 © 2013 Pearson

9.  PowerPoint is software installed on his desktop computer at home.  For his work notebook computer and on his tablet, PowerPoint is software stored in the cloud. ◦ It downloads when he needs it. ◦ Pays for it by the month, as a service. ◦ It is called software as a service (SaaS). ◦ Also referred to as a hosted application 9 © 2013 Pearson

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11.  On the FBP networking staff  Manages the headquarters building wireless LANs  Walks around doing readings with her sniffer program  Learns information about access points, their signal strengths, and their security 11 © 2013 Pearson

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13. SSIDFBP BSSID A1-B2-C3- D4-E5-F6 BB-D5-33-D4- 6B-DD 19-FF-AE-D4- EC-63 Signal-85 dBm-60 dBm Mode802.11g802.11n Channel114844 EncryptionAES-CCMP AuthenticationWPA2/PEAP VendorCisco 13 © 2013 Pearson

14.  Currently, must walk around at least daily. ◦ Even then, cannot find intermittent problems.  FBP is installing a centralized wireless management system. ◦ Will be able to manage all access points centrally. ◦ She can constantly monitor the network for problems. ◦ The network will alert her to problems. ◦ The system can even make adjustments automatically. 14 © 2013 Pearson

15.  In charge of wireless security at FBP  BYOD (Bring Your Own Device) Problem ◦ Number of smartphones and tablets is exploding ◦ Owned by the employees but used partially for business purposes ◦ Great diversity in smartphone and tablet operating systems ◦ Device security is improving but limited 15 © 2013 Pearsonl

16.  Claire Lorek found a rogue access point in one of her walkarounds.  She and John visited Albert Gomes who installed the unauthorized access point.  Albert thought that the access point was secure in stealth mode.  However, Claire’s and hackers’ software could find it easily. 16 © 2013 Pearson

17.  Rather than punish Albert, they worked to help him.  His department did need more capacity.  Claire promised to install another access point, one with strong security.  John and Claire had developed an ally. 17 © 2013 Pearson

18. Into the Cloud Basic Network Concepts Packet SwitchingInternetworkingLayersInternet StandardsA Small Home Network 18 © 2013 Pearson

19. Working Definition 19 © 2013 Pearson

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21.  Which of the following is a host when it connects to a network? © 2013 Pearson 21

22.  The Internet of Things ◦ A term that means the trend of connecting almost all devices to the Internet ◦ There are many more things than people © 2013 Pearson 22

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24. 24 Each host has a unique address. Host 1 address = A47 Host 2’s address = Z12 Like telephone numbers Each host has a unique address. Host 1 address = A47 Host 2’s address = Z12 Like telephone numbers © 2013 Pearson

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26. The client and the server share processing work. 26 © 2013 Pearson

27.  Browser on the client machine is the client program ◦ Sends an HTTP request message asking for a file  Webserver program on the webserver host is the server program ◦ HTTP Response message contains the file to be delivered ◦ Or, the response may contain an error message if the file could not be delivered © 2013 Pearson 27

28. P2P Processing can be done without a network (as shown) or with a network. No servers are needed. 28 © 2013 Pearson

29. Transmission Speed Measurements Bits per second (bps) Usually not bytes per second (Bps) Metric Suffixes Kilobits per second kbps (lowercase k)1,000 bits per second (not 1,024) Megabits per second Mbps1,000 kbps Gigabits per second Gbps1,000 Mbps Terabits per second Tbps1,000 Gbps 29 © 2013 Pearson

30.  32,000 bps ◦ 32 kbps  67,670,000 bps ◦ 67.67 Mbps  197,270,000,000 bps ◦ 197.27 Mbps  57,000 kbps ◦ 57 Mbps © 2013 Pearson 30

31. File Downloads 100 kbps 1 Mbps 10 Mbps 100 Mbps 1 Gbps E-mail message (250 words).15 s0 s Photograph (5 MB)8 m1 m5 s1 s0.1 s 1 Hour HTDV Video (10 Mbps) 4 d10 h1 h6 m36 s Backup a Hard Disk (10 GB) 12 d28 h3 h17 m2 m 31 © 2013 Pearson

32. Into the CloudBasic Network Concepts Packet Switching InternetworkingLayersInternet StandardsA Small Home Network 32 © 2013 Pearson

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41.  Each switch along the way forwards the packet out a port to another switch (or to the destination host).  Individual packet switches have no knowledge of the entire path taken by the packet.  We will see how this works in detail in later chapters. 41 © 2013 Pearson

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44.  Forerunner of the Internet  Funded by Larry Roberts at the Advanced Research Projects Agency (ARPA) ◦ Now the Defense Advanced Research Projects Agency (DARPA)  To explore packet switching  To give researchers access to ARPA-funded software on host computers in distant cities  First four nodes began operation in 1969 44 © 2013 Pearson

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47. Into the CloudBasic Network ConceptsPacket Switching Internetworking LayersInternet StandardsA Small Home Network 47 © 2013 Pearson

48.  Bob Kahn at DARPA needed a way for researchers on one network to use resources on another network.  Packets would have to travel across multiple networks.  Kahn and Vint Cerf came up with the idea of connecting multiple networks by devices called routers. ◦ The original name was gateways.  Generically, networks of networks are internets.  Kahn created the global Internet (Capital I). 48 © 2013 Pearson

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50.  Capitalization of “internet” ◦ With an uppercase “I,” Internet means the global Internet we use every day. ◦ With a lowercase “i”, internet means any internet or the internet layer. 50 © 2013 Pearson

51.  Basically, Kahn and Cerf created a second layer of networking on top of single networks.  This required the creation of a parallel set of concepts for single networks and internets.  Single networks and internets use similar concepts but give these concepts different names.  It is important for you to get this clear in your head. 51 © 2013 Pearson

52. Component Generic Terminology Single Networks Internets Addresses Vary by network technology 32-bit IPv4 Addresses and 128-bit IPv6 Addresses Packets are calledPacketsFramesPackets Packet switches are called Switches Routers End-to-end routes are called Data linksRoutes 52 © 2013 Pearson

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56. Into the CloudBasic Network ConceptsPacket SwitchingInternetworking Layers Internet StandardsA Small Home Network 56 © 2013 Pearson

57.  Networks can be described at several layers of detail.  Each layer provides services to the layer above it. ◦ The road provides service to the car tires. ◦ The car tires provide service to the car. ◦ The car provides service to the driver. ◦ A commercial driver provides service to the goods being delivered. 57 © 2013 Pearson

58. 1. Physical links are connections between adjacent pairs of devices 1. Physical links are connections between adjacent pairs of devices 2. The data link is the packet’s path through the network In this case: X-A-B-D-F-Y 2. The data link is the packet’s path through the network In this case: X-A-B-D-F-Y 58 © 2013 Pearson

59. How many data links does the packet pass through? How many physical links does the packet pass through? Name them. How many data links does the packet pass through? How many physical links does the packet pass through? Name them. 59 © 2013 Pearson

60.  Formed by graduate students to create standards for the ARPANET.  Called their standards Requests for Comment (RFCs). ◦ Did not feel that they had the authority to create standards, so they used the weaker term RFC.  The NWG evolved into today’s standards body for the Internet, the Internet Engineering Task Force (IETF).  Internet standards today are still called RFCs. 60 © 2013 Pearson

61.  Basically, Kahn and Cerf created a second layer of networking on top of single networks.  This required the creation of a parallel set of concepts for single networks and internets.  Single networks and internets use similar concepts but give these concepts different names.  It is important for you to get this clear in your head. 61 © 2013 Pearson

62. 62 Dashed line shows the path of a packet Dashed line shows the path of a packet © 2013 Pearson

63. 63 How many physical links are there between the two hosts? How many physical links are there between the two hosts? Physical links connect adjacent devices, as noted earlier. Physical links connect adjacent devices, as noted earlier. © 2013 Pearson

64. 64 A data link is the path of a frame through a single network, as noted earlier. There is one data link per network. How many data links are in the figure? There is one data link per network. How many data links are in the figure? © 2013 Pearson

65. 65 A route is a packet’s path through an internet. Added for internets. A route is a packet’s path through an internet. Added for internets. How many routes are there in the figure? © 2013 Pearson

66.  Host P transmits a packet to Host Q.  There are seven networks between the hosts.  1. How many packets will there be along the way?  2. How many frames will there be along the way?  3. How many routes will there be along the way?  4. How many data links will there be along the way? 66 © 2013 Pearson

67. 67 Internet Layer Data Link Layer Physical Layer Provision of Service

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70. LayerNameBroad PurposeSpecific Purpose 5Application 4Transport 3Internet 2Data LinkSingle- network transmission (switched or wireless) Connection across a single network, Frame formats and switch operation 1PhysicalPhysical connections between adjacent devices 70 © 2013 Pearson

71. LayerNameBroad PurposeSpecific Purpose 5Application 4Transport Internet Transmission Application message fragmentation, error correction, congestion reduction, etc. 3InternetTransmission of packet across an internet, Packet formats, router operation 2Data Link 1Physical 71 © 2013 Pearson

72. NumberNameBroad PurposeSpecific Purpose 5ApplicationCommunication between applications Same 4Transport 3Internet 2Data Link 1Physical 72 © 2013 Pearson

73. 73 Application Layer Transport Layer Internet Layer Data Link Layer Physical Layer Provision of Service

74. Into the CloudBasic Network ConceptsPacket SwitchingInternetworkingLayers Internet Standards A Small Home Network 74 © 2013 Pearson

75.  IP ◦ Internet layer protocol ◦ Governs packet format ◦ Governs router operation ◦ Unreliable best-effort internet layer operation ◦ IPv4 is the current dominant version ◦ IPv6 is a new version that is growing rapidly 75 © 2013 Pearson

76.  Transmission Control Protocol (TCP) ◦ Transport layer protocol ◦ TCP messages are called segments ◦ Provides transport layer functionality to fix problems ◦ Error correction, and so on  User Datagram Protocol (UDP) ◦ The other transport layer protocol ◦ Messages are called datagrams ◦ Unreliable, so used when reliability is not desired 76 © 2013 Pearson

77. LayerStandard(s) Transport LayerTransmission Control Protocol (TCP) Fragmentation Error Correction Congestion control User Datagram Protocol (UDP) No Fragmentation No Error Correction No Congestion Control Internet LayerInternet Protocol (IP) IPv4 and IPv6 77 © 2013 Pearson

78.  1977 ◦ First experimental connection of three networks ◦ (Two wireless and the ARPANET)  1980s ◦ Internet opened to outside network for e-mail exchanges 78 © 2013 Pearson

79.  TCP/IP standards evolved in the 1980s ◦ Hosts could run either TCP/IP or NCP standards.  1983 ◦ All hosts were required to run TCP/IP.  NSFNET ◦ In the 1980s, the NSFNET funded by NSF was the core of the Internet. ◦ NSF had an Acceptable Use Policy barring commercial activity such as e-commerce. 79 © 2013 Pearson

80.  1995 ◦ NSFNET replaced by commercial ISPs. ◦ E-commerce was no longer forbidden. ◦ The e-commerce revolution began. ◦ The World Wide Web became popular just before that. 80 © 2013 Pearson

81. To use the Internet, you need an Internet service provider and an access line to your ISP. Your ISP gives you access and carries your packets. To use the Internet, you need an Internet service provider and an access line to your ISP. Your ISP gives you access and carries your packets. Organizations also need ISPs. Organizations also need ISPs. 81 © 2013 Pearson

82. ISPs collectively comprise the Internet backbone. They interconnect at Network Access Points (NAPs) to exchange packets. ISPs collectively comprise the Internet backbone. They interconnect at Network Access Points (NAPs) to exchange packets. 82 © 2013 Pearson

83. Trace the path packets take from the User PC to the Webserver. 83 © 2013 Pearson

84.  IP, TCP, and UDP are standards for delivering packets.  TCP/IP also has supervisory protocols: ◦ To handle things beyond packet delivery. ◦ Managing IP addresses. ◦ Error handling, and so on. ◦ We will look at two supervisory protocols in this chapter. ◦ We will look at many more in Chapter 10. 84 © 2013 Pearson

85. 85 © 2013 Pearson IP Addresses Network Address = F102A IP Address = 0.0.0.0 Network Address = F102A IP Address = 0.0.0.0

86. 86 © 2013 Pearson IP Addresses Network Address = F102A IP Address = 0.0.0.0 Network Address = F102A IP Address = 0.0.0.0

87. 87 © 2013 Pearson Network Address = F102A IP Address = Given IP Address Network Address = F102A IP Address = Given IP Address

88.  The Situation ◦ Your phone’s number is its network address ◦ People may only know your name ◦ Must look up your name in a telephone directory to find your phone number  Host Names ◦ Nicknames for certain hosts (usually servers) ◦ Users know these host names ◦ Need to be able to find a host’s IP address based on its host name © 2013 Pearson 88

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92. 92 © 2013 Pearson Once communication with the target host begins, the DNS servers has no further involvement

93.  DHCP gives the IP address of which host?  DNS gives the IP address of which host? © 2013 Pearson 93

94. Into the CloudBasic Network ConceptsPacket SwitchingInternetworkingLayersInternet Standards A Small Home Network 94 © 2013 Pearson

95. 95 © 2013 Pearson Physical Components

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98. The IP gives the home one IP address. The home network has multiple devices that need IP addresses. The IP gives the home one IP address. The home network has multiple devices that need IP addresses. 98 © 2013 Pearson

99. The access router DHCP circuit gives private IP addresses to other devices. The access router DHCP circuit gives private IP addresses to other devices. 99 © 2013 Pearson

100. NAT allows multiple internal hosts to share a single external IP address. External sniffers cannot learn internal addresses. NAT allows multiple internal hosts to share a single external IP address. External sniffers cannot learn internal addresses. 100 © 2013 Pearson

101. Into the CloudBasic Network ConceptsPacket SwitchingInternetworkingLayersInternet StandardsA Small Home Network 101 © 2013 Pearson

102.  This is the first of four introductory chapters. ◦ The others deal with standards, security, and network and security management.  Chapter 1 introduces basic network concepts and issues. ◦ Presented historically because some aspects of networking only make sense if you understand the development of internetworking. ◦ Specifically, single-network versus internet concepts and terminology (two of everything). 102 © 2013 Pearson

103.  Chapter 2 looks at standards in more depth. ◦ It will look at major characteristics of standards, such as the syntax of messages. ◦ It will focus on the data link, internet, transport, and application layers, which work by sending structured messages. 103 © 2013 Pearson