Welcome to the Cloud Chapter 1 Panko and

Welcome to the Cloud Chapter 1 Panko and Panko Business Data Networks and Security, 9 th Edition © 2013 Pearson Revised August 20

This Chapter 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. © 2013 Pearson 2

Special Notices Difficult Material Central 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. © 2013 Pearson 3

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 4

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

1. 1: Aloha. Smart Credit Card Current project is the Aloha. Smart credit card smartcard ◦ Smartcards have chips as well as mag stripes © 2013 Pearson 6

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

1. 2: Cloud File Synch/Distribution The cloud imagery indicates that the user does not have to understand how systems “inside the cloud” operate. © 2013 Pearson 8

Jason Akana Power. Point is software installed on his desktop computer at home. For his work notebook computer and on his tablet, Power. Point 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 (Saa. S). ◦ Also referred to as a hosted application © 2013 Pearson 9

1. 3: Software in the Cloud © 2013 Pearson 10

Claire Lorek 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 © 2013 Pearson 11

1. 4: Wireless Sniffer Radar Map © 2013 Pearson 12

1. 5: Wireless Sniffer Details Table SSID FBP FBP -85 d. Bm -60 d. Bm Mode 802. 11 g 802. 11 n Channel 11 48 44 Encryption AES-CCMP Authentication WPA 2/PEAP Vendor Cisco BSSID Signal © 2013 Pearson A 1 -B 2 -C 3 -D 4 BB-D 5 -33 -D 4 - 19 -FF-AE-D 4 -E 5 -F 6 6 B-DD EC-63 13

Claire Lorek � 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. © 2013 Pearson 14

John Lee 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 © 2013 Pearsonl 15

John Lee 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. © 2013 Pearson 16

John and Claire 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. © 2013 Pearson 17

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 18

1. 6: Basic Network Terminology Working Definition © 2013 Pearson 19

1. 6: Basic Network Terminology © 2013 Pearson 20

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

Hosts 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

1. 6: Basic Network Terminology © 2013 Pearson 23

1. 6: Basic Network Terminology Each host has a unique address. Host 1 address = A 47 Host 2’s address = Z 12 Like telephone numbers © 2013 Pearson 24

1. 6: Basic Network Terminology © 2013 Pearson 25

1. 7: Client/Server Processing The client and the server share processing work. © 2013 Pearson 26

Client/Server Processing: The Web 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

1. 8: Peer-to-Peer (P 2 P) Processing P 2 P Processing can be done without a network (as shown) or with a network. No servers are needed. © 2013 Pearson 28

1. 9: 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 Mbps 1, 000 kbps Gigabits per second Gbps 1, 000 Mbps Terabits per second Tbps 1, 000 Gbps © 2013 Pearson 29

1. 9 Transmission Speed 32, 000 bps ◦ 32 kbps 67, 670, 000 bps ◦ 67. 67 Mbps 197, 270, 000 bps ◦ 197. 27 Mbps 57, 000 kbps ◦ 57 Mbps © 2013 Pearson 30

1. 10: Download Times for Applications File Downloads 100 kbps 1 Mbps 100 Mbps 1 Gbps E-mail message (250 words) . 15 s 0 s 0 s Photograph (5 MB) 8 m 1 m 5 s 1 s 0. 1 s 1 Hour HTDV Video (10 Mbps) 4 d 10 h 1 h 6 m 36 s Backup a Hard Disk (10 GB) 12 d 28 h 3 h 17 m 2 m © 2013 Pearson 31

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 32

1. 11: Data Burstiness © 2013 Pearson 33

1. 11: Data Burstiness © 2013 Pearson 34

1. 12: Packet Switching and Multiplexing © 2013 Pearson 35

1. 12: Packet Switching and Multiplexing © 2013 Pearson 36

1. 13: Sequential Switching Decisions © 2013 Pearson 37

1. 13: Sequential Switching Decisions © 2013 Pearson 38

1. 13: Sequential Switching Decisions © 2013 Pearson 39

1. 14: Address-Based Switch Forwarding Decision © 2013 Pearson 40

Recap 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. © 2013 Pearson 41

1. 15: Physical and Data Links © 2013 Pearson 42

1. 15: Physical and Data Links © 2013 Pearson 43

The ARPANET � 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 © 2013 Pearson four nodes began operation in 1969 44

1. 16: The ARPANET © 2013 Pearson 45

1. 16: The ARPANET © 2013 Pearson 46

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 47

Birth of the Internet � 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, � Kahn © 2013 Pearson networks of networks are internets. created the global Internet (Capital I). 48

1. 17: Internet © 2013 Pearson 49

Terminology 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. © 2013 Pearson 50

1. 18: Two Layers of Networking � 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. © 2013 Pearson 51

1. 18: Two Layers of Networking Component Generic Terminology Addresses Packets are called Packet switches are called End-to-end routes are called © 2013 Pearson Packets Switches Single Networks Internets Vary by network technology 32 -bit IPv 4 Addresses and 128 -bit IPv 6 Addresses Frames Packets Data links Routes Switches Routers 52

1. 19: Packets and Frames © 2013 Pearson 53

1. 19: Packets and Frames © 2013 Pearson 54

1. 19: Packets and Frames © 2013 Pearson 55

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 56

Network layers 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. © 2013 Pearson 57

1. 20: Physical Links and Data Links 2. The data link is the packet’s path through the network In this case: X-A-B-D-F-Y 1. Physical links are connections between adjacent pairs of devices © 2013 Pearson 58

1. 20: Physical Links and Data Links How many data links does the packet pass through? How many physical links does the packet pass through? Name them. © 2013 Pearson 59

Network Working Group � 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 © 2013 Pearson standards today are still called RFCs. 60

Two Layers of Networking � 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. © 2013 Pearson 61

1. 20: Physical Links, Data Links, and Routes Dashed line shows the path of a packet © 2013 Pearson 62

1. 20: Physical Links, Data Links, and Routes Physical links connect adjacent devices, as noted earlier. How many physical links are there between the two hosts? © 2013 Pearson 63

1. 20: Physical Links, Data Links, and Routes 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? © 2013 Pearson 64

1. 20: Physical Links, Data Links, and Routes A route is a packet’s path through an internet. Added for internets. How many routes are there in the figure? © 2013 Pearson 65

1. 20: Physical Links, Data Links, and Routes � 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? © 2013 Pearson 66

Layers Provision of Service Internet Layer Data Link Layer Physical Layer © 2013 Pearson 67

1. 21: Internet and Transport Standards © 2013 Pearson 68

1. 21: Internet and Transport Standards © 2013 Pearson 69

1. 22: Networking Layers Layer 5 4 3 Name Broad Purpose Specific Purpose Application Transport Internet 1 Physical 2 © 2013 Pearson Data Link Singlenetwork transmission (switched or wireless) Connection across a single network, Frame formats and switch operation Physical connections between adjacent devices 70

1. 22: Networking Layers Layer Name Broad Purpose 5 Application 4 Transport 3 Internet 2 1 Data Link Physical © 2013 Pearson Internet Transmission Specific Purpose Application message fragmentation, error correction, congestion reduction, etc. Transmission of packet across an internet, Packet formats, router operation 71

1. 22: Networking Layers Number Name Broad Purpose Specific Purpose 5 Application Communication Same between applications 4 Transport 3 Internet 2 Data Link 1 Physical © 2013 Pearson 72

Layers Application Layer Provision of Service Transport Layer Internet Layer Data Link Layer Physical Layer © 2013 Pearson 73

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 74

1. 24: Core TCP/IP Standards IP ◦ Internet layer protocol ◦ Governs packet format ◦ Governs router operation ◦ Unreliable best-effort internet layer operation ◦ IPv 4 is the current dominant version ◦ IPv 6 is a new version that is growing rapidly © 2013 Pearson 75

1. 24: Core TCP/IP Standards � 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 © 2013 Pearson 76

1. 23: Core TCP/IP Standards Layer Transport Layer Internet Layer © 2013 Pearson Standard(s) Transmission User Datagram Control Protocol (UDP) (TCP) No Fragmentation No Error Correction No Congestion control Control Internet Protocol (IP) IPv 4 and IPv 6 77

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

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

The Internet Evolves 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. © 2013 Pearson 80

1. 24: The Internet Today 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. © 2013 Pearson 81

1. 24: The Commercial Internet ISPs collectively comprise the Internet backbone. They interconnect at Network Access Points (NAPs) to exchange packets. © 2013 Pearson 82

1. 24: The Commercial Internet Trace the path packets take from the User PC to the Webserver. © 2013 Pearson 83

Internet Supervisory Protocols � 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. © 2013 Pearson 84

1. 25: Dynamic Host Configuration Protocol Network Address = F 102 A IP Address = 0. 0 © 2013 Pearson IP Addresses 85

1. 25: Dynamic Host Configuration Protocol Network Address = F 102 A IP Address = 0. 0 © 2013 Pearson IP Addresses 86

1. 25: Dynamic Host Configuration Protocol Network Address = F 102 A IP Address = Given IP Address © 2013 Pearson 87

1. 26: Domain Name System (DNS) 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

1. 26: Domain Name System (DNS) © 2013 Pearson 89

1. 26: Domain Name System (DNS) © 2013 Pearson 90

1. 26: Domain Name System (DNS) © 2013 Pearson 91

1. 26: Domain Name System (DNS) Once communication with the target host begins, the DNS servers has no further involvement © 2013 Pearson 92

Both DHCP and DNS give the requesting host an IP address DHCP gives the IP address of which host? DNS gives the IP address of which host? © 2013 Pearson 93

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 94

1. 27: Home Network Physical Components © 2013 Pearson 95

1. 28: Four-Pair Unshielded Twisted Pair (UTP) © 2013 Pearson 96

1. 27: Home Network Services © 2013 Pearson 97

1. 29: DHCP in a Small Home Network I The IP gives the home one IP address. The home network has multiple devices that need IP addresses. © 2013 Pearson 98

1. 29: DHCP in a Small Home Network II The access router DHCP circuit gives private IP addresses to other devices. © 2013 Pearson 99

1. 30: Network Address Translation (NAT) NAT allows multiple internal hosts to share a single external IP address. External sniffers cannot learn internal addresses. © 2013 Pearson 100

Into the Cloud Basic Network Concepts Packet Switching Internetworking Layers Internet Standards A Small Home Network © 2013 Pearson 101

This Chapter 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). © 2013 Pearson 102

The Next 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. © 2013 Pearson 103

© 2013 Pearson