Networking Basics: An Introduction Concept

Understanding the basics of networking is crucial for anyone involved in IT or related fields. Networking enables the seamless exchange of data and resources, forming the backbone of modern communication and information sharing. By familiarizing yourself with different types of networks, key components, and essential protocols, you can build a solid foundation for more advanced networking concepts.

1. Chapter Six Networking Fundamentals

2. Computer network A collection of computing devices that are connected in various ways in order to communicate and share resources or files Wired network: the connections between computers in a network are made using physical wires or cables Wireless network: the connections between computers in a network are made using radio waves or infrared signals 2

3. Computer network Each computer in the network is known as: node or host 3

4. Network Types

5. Network Types LAN

6. Network Types Local Area Network (LAN): two or more computers connected together, the computers are physically near each other (for example: in the same building) LANs are inexpensive to install LANs provide higher speeds 6

7. Network Types LAN WAN

8. Network Types Wide Area Network (WAN): is a connection of LAN s (for example : the Internet) WANs span a larger area than a single city. These use long distance telecommunication networks for connection, thereby increasing the cost. 8

9. Network Types LAN WAN PAN

10. Network Types LAN WAN PAN MAN

11. Network Types Metropolitan Area Network (MAN): usually span tens of kilometers (for example: in the same city ) The cost of installation and operation is higher. MANs use high-speed connections such as fiber optics to achieve higher speeds 11

12. The Internet It is a large group of computers that are connected to each other and used to send information quickly between computers around the world 12

13. Physical topology of a network

14. Physical topology of a network The term physical topology refers to the way in which a network is laid out physically. The topology of a network is the geometric representation of the relationship of all the links and linking devices There are four basic topologies possible: mesh, star, bus, and ring

15. Network Topologies Bus Star Ring Mesh Hybrid

16. Bus Network

17. Physical topology of a network Bus Topology A bus topology is multipoint connection. One long cable acts as a backbone to link all the devices in a network. Nodes are connected to the bus cable by drop lines and taps.

18. There is a limit on the number of taps a bus can support and on the distance between those taps. As a signal travels along the backbone, some of its energy is transformed into heat. Therefore, it becomes weaker and weaker as it travels farther and farther. The cable has two end terminals that dampen the signal so that it does not keep moving from one end of the network to the other

19. Bus Network

20. Physical topology of a network Advantage Simplest and easiest to install Single cable that runs to all computers which share the same data and address path Messages are sent to the same trunk, each computers check if the message is addressed to them. If yes, they receive it if not they ignore it until one accepts it Lowest cost Don’t exist today

21. Physical topology of a network Disadvantages Difficult to add a workstation; either reroute the cable or run 2 additional lengths If cable breaks the entire network is compromised Slower operations, as only one node transmits data at a time

22. Physical topology of a network Star Topology Each device has a dedicated point-to-point link only to a central controller. A star topology does not allow direct traffic between devices. The controller acts as an exchange: 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. The star topology is used in local-area networks (LANs)

23. Star Network

24. Physical topology of a network Star Topology Advantages: less expensive than a mesh topology, each device needs only one link and one I/O port to connect it to any number of others. Easy to install and reconfigure. Robustness, if one link fails, only that link is affected, all other links remain active. As long as the hub is working, it can be used to monitor link problems and bypass defective links

25. Physical topology of a network Star Topology Disadvantage: the dependency of the whole topology on one single point, the hub. If the hub goes down, the whole system is dead

26. Physical topology of a network Ring Topology Each device has a dedicated point-to-point connection with only the two devices on either side of it. A signal is passed along the ring in one direction, from device to device, until it reaches its destination. Each device in the ring incorporates a repeater. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along

27. Ring Network

28. Physical topology of a network Ring Topology Advantages: easy to install and reconfigure traffic considerations (maximum ring length and number of devices).

29. Physical topology of a network Ring Topology Disadvantages: Difficult to add new computers Network will go down if one of the computers (nodes) goes down Lack fault tolerance Don’t exist today

30. Physical topology of a network Mesh Topology In a mesh topology, every device has a dedicated point-to-point link to every other device. The term dedicated means that the link carries traffic only between the two devices it connects. The number of physical links in a fully connected mesh network with n nodes  n(n-1)/2 The mesh topology used in the connection of telephone regional offices in which each regional office needs to be connected to every other regional office.

31. Mesh Network

32. Physical topology of a network Mesh Topology Advantages: Each link can carry its own data load, thus eliminating the traffic problems that can occur with shared links. A mesh topology is robust. If one link becomes unusable, it does not incapacitate the entire system. Every message travels along a dedicated line, only the intended recipient sees it. Physical boundaries prevent other users from gaining access to messages. Disadvantage: The amount of cabling and the number of I/O ports required.

33. Mesh Network

34. Network Components

35. Network Components Servers Dedicated Non-dedicated

36. Servers Computers that work behind the scenes to provide(serve) the resources requested by the clients

37. Servers Computers that work behind the scenes to provide(serve) the resources requested by the clients Two types Non-dedicated - provides many different services to its client computers such as file retrieval, printing, and emailing. Dedicated - provides only one type of resource to its clients, such as printing

38. Network Components Servers Dedicated Non-dedicated Clients or workstations

39. Network Components Servers Dedicated Non-dedicated Clients or workstations Resources Printers, peripherals, disk storage and file access, applications

40. Network connection models Networks can also be classified according to the networked computers’ roles in the network’s operation.

41. Network connection models Networks can also be classified according to the networked computers’ roles in the network’s operation. Peer-to-peer, and server-based.

42. Network Resource Access Peer-to-peer

43. Network Resource Access Peer-to-peer Client-server

44. Network connection models Peer-to-peer network

45. Peer-to-peer networks are inexpensive and easy to install. They are popular as home networks and for use in small companies. Most operating systems come with built-in peer-to-peer networking capability.

46. The maximum number of peers that can operate on a peer-to-peer network is ten. Each peer shares resources and allows others open access to them. Shares can be document folders, printers, peripherals, and any other resource that they control on their computers.

47. Client-Server

48. The client-server relationship

49. How the Web Works? WWW use classical client / server architecture HTTP is text-based request-response protocol Page request Client running a Web Browser Server running Web Server Software (IIS, Apache, etc.) Server response HTTP HTTP

50. Client/Server There are two types of servers: File server A computer that stores and manages files for multiple users on a network Web server A computer that responds to requests for web pages (from the browser client) 50

51. Web servers  and  browsers web server : software that listens for web page requests Apache Microsoft Internet Information Server (IIS) ( part of Windows ) web browser : fetches/displays documents from web servers Mozilla Firefox Microsoft  Internet Explorer  (IE) Apple  Safari Google Chrome Opera 51

52. Introduction Network Protocol A protocol is a set of rules that governs the communications between computers on a network These rules include guidelines that regulate: the method of access , types of cabling and speed of size data transfer

53. The Most Common Protocols Are: Ethernet Local Talk Token Ring FDDI ATM Did you ever wonder what HTTP in web addresses was about?

54. The Most Common Protocols Are: Ethernet Local Talk Token Ring FDDI ATM Did you ever wonder what HTTP in web addresses was about? It stands HyperText Transfer Protocol

55. Ethernet Most widely used Uses an access method called CSMA/CD (Carrier Sense Multiple Access / Coll i sion Detect i on

56. What Does That Mean? Each computer i n the network 'listens' to the cable before sending anything through the network. If the network is clear , the computer wi l l transmit. If another computer is already transmitting on the cable , the computer will wait and try again when the line is clear

57. Ethernet (continued) A collision happens if two computers attempt to transmit at the same time. Each computer then backs off and waits a random amount of time before attempting to retransmit .It is normal to have collisions using this method, but the delays caused by collisions and transmissions is small , and does not effect speed of transmission on the network CSMA / CD = C arrier S ense M ultiple A ccess / C ollision D etection

58. Ethernet (continued) Ethernet protocol allows for data to be transmitted over twisted pair , coaxial or f i ber optic cable at a speed of 10 Mbps

59. Fast Ethernet To allow for faster transmission, the Ethernet protocol has developed a new standard that supports 100 Mbps Fast Ethernet requires the use of more expensive equipment and network cards

60. Gigabit Ethernet The Ethernet protocol has also developed a new standard that allows transmission of 1 Gbps (gigabit per second)

61. Local Talk Local Talk is a network protocol that was developed by Apple for Macintosh computers Local Talk uses the CSMA/CA Carrier Sense Multiple Access with Collision Avoidance It works in a similar way to CSMA/CD It is a lot slower than Ethernet (only 230 Kbps)

62. Token Ring Token ring protocol i nvolves 'token- pass . ing ' . It is not as popular as Ethernet protocol

63. FDDI Stands for Fiber Distributed Data Interface. Is used mainly to connect two or more LANs, often over large distances. Can operate over fiber optic cable at 100 Mbps.

64. ATM- Asynchronous Transfer Mode Transmit data at a speed of 155 Mbps and higher Works by transmitting all data in small packets of fixed size (other protocols transfer variable size packets) Like FDDI , is most often used to connect two or more LANs - .._J

65. Where does TCP/IP fit into all this? TCP/IP is the protocol that is used for the transmission of i nformation over the Internet IP (Internet Protocol) - the main delivery system for information over the Internet TCP (Transport Control Protocol) - used to break apart and rebuild information that travels over the Internet.

66. OSI Model

67. ** The above examples will be discussed in detail in Chapter 7

68. Cables and Connectors

69. Cables and Connectors Coaxial Twisted Pair Fiber

70. Coaxial Cable

71. Coaxial Cable Types RG # Popular Name Ethernet Implementation Type of Cable RG-6 Satellite/cable TV, cable modems N/A Solid copper RG-8 Thicknet 10Base5 Solid copper RG-58 U N/A None Solid copper RG-58 AU Thinnet 10Base2 Stranded copper RG-59 Cable television N/A Solid copper

72. Twisted Pair Cable

73. 568A/B Standards 568 B 568 A

74. Fiber Optic Cable Single-mode fiber (SMF) Multi-mode fiber (MMF)

75. Fiber Optic Connectors ST SC LC

76. Understanding IP Addressing Each device needs to have a unique IP address Any device with an IP address is referred to as a host As an administrator, you can assign the host’s IP configuration information manually, or you can have it automatically assigned by a DHCP server.

77. IPv4 It’s a 32-bit hierarchical address that identifies a host on the network e.g. 192.168.111.10 Each of the numbers in this example represents 8 bits (or 1 byte) of the address, also known as an octet. The numbers at the beginning of the address identify groups of computers that belong to the same network; IP is hierarchical and not flat.

78. Understanding Binary (see fig. 7.3) IP address is in 4 octets, in dotted decimal notation e.g. 192.168.111.120 A binary bit is a value with two possible states: on equals 1 and off equals 0 When you’re working with IPv4 addressing, all numbers will be between 0 and 255. If all of the bits in an octet are off, or 00000000, the corresponding decimal value is 0. If all bits in an octet are on, you would have 11111111, which is 255 in decimal.

79. Understanding Binary (see fig. 7.3) For example, 10000001 is equal to 129 (128 + 1), and 00101010 is equal to 42 (32 + 8 + 2). **Conversion from Binary to Decimal up to 255 is required

80. Parts of the IP Address Each IP address is made up of two components: the network ID and the host ID Neither the network ID nor the host ID can be set to all 0s Neither the network ID nor the host ID can be set to all 1s Computers are able to differentiate where the network ID ends and the host address begins through the use of a subnet mask . This is a value written just like an IP address and may look something like 255.255.255.0 When setting bits to 1 in a subnet mask, you always have to turn them on. Therefore if subnet mask 255.255.255.0 is used on IP 192.168.111.10, 192.168.111 is the Network ID and 10 is the host ID

81. IPv4 Address Classes

82. Class A First Octet 1-127 - PS: the first Octet determines the class Subnet Mask is 255.0.0.0 (8bits used for network portion and 24 bits for host) Using the formula 2 = 2 = 128 networks but because 0 and 127 are reserved = 126 Networks (first bit is 0 that’s why we use 7) Using the formula 2 -2 = 2 -2 = 16,777,214 network hosts/IP addresses available Address 127 is reserved and used as loopback address  

83. Class B  

84. Class C  

85. • DHCP

86. DHCP • Dynamic Host Configuration Protocol does not require an administrator to add an entry for a computer into the database. Instead DHCP is "plug - and - pla y " networld.ng. The computer runs a client to obtain configuration info from DHCP obtain a permanent address if the computer is nonmobile .

87. DHCP • DHCP uses permanent address that are assigned to server computers and a pool of addresses that are allocated on demand. Based on the computer's entry in the server's database, the DHCP decides the type of address to assign. For dynamic addresses, the computers IP may change with each boot .

88. DHCP Considerations • When a system reboots, there is a flood of DHCP requests. This is handled by using a random wait time before transmitting an address request. Caching allows the computer to save the DH CP server's address in a cache on a permanent storage, and 11se the cache information on reboot once it has been validated .

89. Lease • DHCP uses the concept of a "lease" or amount of time that a given IP address will be valid for a computer. The lease time can vary depending on ho w ' long a user is likely to require the Internet connection at a particular location. It's especially useful in education and other environments , where users change frequently. Using very short leases, DHCP can dynamically reconfigure networks in which there are more computers than there are available IP addresses

90. APIPA • Automatic Private IP Addressing, a feature starting ,vith Windows 98 If a DHCP client finds no DHCP server when it boots, it uses APIPA to automatically configure itself with an IP address from a range that has been reserved especially for Microsoft. The IP address range is 169.254.0.1 through 169.254.255.254. The client also configures itself with a default class B subnet mask of 255.255.0.0. A client uses the self- configured IP address until a DHCP server becomes available.

91. DHCP and DNS A DHCP server is configured to provide IP configuration information to clients automatically, in what is called a lease (not permanent). IP address, Subnet Mask, Default Gateway and DNS address are issued in the lease

92. DHCP ready Client sends DHCP DISCOVER requesting a DHCP server DHCP server return the above configuration Static IP address – entered by administrator

93. DHCP and DNS DNS has one function on the network, and that is to resolve hostnames to IP addresses Ping www.google.com gives an IP of 72.14.205.104. You type the www address instead of the IP. DNS matches or resolves the two On an intranet (local network), it resolves PC names to their IP addresses. It has a database with host-to IP data

94. Public vs Private IP Addresses Public - All of the addresses that are used on the Internet (unique world-wide) Private – Designed for private networks and are not routable to the internet (infinite) NAT (Network Address Translation) – Problem with globally non-unique private IP address means companies would have conflicts accessing the internet. NAT resolves this problem by translating non-routable private IP address into public IP addresses

95. APIPA Automatic Private IP Addressing (APIPA) is a TCP/IP standard used to automatically configure IP-based hosts that are unable to reach a DHCP server. If your cable gets disconnected you get an APIPA AKA zero configuration networking or address autoconfiguration TCP/IP network can run with no configuration at all – therefore devices with APIPA and on the same LAN can talk, share printers etc.

96. IPv6 IPv4 = 32 bit, 2 32 = 4GB or 4 billion addresses worth of combinations (7.8 billion people have surpassed this) We each have multiple individual devices with IP addresses IPv6 provides 128 bit addresses, 2 64 – Astronomical number of networks 16Billion Billion) Hexadecimal values; 4 binary bits (1111) makes a hexadecimal value

97. IPv6 Longer – 16-bit fields each with 4 hexadecimal separated by colons

98. Wired vs Wireless Similar in concept Wired hub, wired switch, wired router Wireless – router and access point (eventually wired) SSID – service set identifier, name of the network

99. CSMA/CA vs CSMA/CD Carrier Sense Multiple Access/Collision Avoidance ( Wireless) Carrier Sense Multiple Access/Collision Detection (Wired) back-off time – waiting period if collision occurs

100. Wireless Channels 2.4GHz and 5GHz

101. Wired vs Wireless Similar in concept Wired hub, wired switch, wired router Wireless – router and access point (eventually wired) SSID – service set identifier, name of the network

102. CSMA/CA vs CSMA/CD Carrier Sense Multiple Access/Collision Avoidance ( Wireless) Carrier Sense Multiple Access/Collision Detection (Wired) back-off time – waiting period if collision occurs

103. Wireless Channels 2.4GHz and 5GHz

104. 802.11 Standards 802.11a 802.11b 802.11g 802.11n 802.11ac

105. 802.11 Standards Standard Year Speed Frequency Modulation 802.11 1997 1Mbps-2Mbps 2.4Ghz FHSS or DSSS 802.11a 1999-2001 54Mbps 5Ghz OFDM 802.11b 1999 11Mbps 2.4GHz DSSS 802.11g 2003 54Mbps 2.4GHz OFDM or DSSS 802.11n 2010 600Mbps 2.4GHz & 5GHz OFDM or DSSS 802.11ac 2014 6900Mbps 5GHz OFDM

106. Wireless Encryption Methods WEP WPA WPA2

107. WEP Wired Equivalent Privacy It uses a static key The keys are commonly 10, 26, or 58 hexadecimal characters long WEP.64 -10-character key. WEP.128 – 26 characters, and WEP.256 uses 58

108. WPA Wi-Fi Protected Access Improvement to WEP Temporal Key Integrity Protocol (TKIP) – uses a 128-bit dynamic per-packet key. It generates a new key for each packet sent

109. WPA2 Wi-Fi Protected Access 2 Uses CCMP (Counter-Mode CBC-MAC) – Improvement to TKIP CCMP is based of federal Govt’s Advanced Encryption Standard (AES) Provides privacy, integrity and authentication

110. 802.11 Standards 802.11a 802.11b 802.11g 802.11n 802.11ac

111. 802.11 Standards Standard Year Speed Frequency Modulation 802.11 1997 1Mbps-2Mbps 2.4Ghz FHSS or DSSS 802.11a 1999-2001 54Mbps 5Ghz OFDM 802.11b 1999 11Mbps 2.4GHz DSSS 802.11g 2003 54Mbps 2.4GHz OFDM or DSSS 802.11n 2010 600Mbps 2.4GHz & 5GHz OFDM or DSSS 802.11ac 2014 6900Mbps 5GHz OFDM

112. Wireless Encryption Methods WEP WPA WPA2

113. WEP Wired Equivalent Privacy It uses a static key The keys are commonly 10, 26, or 58 hexadecimal characters long WEP.64 -10-character key. WEP.128 – 26 characters, and WEP.256 uses 58

114. WPA Wi-Fi Protected Access Improvement to WEP Temporal Key Integrity Protocol (TKIP) – uses a 128-bit dynamic per-packet key. It generates a new key for each packet sent

115. WPA2 Wi-Fi Protected Access 2 Uses CCMP (Counter-Mode CBC-MAC) – Improvement to TKIP CCMP is based of federal Govt’s Advanced Encryption Standard (AES) Provides privacy, integrity and authentication

116. Selected IEEE Standards 802.2 Logical Link Control (LLC) 802.3 CSMA/CD (Ethernet) LAN 802.5 Token Ring LAN 802.6 Metropolitan Area Network 802.11 Wireless Networking

117. Selected IEEE Standards 802.2 Logical Link Control (LLC) 802.3 CSMA/CD (Ethernet) LAN 802.5 Token Ring LAN 802.6 Metropolitan Area Network 802.11 Wireless Networking

118. Network Interface Cards Compatibility Performance Sending and controlling data Configuration Drivers

119. Network Interface Cards Compatibility Performance Sending and controlling data Configuration Drivers

120. Connectivity Devices Modem Access point Repeater and extender Hub

121. Connectivity Devices (continued) Patch panel Bridge Switch Router

122. Auxiliary Devices Ethernet over Power Power over Ethernet