Chapter 1: Networking Fundamentals ===================================== Networking Fundamentals Introduction to Networking Networking is how computers and devices talk to each other. Any time you: Browse the internet Send a text message Watch a video Play an online game Connect to Wi-Fi You are using a network. A network is simply two or more devices connected so they can share information. These devices can include: Computers Phones Tablets Servers Routers Printers Smart TVs Gaming consoles Networking allows devices to share: Data (files, messages, videos) Resources (printers, internet access) Services (websites, email, cloud storage) Without networking, every device would work alone and could not communicate with others. Why Networking Is Important Networking is important because modern life depends on it. Some key reasons networking matters: Businesses rely on networks to operate Schools use networks for learning Hospitals use networks for patient care Governments use networks for services The internet itself is one massive network Even at home, you likely have a network that connects: Your phone Your laptop Your TV Your game console All through your router. Basic Network Types There are different types of networks based on size and purpose. Local Area Network (LAN) ^^^^^^^^^^^^^^^^^^^^^^^^ A LAN is a small network in a limited area. Examples: A home network A school computer lab An office building LANs are usually: Fast Private Controlled by one person or organization Most LANs use Ethernet cables or Wi-Fi. Wide Area Network (WAN) ^^^^^^^^^^^^^^^^^^^^^^^ A WAN covers a large area. Examples: The internet A company network connecting offices in different cities WANs are usually: Slower than LANs More expensive Managed by service providers The internet is the largest WAN in the world. Metropolitan Area Network (MAN) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ A MAN covers a city or large campus. Examples: A university network A city-wide Wi-Fi system MANs are larger than LANs but smaller than WANs. Personal Area Network (PAN) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ A PAN is a very small network around one person. Examples: Bluetooth headphones connected to a phone A smartwatch connected to a phone PANs usually use Bluetooth or USB connections. Network Devices Networks are built using special hardware devices. Computer (Host) ^^^^^^^^^^^^^^^ A host is any device that sends or receives data. Examples: Laptop Phone Server Hosts have: A network interface (Wi-Fi or Ethernet) An IP address Network Interface Card (NIC) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ A NIC allows a device to connect to a network. It can be: Wired (Ethernet) Wireless (Wi-Fi) Every NIC has a MAC address, which is a unique hardware identifier. Switch ^^^^^^ A switch connects multiple devices in a LAN. It: Receives data Sends it only to the correct device Switches make networks faster and more efficient. Router ^^^^^^ A router connects different networks together. It: Connects your home network to the internet Decides where data should go Routers use IP addresses to move data between networks. Modem ^^^^^ A modem connects your network to your internet service provider (ISP). It: Translates signals between your ISP and your router Many home devices combine a modem and router into one unit. Access Point ^^^^^^^^^^^^ An access point provides wireless access to a wired network. It: Allows Wi-Fi devices to connect Extends wireless coverage How Data Moves on a Network Data does not move as one big piece. It is broken into small chunks called packets. Each packet contains: The data The source address The destination address Packets travel through the network and are reassembled at the destination. Packets ^^^^^^^ Packets are small for several reasons: Faster transmission Easier error checking Better network efficiency If one packet is lost, only that packet needs to be resent. IP Addresses An IP address is like a mailing address for a device. It tells the network: Who sent the data Where the data should go Without IP addresses, devices would not know how to find each other. IPv4 ^^^^ IPv4 addresses look like this:: 192.168.1.10 They are: 32 bits long Written in four numbers separated by dots Each number ranges from 0 to 255. IPv6 ^^^^ IPv6 addresses look like this:: 2001:0db8:85a3::8a2e:0370:7334 They were created because IPv4 addresses are running out. IPv6: Uses 128 bits Supports many more devices Private vs Public IP Addresses Private IP Addresses ^^^^^^^^^^^^^^^^^^^^ Private IPs are used inside local networks. Common private ranges: 192.168.0.0 – 192.168.255.255 10.0.0.0 – 10.255.255.255 These addresses are not reachable from the internet. Public IP Addresses ^^^^^^^^^^^^^^^^^^^ Public IPs are used on the internet. They are: Assigned by ISPs Globally unique Your router usually has one public IP. MAC Addresses A MAC address is a hardware address. It: Is built into the NIC Never changes Looks like:: 00:1A:2B:3C:4D:5E MAC addresses work at a lower level than IP addresses. Ports A port is like a door on a device. It tells the computer which application should receive the data. Examples: Web traffic: Port 80 (HTTP), Port 443 (HTTPS) Email: Port 25 Secure shell: Port 22 IP address + port = specific service on a device. Protocols A protocol is a set of rules. It defines: How data is sent How data is received How errors are handled All networking depends on protocols. Common Protocols TCP ^^^ TCP is reliable. It: Checks if data arrived Resends lost packets Keeps data in order Used for: Web browsing Email File transfers UDP ^^^ UDP is fast but not reliable. It: Does not check delivery Does not resend data Used for: Video streaming Online gaming Voice calls HTTP and HTTPS ^^^^^^^^^^^^^ These are used for websites. HTTP: Not secure Data is readable HTTPS: Encrypted Secure DNS ^^^ DNS turns names into IP addresses. Example: google.com → 142.250.190.14 Humans remember names better than numbers. The OSI Model The OSI Model explains networking in layers. It has 7 layers, from top to bottom. This model helps: Understand how networks work Troubleshoot problems OSI Layers Layer 7 – Application ^^^^^^^^^^^^^^^^^^^^^ What users interact with: Web browsers Email programs Layer 6 – Presentation ^^^^^^^^^^^^^^^^^^^^^^ Handles: Formatting Encryption Compression Layer 5 – Session ^^^^^^^^^^^^^^^^^ Manages: Connections Sessions between devices Layer 4 – Transport ^^^^^^^^^^^^^^^^^^^ Controls: TCP and UDP Data reliability Layer 3 – Network ^^^^^^^^^^^^^^^^^ Handles: IP addresses Routing Layer 2 – Data Link ^^^^^^^^^^^^^^^^^^ Handles: MAC addresses Switches Layer 1 – Physical ^^^^^^^^^^^^^^^^^^ Physical parts: Cables Signals Electrical pulses Cables and Media Ethernet Cables ^^^^^^^^^^^^^^^ Used for wired connections. Common types: Cat5e Cat6 They provide: Speed Reliability Fiber Optic Cables ^^^^^^^^^^^^^^^^^^ Use light instead of electricity. They: Are very fast Travel long distances Used by ISPs and large networks. Wireless Networking Wi-Fi allows devices to connect without cables. It uses radio waves. Wi-Fi Standards ^^^^^^^^^^^^^^^ Examples: 802.11n 802.11ac 802.11ax (Wi-Fi 6) Newer standards are: Faster More efficient Network Security Basics Security protects networks from attacks. Firewalls ^^^^^^^^^ A firewall controls traffic. It: Allows safe traffic Blocks dangerous traffic Routers often include firewalls. Encryption ^^^^^^^^^^ Encryption scrambles data. It: Protects privacy Prevents spying HTTPS uses encryption. Basic Troubleshooting Common steps: Check cables Restart devices Check IP addresses Use commands like ping Common Networking Commands ping ^^^^ Tests if a device is reachable. ipconfig / ifconfig ^^^^^^^^^^^^^^^^^^^ Shows IP information. tracert / traceroute ^^^^^^^^^^^^^^^^^^^^ Shows the path data takes. Conclusion Networking is the foundation of modern technology. By understanding: Devices IP addresses Protocols Networks You gain the ability to: Troubleshoot problems Build networks Learn advanced topics like cybersecurity This knowledge is the first step toward understanding how the internet and modern systems work. Networking Fundamentals Quiz ---------------------------------------------- Introduction to Networking What is a network? a. One computer by itself b. Two or more devices connected to share information c. A type of program d. A power cable Why Networking Is Important Why is networking important? a. It lets devices communicate and share information b. It only helps video games c. It replaces computers d. It only works at schools Basic Network Types What type of network is typically used in a home? a. WAN b. LAN c. MAN d. PAN Network Devices Which device connects different networks together? a. Switch b. Router c. NIC d. Access point How Data Moves on a Network Data is broken into small pieces called: a. Files b. Signals c. Packets d. Streams IP Addresses What is the main purpose of an IP address? a. To identify a device on a network b. To encrypt data c. To block traffic d. To store files Private vs Public IP Addresses Where are private IP addresses normally used? a. On the public internet b. Inside local networks c. Only on servers d. Only on routers MAC Addresses What best describes a MAC address? a. A temporary software setting b. A hardware address built into a device c. A public IP address d. A network password Ports What does a port number identify? a. A physical cable b. A network device c. A specific service or application d. A Wi-Fi signal Protocols What is a protocol? a. A networking cable b. A set of rules for communication c. A hardware device d. A type of network Common Protocols Which protocol is reliable and checks that data arrives correctly? a. UDP b. TCP c. HTTP d. DNS The OSI Model How many layers are in the OSI model? a. 4 b. 5 c. 6 d. 7 Cables and Media Which cable is commonly used for wired Ethernet networks? a. HDMI b. USB c. Ethernet (Cat5e/Cat6) d. Power cable Wireless Networking What does Wi-Fi use to transmit data? a. Light b. Sound c. Radio waves d. Electricity Network Security Basics What is the main purpose of a firewall? a. To speed up the network b. To control and block unwanted traffic c. To assign IP addresses d. To provide Wi-Fi Basic Troubleshooting Which command is commonly used to test if a device is reachable on a network? a. ipconfig b. tracert c. ping d. netstat Answer Key Introduction to Networking – b Why Networking Is Important – a Basic Network Types – b Network Devices – b How Data Moves on a Network – c IP Addresses – a Private vs Public IP Addresses – b MAC Addresses – b Ports – c Protocols – b Common Protocols – b The OSI Model – d Cables and Media – c Wireless Networking – c Network Security Basics – b Basic Troubleshooting – c