Introduction to Computer Networking

• Computer networking connects two or more computing devices, thus facilitating communication and resource sharing.
• It allows users to share files, printers, and internet connections, as well as enabling centralized data storage and access.
• Networks range in size and complexity, from small home networks to large enterprise networks and the global internet.

Network Protocols

• Network protocols are sets of rules governing communication between devices on a network.
• They define how data is formatted, transmitted, received, and interpreted.
• Key protocols include TCP/IP, HTTP, DNS, and Ethernet.
• TCP/IP (Transmission Control Protocol/Internet Protocol) is the internet's foundation, providing reliable data transmission via packet switching.
• HTTP (Hypertext Transfer Protocol) facilitates web browsing, enabling communication between web browsers and servers.
• DNS (Domain Name System) translates domain names (e.g., google.com) into IP addresses, simplifying access to online resources.
• Ethernet is a common protocol for local area networks (LANs), defining the physical and data link layers.
• Protocols operate at different layers of the OSI (Open Systems Interconnection) model, each with specific functions.
• The OSI model includes seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.
• Each layer provides services to the layer above and receives services from the layer below.

IP Addressing

• IP addresses are unique numerical labels assigned to each device on a network, enabling communication.
• IPv4 addresses are 32-bit and written in dotted decimal notation (e.g., 192.168.1.1).
• IPv6 addresses are 128-bit, written in hexadecimal notation, and designed to replace IPv4 due to its limited address space.
• IP addresses facilitate the routing of data packets between devices on a network.
• Subnetting divides a network into smaller subnetworks, thus improving network efficiency and security.
• A subnet mask identifies the network and host portions of an IP address.
• Public IP addresses are used for internet communication and are assigned by internet service providers (ISPs).
• Private IP addresses are used within private networks and are not directly routable on the internet.
• Network Address Translation (NAT) translates private IP addresses to public IP addresses, enabling internet access for devices on a private network via a single public IP address.
• Dynamic Host Configuration Protocol (DHCP) automatically assigns IP addresses to devices on a network, simplifying network administration.

Wireless Networking

• Wireless networking allows devices to connect to a network without physical cables, using radio waves for data transmission.
• Wi-Fi (Wireless Fidelity) is the most common wireless networking technology, based on IEEE 802.11 standards.
• Wireless networks use access points (APs) to provide network access to wireless devices.
• Wireless security protocols, such as WPA2 and WPA3, encrypt wireless communication and protect against unauthorized access.
• Wireless channels and frequencies are used to avoid interference between different wireless networks.
• Wireless range is affected by obstacles, distance, and interference.
• Mesh networks extend wireless coverage by creating a network of interconnected nodes that relay data.
• Bluetooth is a short-range wireless technology for connecting devices like headphones, keyboards, and mice.
• Wireless networking provides flexibility and mobility but can be less secure and have lower bandwidth compared to wired networks.

Network Security

• Network security protects network infrastructure and data from unauthorized access, use, disclosure, disruption, modification, or destruction.
• Firewalls control network traffic and block unauthorized access.
• Intrusion detection systems (IDS) and intrusion prevention systems (IPS) monitor network traffic for malicious activity and take automated actions.
• Virtual Private Networks (VPNs) create secure, encrypted connections over public networks for secure remote access to private networks.
• Encryption protects sensitive data by converting it into an unreadable format.
• Antivirus software and malware protection detect and remove malicious software from network devices.
• Access control lists (ACLs) control user or device access to specific network resources.
• Network segmentation divides a network into isolated segments to limit the impact of security breaches.
• Regular security audits and vulnerability assessments identify and address security weaknesses.
• Security awareness training educates users about potential security threats and best practices.

Routing and Switching

• Routing and switching are fundamental functions in computer networks, enabling data forwarding between devices and networks.
• Routers forward data packets between different networks based on destination IP addresses.
• Routing protocols like OSPF and BGP exchange routing information between routers to determine optimal data paths.
• Switches forward data packets within a local area network (LAN) based on destination MAC addresses.
• Layer 2 switches operate at the data link layer, forwarding traffic based on MAC addresses.
• Layer 3 switches operate at the network layer, forwarding traffic based on IP addresses and performing routing functions.
• Virtual LANs (VLANs) logically segment a physical network into multiple broadcast domains, improving network performance and security.
• Spanning Tree Protocol (STP) prevents loops in a switched network by disabling redundant paths.
• Quality of Service (QoS) mechanisms prioritize network traffic, ensuring adequate bandwidth and low latency for critical applications.
• Routers and switches are essential components of network infrastructure, which enables efficient and reliable communication between devices and networks.