Computer Networking Basics

Computer networking refers to the process of connecting devices to share resources, exchange data, and communicate with each other. A typical computer network consists of various devices, including hosts, intermediate devices, and network interface cards (NICs).

Types of Devices in a Computer Network

Hosts

• Desktop Computers: These are personal computers designed for use in a fixed location.
• Laptops: These are portable computers designed for use in various locations.
• Mobile Devices: These include smartphones, tablets, and other handheld devices.
• Servers: These are specialized computers that provide services or resources to other devices on the network.

Intermediate Devices

• Routers: These devices connect multiple networks together and manage data transmission between them. (Layer 3: Network Layer)
• Switches: These devices connect multiple devices within a network and manage data transmission between them. (Layer 2: Data Link Layer)
• Firewalls: These devices provide security for a network by controlling incoming and outgoing traffic. (Layer 3/4: Network/Transport Layer)
• Modems: These devices connect a network to the internet via a broadband connection. (Layer 1: Physical Layer)

Network Interface Cards (NICs)

• Wired NICs: These connect devices to a network via a physical cable. (Layer 1: Physical Layer)
• Wireless NICs: These connect devices to a network wirelessly, using radio waves or infrared signals. (Layer 1: Physical Layer)
• Virtual NICs: These are software-based NICs that allow virtual machines to connect to a network. (Layer 2: Data Link Layer)

Network Configurations

• Local Area Networks (LANs): These are networks that connect devices in a limited geographical area, such as a home, office building, or campus.
• Wide Area Networks (WANs): These are networks that connect devices over a larger geographical area, such as a city, country, or even globally.
• Wireless Networks (WLANs): These are networks that connect devices wirelessly, using radio waves or infrared signals.
• Virtual Private Networks (VPNs): These are networks that use encryption and other security measures to create a secure, private connection between devices over the internet.

Network Architectures

• Client-Server Architecture: In this model, one device (the server) provides services or resources to other devices (the clients) on the network.
• Peer-to-Peer Architecture: In this model, all devices on the network act as both clients and servers, sharing resources and services with each other.
• Hybrid Architecture: This model combines elements of client-server and peer-to-peer architectures, allowing for flexibility and scalability in network design.

Network Layers (OSI Model)

• Layer 1: Physical Layer: Defines the physical means of data transmission, such as cable specifications and wireless transmission protocols.
• Layer 2: Data Link Layer: Provides error-free transfer of data frames between two devices on the same network.
• Layer 3: Network Layer: Routes data between different networks, using logical addresses (IP addresses) to identify devices.
• Layer 4: Transport Layer: Provides reliable data transfer between devices, using protocols such as TCP and UDP.
• Layer 5: Session Layer: Establishes, manages, and terminates connections between applications running on different devices.
• Layer 6: Presentation Layer: Converts data into a format that can be understood by the receiving device.
• Layer 7: Application Layer: Provides services and interfaces for applications to communicate with each other.