Networking Basics
Networking forms the backbone of modern communication and technology, allowing devices and systems to communicate and share data. This article explores the fundamental aspects of networking, which are essential for any high-level system design course, supplemented with real-world examples.
Layers of Communication Protocols and Their Functions
Understanding the layers of communication protocols is crucial. These layers, structured in models like the OSI and TCP/IP, help in managing complex networking processes.
OSI Model
The OSI Model's seven layers each have a distinct function:
Physical Layer
Manages the physical transmission of data. For example, it deals with the cables, switches, and other hardware that form the physical network.
Data Link Layer
Ensures node-to-node data transfer. Ethernet and Wi-Fi protocols operate at this layer.
Network Layer
Handles the routing of data. Routers work at this layer, directing traffic based on IP addresses.
Transport Layer
Ensures end-to-end communication reliability. Protocols like TCP (used for reliable web browsing) and UDP (used for streaming media) operate here.
Session Layer
Manages connections between applications, like establishing a VPN tunnel.
Presentation Layer
Translates data formats, like encrypting data for secure transmission.
Application Layer
Interfaces with applications; HTTP for web browsing and SMTP for email are examples.
TCP/IP Model
The TCP/IP model simplifies networking into four layers:
Link Layer
Combines physical and data link functions, dealing with hardware and local network traffic.
Internet Layer
Equivalent to the OSI's network layer, managing IP addressing and routing.
Transport Layer
Similar to OSI's, overseeing reliable data transmission.
Application Layer
Includes functions of the OSI's top three layers, directly interfacing with user applications.Each layer plays a distinct role, ensuring efficient and secure data transmission.
IP Addressing and Subnetting
IP addressing is essential for device identification and location on a network.
IPv4
Uses a 32-bit address scheme, limited to about 4 billion addresses. A home router typically assigns IPv4 addresses to devices on a local network.
IPv6
With a 128-bit scheme, it greatly expands the address space. IPv6 is increasingly used by internet service providers to accommodate more devices.
Subnet Masks and CIDR Notation
Subnet Masks
Define network and host portions of an IP address. In a typical home network, the subnet mask 255.255.255.0 is common, separating the network and device addresses.
CIDR Notation
A flexible way to allocate addresses. The notation /24, common in small business networks, indicates a subnet mask of 255.255.255.0.
These concepts are crucial in both small-scale (like home networks) and large-scale (like corporate or ISP networks) environments for efficient IP management.