#readwise # Network Foundations - Network Concepts  ## Metadata - Author: [[Hack The Box]] - Full Title: Network Foundations - Network Concepts - URL: https://academy.hackthebox.com/module/289/section/3236 ## Summary Networking is essential for modern technology, connecting various devices and systems. The OSI and TCP/IP models help us understand how data is transmitted across networks. The OSI model has seven layers, while the TCP/IP model has four, simplifying the process for practical use. Common protocols like HTTP, FTP, and TCP ensure efficient data exchange and communication. ## Highlights When accessing a website, several layers of the TCP/IP model work together to facilitate the process. At the Application Layer, your browser utilizes HTTP to request the webpage. This request then moves to the Transport Layer, where TCP ensures the data is transferred reliably. The Internet Layer comes into play next, with IP taking charge of routing the data packets from our device to the web server. Finally, at the Network Interface Layer, the data is physically transmitted over the network, completing the connection that allows us to view the website. ([View Highlight](https://read.readwise.io/read/01jnvg4ydxvjsze7nbtbw81hkk)) ^pqxmhu --- In practical terms, the TCP/IP model is the backbone of network data transmission, actively employed across various networking environments. On the other hand, the OSI model, while not directly implemented, plays a crucial role as a comprehensive theoretical framework. It helps demystify the complexities of network operations, providing clear insights and a structured approach to understanding how networks function. Together, these models form a complete picture, bridging the gap between theoretical knowledge and practical application in networking. ([View Highlight](https://read.readwise.io/read/01jnvg5wwt6mt747tmjmyp899m)) ^8j3vhz --- Transmission modes define how data is sent between two devices. `Simplex` mode allows one-way communication only, such as from a keyboard to a computer, where signals travel in a single direction. `Half-duplex` mode permits two-way communication but not simultaneously; examples include walkie-talkies where users must take turns speaking. `Full-duplex` mode, used in telephone calls, supports two-way communication simultaneously, allowing both parties to speak and listen at the same time. ([View Highlight](https://read.readwise.io/read/01jnvg9mr7xey18jj3xsgg6q5s)) ---