TCP/IP, which stands for Transmission Control Protocol/Internet Protocol, is a suite of communication protocols that form the backbone of the Internet and many private networks. It provides a standardized set of rules to enable different types of computers, devices, and networks to communicate with each other over various physical mediums.
The TCP/IP protocol suite is divided into layers, each responsible for specific aspects of communication. The two main protocols, TCP and IP, operate at different layers of this model.
Now that we've discussed what TCP/IP is, let's go over what layers are involved. Similar to the OSI 7-layer model, TCP/IP also has a set of layers that can be divided into four sections.
Link Layer: This layer is responsible for the physical connection between devices like NICs (Network Interface Cards) and the cables that connect them to the same local network. It is responsible for the transmission and reception of raw data frames over a physical connection. An example would be connecting the ethernet cable from your PC to your router.
Internet Layer: The IP (Internet Protocol) operates in this layer. IP is responsible for addressing and routing packets of data so that they can travel across networks and arrive at the correct destination. The data is fragmented, broken down into smaller packets, and reassembled by the sending and receiving routers respectfully.
Transport Layer: The transport layer provides communication between devices on different hosts. It includes protocols such as TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). TCP ensures reliable, connection-oriented communication, while UDP is used for connectionless communication where speed is prioritized over reliability. What does connection-oriented communication mean? It's a networking paradigm where a reliable and ordered connection is established between 2 devices BEFORE data is exchanged. It ensures that there will be no interruption and the integrity of data will be held intact. An example of TCP is sending a file transfer, which utilizes FTP (File Transfer Protocol) and SCP (Secure Copy Protocol) ensuring that files are transmitted accurately without data loss or corruption. UDP on the other hand, is a connectionless protocol. This means that the transfer of data between devices does not rely on a solid connection and some data loss or corruption may occur. UDP is often used in real-time applications where low latency is more critical than guaranteed delivery. Why would this be a good thing? Think about the popular voice chat app "Discord," can you imagine how resource-intensive and slow the voice chat would be if your devices relied on a connection-oriented protocol like TCP? It would take ages to get sent and receive a simple "hello." Because UDP prioritizes speed over guaranteed delivery, we can have fast communication over voice chat if we want. Albeit, sometimes we might get connection drops which can be annoying too, but worth the faster response time of our friends and family.
Application Layer: This is the topmost layer that contains protocols that directly interact with software applications. This layer enables software applications on different dives to exchange data and information. Some common protocols include HTTP (Hypertext Transfer Protocol), SMTP (Simple Mail Transfer Protocol), FTP (File Transfer Protocol), and DNS (Domain Name System). The application layer allows for end-users to interact with the applications they want to use. An example is "https://www.google.com". The application layer is also responsible for formatting data for presentation to the user and ensuring that data is exchanged between applications. It provides mechanisms for data encryption and decryption to ensure secure communication.
To recap, TCP/IP is a foundational technology for networking, enabling communication between diverse devices and networks. It plays a crucial role in the functioning of the internet as we know it.
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