TCP (Transmission Control Protocol)

Transmission Control Protocol, better known as TCP, is an internet protocol standard that lets devices exchange data over a network to provide a seamless online experience.

What is TCP?

TCP defines how to establish and maintain a network conversation through which application programs can exchange data. It’s a core protocol of the Internet Protocol Suite, operating at a higher level than the Internet Protocol (IP), another crucial part of the internet's framework.

TCP delivers an error-checked stream of bytes between active applications on hosts communicating through an IP network. It’s a connection-oriented protocol, which means a connection is established and maintained until the programs at each end have finished exchanging messages.

How does TCP work?

TCP works by breaking down the data sent by an application into smaller chunks, known as packets. These packets are then sent over the internet to the receiving application. TCP also ensures that these packets are reassembled in the correct order at the receiving end.

A key feature of TCP is its reliable delivery of data through a process called error checking. Each packet of data sent via TCP includes a checksum, which is a numerical value based on the data in the packet. The receiving application also calculates a checksum and compares it with the one included in the packet. If the two values match, the data has been successfully received. If not, TCP will automatically request that the data be sent again.

The role of TCP in the Internet Protocol suite

The Internet Protocol Suite, also known as TCP/IP, is the model for communications protocols used in the Internet and similar computer networks. TCP and IP are the two main protocols in this suite.

TCP ensures that the data sent from one device to another is delivered correctly. It does this by establishing a connection between the two devices and maintaining it until the data transfer is complete. On the other hand, IP is responsible for routing the data packets to the correct destination.

TCP vs. UDP

TCP is designed for reliable data transmission, while the User Datagram Protocol (UDP) is another protocol that’s faster but less reliable. Unlike TCP, UDP is a connectionless protocol. UDP doesn’t establish a connection before sending data, nor does it ensure that data packets arrive in the correct order.

As a connectionless protocol, UDP is often used for applications that prefer speed over reliability, like gaming or live streaming. However, TCP is better for applications that need reliable data delivery, such as web browsing or email.