TCP (Transmission Control Protocol)

TCP, short for Transmission Control Protocol, is one of the foundational protocols of the Internet Protocol Suite, commonly known as TCP/IP. It operates at the transport layer and is crucial for managing the delivery of data between computers over a network. TCP is often paired with the Internet Protocol (IP), which handles the routing of packets across network boundaries, making TCP/IP the basic communication language of the Internet.

The primary function of TCP is to provide reliable, ordered, and error-checked delivery of a stream of data between applications running on hosts communicating over an IP network. TCP achieves this reliability by establishing a connection between the sender and the receiver before data transmission begins. This connection is maintained throughout the session until all data has been successfully transmitted and acknowledged.

Key features of TCP include:

Because of these features, TCP is used for applications where data must arrive intact and in the correct order, such as web browsing, email, and file transfers. Its method of breaking down data into packets, sending them, and reassembling them at the destination allows for efficient transmission even over networks with high latency and packet loss.

However, the same features that ensure reliability can also introduce latency and overhead, making TCP less suitable for real-time applications such as voice over IP or online gaming. For these types of applications, protocols like UDP (User Datagram Protocol) might be preferred due to their lower latency, despite their lack of guaranteed delivery mechanisms.