TCP vs UDP: Difference and Comparison

The transfer of all data on the Internet between devices occurs through special "transport" protocols. Protocols process and deliver information (messages, photos, videos, etc) from one computer to another. The most popular transport layer protocols are TCP and UDP.

They both perform their task but differ in reliability and principle of operation. Let's see how they differ and which protocol to choose.

What is TCP

TCP is a transport channel that must be connected to all parties to transfer data. Only in a such way can it deliver information from point A to point B.

Benefits of TCP

• Reliability. TCP initiates communication through three stages and controls the transfer of data at all levels. If the information did not reach the recipient, the sender receives an error notification. This is why the TCP protocol is considered to be the guarantor of high-quality data delivery.
• Order preservation of delivery. Data packets arrive at point B in the same sequence and format in which they were sent. There is no such feature in UDP.
• Large volumes of information. This protocol delivers files of almost any size, and the quality of the connection will not deteriorate in any way.

Disadvantages of TCP

• Due to careful checks and processing, the data transfer rate is reduced. Delivery takes longer than UDP.

What is UDP

UDP is a protocol that works without establishing a connection with the parties. This is a simplified version of data transfer, without delivery guarantees.

Benefits of UDP

• Transmission speed. UDP doesn't bother with checks and process control, so it delivers data faster than TCP. If a file is lost along the way, it is reset automatically.

Disadvantages of UDP

• There are no guarantees for a successful data transfer. Information is delivered without checks, some datagrams may be lost during transmission.
• The order of the data is not followed. Point B may receive information in an inconsistent order.

What to choose: TCP or UDP

Although TCP outperforms UDP in reliability and transmission guarantees, both of these protocols are actively used by developers. It all depends on what you need the transport protocol for.

TCP is used for programs based on the transfer of messages and files: instant messengers, email applications, file hosting, and storage.

The UDP protocol is used for programs and web resources that broadcast audio or video files in real-time: online games, Internet TV, or video call programs. That is why sometimes the quality of sound and video deteriorates if the connection is lost during a conversation on the network.