TCP

Lesson in the System Design Roadmap · Stage 15: Communication

Last updated 14 September 2026

What is TCP?

TCP (Transmission Control Protocol) is a connection-oriented, reliable, and ordered protocol used for transmitting data over an IP network. It establishes a connection between a sender and receiver before data transfer begins, ensures that data packets arrive in the correct sequence without errors, and provides mechanisms for retransmission of lost packets and flow control to manage network congestion.

Study this in the interactive course See the whole System Design roadmap

Free resources to learn TCP

Open sourceWhat Is TCP?
ArticleWhat is the difference between HTTP protocol and TCP protocol?
ArticleNetworking for game programming
ArticleKey differences between TCP and UDP protocols
ArticleDifference between TCP and UDP
ArticleTransmission control protocol
ArticleUser datagram protocol
ArticleScaling memcache at Facebook

TCP: common questions

Can I learn TCP in Hindi?

This lesson is written in English. Once you sign in, open it in the interactive course and ask the AI tutor to explain TCP in Hindi or Hinglish. The tutor answers from this lesson’s own text, so it stays on the syllabus, and it runs on your own Google, OpenAI or Anthropic key.

Is this TCP tutorial for beginners?

It is lesson 55 of 147 in the free System Design roadmap, in stage 15, Communication. If you are new to System Design, start from stage 1 and come back here in order; if you already know the earlier stages, this lesson stands on its own.