TCP
Definition
Transmission Control Protocol - ensures reliable, ordered delivery of data over networks, making it essential for applications requiring accuracy.
Use Cases
- Cloudflare: Serving websites and APIs reliably over HTTPS (which runs over TCP) through a global edge network — Cloudflare terminates and proxies TCP connections at edge data centers, maintaining reliable client-to-edge and edge-to-origin TCP sessions for web traffic. (Improved reliability and performance for web delivery by handling connection management at the edge and providing consistent, ordered delivery for HTTP(S) traffic.)
- GitHub: Secure code repository access and operations over SSH and HTTPS — GitHub uses TCP-based protocols (SSH over TCP port 22 and HTTPS over TCP port 443) to ensure reliable, ordered transfer of repository data during clone, fetch, and push operations. (Reliable code transfers and consistent user experience for developers performing source control operations over the Internet.)
- Netflix: API calls and control-plane communication between microservices — Netflix’s services commonly communicate using HTTP/HTTPS (TCP-based) for many internal and external API interactions where reliable delivery and ordered data streams are required. (Dependable service-to-service communication for many request/response workflows, supporting consistent application behavior at scale.)
Frequently Asked Questions
- What's the difference between TCP and UDP?
- TCP is connection-oriented and focuses on reliability: it establishes a connection, retransmits lost packets, delivers data in order, and uses flow/congestion control. UDP is connectionless and does not guarantee delivery or ordering; it’s often used when low latency matters more than perfect reliability (for example, live voice/video or some gaming traffic).
- When should I use TCP?
- Use TCP when your application needs reliable, ordered delivery—such as web browsing (HTTP/HTTPS), file transfers, email, SSH remote access, and most database connections. Choose TCP when correctness matters more than the lowest possible latency and when you want the protocol to handle retransmissions and ordering for you.
- How much does TCP cost?
- TCP itself is free—it's a standard protocol. Costs come from the infrastructure that carries TCP traffic: cloud data transfer (egress/ingress), load balancers or NAT gateways, firewall processing, and compute resources used by your applications. Pricing depends on bandwidth, number of connections, and which managed networking components you use.
Category: networking
Difficulty: intermediate
Related Terms
See Also