TCP vs UDP: When Each Is Used
Learn the difference between connection-oriented TCP and connectionless UDP and their security implications.
The Transport Layer
TCP and UDP are the two main protocols at the transport layer (OSI Layer 4). They define how data is sent between applications on different hosts.
TCP: Transmission Control Protocol
TCP is a connection-oriented protocol. Before data is sent, a connection is established via the three-way handshake. TCP guarantees delivery, ordering, and error checking.
Use cases: HTTP/HTTPS, SSH, SMTP, FTP — any application that needs reliability.
All lessons in this course
- IP Addressing and Subnets
- TCP vs UDP: When Each Is Used
- DNS: How Domains Resolve to IPs
- HTTP and HTTPS Basics