Full form: Transmission Control Protocol
Also known as: Transmission Control Protocol
Quick Definition
A Layer 4 connection-oriented protocol that guarantees reliable, ordered delivery.
TCP is a Layer 4 (Transport layer) protocol that provides reliable, ordered, and error-checked delivery of data between applications. It uses a three-way handshake (SYN, SYN-ACK, ACK) to establish a connection before data transfer. TCP uses sequence numbers, acknowledgements, and retransmission to ensure every byte arrives intact and in order. Common TCP-based protocols include HTTP, HTTPS, SSH, FTP, and SMTP.
When you load a web page, your browser opens a TCP connection to the server (port 443 for HTTPS). If a packet is lost in transit, TCP automatically retransmits it — ensuring the page loads completely.
TCP adds overhead compared to UDP because of its handshake and acknowledgement mechanism. Applications that prioritise speed over reliability (VoIP, DNS) typically use UDP instead.
TCP is a Layer 4 (Transport layer) protocol that provides reliable, ordered, and error-checked delivery of data between applications. It uses a three-way handshake (SYN, SYN-ACK, ACK) to establish a connection before data transfer. TCP uses sequence numbers, acknowledgements, and retransmission to ensure every byte arrives intact and in order. Common TCP-based protocols include HTTP, HTTPS, SSH, FTP, and SMTP.
TCP adds overhead compared to UDP because of its handshake and acknowledgement mechanism. Applications that prioritise speed over reliability (VoIP, DNS) typically use UDP instead.
When you load a web page, your browser opens a TCP connection to the server (port 443 for HTTPS). If a packet is lost in transit, TCP automatically retransmits it — ensuring the page loads completely.
TCP falls under the Network Fundamentals domain of the 200-301 exam. Understanding it in context with related terms like udp and port-security is essential for answering scenario-based questions correctly.