Definition of Transmission Control Protocol (TCP) in Network Encyclopedia.
What is Transmission Control Protocol (TCP)?
Transmission Control Protocol, or TCP, is a transport layer protocol that enables reliable, connection-oriented network communication.

How It Works
Transmission Control Protocol (TCP) is a connection-oriented protocol that guarantees data will be delivered intact to its destination. TCP first establishes a session by using a TCP three-way handshake with TCP ports on each host. It then transmits the data in packets, each with a sequence number. When packets are received at their destination, TCP generates an acknowledgment to the sending host. If a packet in a sequence is not received, TCP on the sending host retransmits the packet after a certain interval of time.
Microsoft’s implementation of TCP on Windows platforms includes advanced features such as self-tuning to ensure that data is sent at a speed optimal for the receiving host, dead gateway detection, and checksums for ensuring error-free delivery.