Generally, TCP is a connection-oriented protocol. TCP requires a connection to be established before data transfer begins. The two hosts must synchronize their initial sequence numbers to establish a connection. Synchronization occurs through an exchange of segments that carry a synchronize (or SYN) control bit and the initial sequence numbers. This solution requires a mechanism that picks the initial sequence numbers and a handshake to exchange them.
The synchronization requires each side to send its own initial sequence number (or INS) and to receive a confirmation of exchange in an acknowledgment (or ACK) from the other side. Each side must also receive the ISN from the other side and send a confirming ACK in a a Cloud Hosting or a Website Hosting that has a Dedicated Server on it for example.