03. TCP 3-Way Handshake

1. Client -> Server: SYN
   • Contains a random initial sequence number (ISN), let's say Seq=X.
   • "I'd like to start a conversation. I'll start numbering my bytes at X."
2. Server -> Client: [SYN, ACK]
   • The server receives the request.
   • Contains its own random initial sequence number (Seq=Y) and acknowledges the client's number by setting the acknowledgment field to one more than what it received (Ack=X+1).
   • "I hear you! I'll start my bytes at Y, and I'm ready for your byte X+1."
3. Client -> Server: ACK
   • Acknowledges the server's sequence number (Ack=Y+1).
   • "I got your message. Let's talk." At this point, the connection is established, and data transfer can begin.

Graceful connection release: