What is the TCP three-way handshake and why is it used?

Prepare for the 241 Computer Science Certification Exam with comprehensive flashcards and multiple choice questions. Enhance knowledge with explanations and hints to excel in your test journey!

Multiple Choice

What is the TCP three-way handshake and why is it used?

The TCP three-way handshake is the process used to open a TCP connection so that data can be sent reliably. It makes sure both sides are ready and that they agree on initial sequence numbers, which are essential for tracking and ordering the data that will be exchanged. First, the client sends a synchronization message (SYN) to indicate it wants to start a connection and to propose its own initial sequence number. Next, the server responds with a synchronization-acknowledgment message (SYN-ACK), acknowledging the client’s request and providing its own initial sequence number. Finally, the client sends a plain acknowledgment (ACK) to confirm receipt of the server’s response. Once this exchange finishes, the connection is established and data can flow with reliable, in-order delivery. This is why the option describing the handshake as SYN, SYN-ACK, ACK and noting that it establishes a reliable connection and synchronizes sequence numbers is the best fit. The other options describe termination, an incorrect message order, or unrelated concepts like encryption, which don’t reflect how TCP actually opens a connection.

The TCP three-way handshake is the process used to open a TCP connection so that data can be sent reliably. It makes sure both sides are ready and that they agree on initial sequence numbers, which are essential for tracking and ordering the data that will be exchanged.

First, the client sends a synchronization message (SYN) to indicate it wants to start a connection and to propose its own initial sequence number. Next, the server responds with a synchronization-acknowledgment message (SYN-ACK), acknowledging the client’s request and providing its own initial sequence number. Finally, the client sends a plain acknowledgment (ACK) to confirm receipt of the server’s response. Once this exchange finishes, the connection is established and data can flow with reliable, in-order delivery.

This is why the option describing the handshake as SYN, SYN-ACK, ACK and noting that it establishes a reliable connection and synchronizes sequence numbers is the best fit. The other options describe termination, an incorrect message order, or unrelated concepts like encryption, which don’t reflect how TCP actually opens a connection.

More practice questions