Three-way handshake in Computer Networks - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the three-way handshake in networking?

The three-way handshake is used to establish a reliable connection between two devices before data transfer begins. It ensures both sides are ready and agree on communication parameters.

beginner

Name the three steps involved in the three-way handshake.

1. SYN: The client sends a synchronization request.<br>2. SYN-ACK: The server acknowledges and sends its own synchronization.<br>3. ACK: The client acknowledges the server's response, completing the connection setup.

intermediate

Why is the three-way handshake important for TCP connections?

It helps synchronize sequence numbers and confirms both devices are ready, which prevents data loss and ensures reliable communication.

intermediate

What could happen if the three-way handshake is skipped?

Skipping the handshake can cause data to be sent before the connection is ready, leading to lost or corrupted data and unreliable communication.

beginner

In the three-way handshake, what does SYN and ACK stand for?

SYN stands for Synchronize, which is a request to start communication.<br>ACK stands for Acknowledgment, which confirms receipt of a message.

What is the first message sent in the three-way handshake?

A SYN-ACK

B ACK

C SYN

D FIN

The client starts the handshake by sending a SYN message to initiate the connection.

What does the server send in response to the client's SYN message?

A ACK

B SYN

C FIN

D SYN-ACK

The server replies with a SYN-ACK message to acknowledge the client's SYN and send its own synchronization.

Which protocol commonly uses the three-way handshake?

A TCP

B IP

C UDP

D HTTP

TCP uses the three-way handshake to establish reliable connections.

What is the main goal of the three-way handshake?

A To establish a reliable connection

B To send data

C To close a connection

D To encrypt data

The handshake sets up a reliable connection before data transfer.

What happens after the client sends the final ACK in the handshake?

A Connection is closed

B Connection is established and data transfer begins

C Server sends FIN

D Client waits for timeout

After the final ACK, both sides have agreed and the connection is ready for data transfer.

Explain the three steps of the three-way handshake and why each step is necessary.

Think about how two devices agree to communicate reliably.

Describe what could go wrong if the three-way handshake did not happen before data transfer.

Consider what happens if devices start talking without agreeing first.