WebSockets for real-time communication in Computer Networks - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a WebSocket?

A WebSocket is a communication protocol that provides a full-duplex, persistent connection between a client and a server, allowing real-time data exchange.

beginner

How does WebSocket differ from HTTP?

Unlike HTTP, which is request-response and stateless, WebSocket creates a continuous connection allowing both client and server to send data anytime without repeated handshakes.

beginner

What is the main advantage of using WebSockets for real-time communication?

WebSockets reduce latency and overhead by keeping the connection open, enabling instant data transfer which is ideal for chat apps, live updates, and games.

intermediate

What does 'full-duplex' mean in the context of WebSockets?

Full-duplex means data can be sent and received simultaneously between client and server over the same connection.

intermediate

What is the initial step to establish a WebSocket connection?

The client sends a WebSocket handshake request to the server over HTTP, which the server upgrades to a WebSocket connection if accepted.

Which protocol does WebSocket start with before upgrading the connection?

A SMTP

B HTTP

C FTP

D TCP only

WebSocket connections begin with an HTTP handshake request that upgrades the connection to WebSocket.

What type of communication does WebSocket provide?

A Broadcast only

B Half-duplex

C Simplex

D Full-duplex

WebSocket supports full-duplex communication, allowing simultaneous two-way data flow.

Which of these is a common use case for WebSockets?

A Live chat applications

B Static web pages

C Email sending

D File storage

Live chat apps need real-time updates, which WebSockets provide efficiently.

What happens if a WebSocket connection is closed?

A Connection switches to HTTP automatically

B Data continues to flow automatically

C Client and server must re-establish connection to communicate again

D Server sends data without client request

Once closed, the WebSocket connection must be reopened to resume communication.

Which layer of the internet protocol stack does WebSocket operate on?

A Application layer

B Transport layer

C Network layer

D Data link layer

WebSocket is an application layer protocol built on top of TCP.

Explain how WebSockets enable real-time communication between a client and a server.

Think about how WebSocket keeps the connection open and allows both sides to send data anytime.

Describe a real-life example where WebSockets improve user experience compared to traditional HTTP.

Consider apps like messaging or live sports scores.