Multiplayer in Web Games: WebSockets and Real-Time Quiz Quiz

Explore the core concepts behind multiplayer web games, focusing on how WebSockets enable real-time interactions and seamless quiz gameplay. This quiz tests your understanding of protocols, synchronization, latency handling, and core multiplayer architecture ideal for web-based quizzes.

1. WebSocket Protocol Basics

   Which feature distinguishes the WebSocket protocol from traditional HTTP when used in a real-time multiplayer quiz game?

   1. WebSockets allow persistent, bidirectional communication between client and server.
   2. WebSockets limit data transfer to textual information only.
   3. HTTP can push updates to multiple clients simultaneously.
   4. HTTP provides lower latency than WebSockets during gameplay.

   Explanation: WebSockets establish a persistent, bidirectional connection that is essential for real-time multiplayer interactions in web games. Unlike HTTP, which is stateless and unidirectional, WebSockets enable continuous data flow between clients and servers. The statement about HTTP pushing updates is incorrect, as it primarily uses request-response cycles. WebSockets support both binary and textual data, not just text. Finally, HTTP generally suffers from higher latency compared to WebSockets, making WebSockets superior for real-time scenarios.

2. Synchronization Challenge

   In a web-based real-time quiz game, how can synchronization of question display be best achieved among all players?

   1. Broadcasting the question with a timestamp via WebSocket to all clients.
   2. Using asynchronous HTTP POST requests to deliver questions.
   3. Relying on each client's internal clock for question timing.
   4. Polling the server every second for the next question using HTTP GET.

   Explanation: Broadcasting the question via WebSocket ensures immediate, simultaneous delivery to all players and, with a timestamp, helps synchronize start times, minimizing delay. Individual client clocks can vary, causing desynchronization. HTTP POST is meant for sending data to the server, not distributing content. Polling with HTTP GET increases latency and server load, making real-time synchronization unreliable.

3. Latency Management

   If some players experience network lag during a live quiz, which strategy most effectively ensures fairness?

   1. Including a buffer delay before displaying each question to all players.
   2. Reducing the question timer for users with high ping.
   3. Allowing faster clients to answer before slower ones see the question.
   4. Letting players refresh their browsers to fix lag.

   Explanation: Buffering by introducing a short delay before showing each question helps compensate for network lags, giving all players an equal chance to respond. Allowing fast clients to answer first is unfair to those with slower connections. Reducing timers for high-ping users penalizes them further. Refreshing the browser is unlikely to consistently solve latency or fairness issues.

4. Scalability in Multiplayer Architecture

   What is a recommended approach to scaling a real-time multiplayer web quiz to support many concurrent users?

   1. Running all player connections through a single central server.
   2. Using synchronous HTTP requests for each user action.
   3. Storing player states only on individual browsers.
   4. Distributing game sessions across multiple WebSocket server instances.

   Explanation: Distributing sessions among multiple servers allows the system to handle higher loads and more concurrent users efficiently. A single central server can't scale well and may become a bottleneck. Storing states only on browsers risks data loss and lack of coordination. Synchronous HTTP requests are not suitable for real-time, high-scale multiplayer interactions.

5. Quiz Game State Consistency

   During a multiplayer quiz session, what technique helps maintain consistent game state among all players in a room?

   1. Using the server as the single source of truth and broadcasting updates via WebSocket.
   2. Relying on scheduled emails to send state changes to all players.
   3. Syncing state via browser cookies on every answer.
   4. Allowing each client to manage its own independent version of the game state.

   Explanation: Designating the server as the central authority and broadcasting real-time updates via WebSocket ensures all players receive consistent and coordinated game state. Letting each client manage its own state risks inconsistencies and cheating. Browser cookies are not designed for real-time state syncing and are too slow. Emails are unsuitable for live state updates due to their sluggish and unreliable delivery speed.