Real-time features in HLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are real-time features in system design?

Real-time features allow a system to process and deliver information instantly or with minimal delay, enabling immediate interaction or updates.

beginner

Name two common protocols used for real-time communication.

WebSocket and MQTT are common protocols that support real-time communication by maintaining persistent connections for instant data exchange.

intermediate

Why is low latency important in real-time systems?

Low latency ensures that data is delivered quickly, which is crucial for user experience in applications like chat, gaming, or live updates.

intermediate

What role does message broker play in real-time features?

A message broker routes messages between services or clients, enabling scalable and reliable real-time data delivery.

intermediate

Explain the difference between polling and push-based real-time updates.

Polling repeatedly asks the server for updates, causing delays and overhead. Push-based updates send data instantly from server to client when changes occur, improving efficiency.

Which protocol is best suited for maintaining a persistent real-time connection?

A WebSocket

B HTTP/1.1

C FTP

D SMTP

WebSocket keeps a persistent connection open for instant two-way communication, unlike HTTP which is request-response.

What is the main disadvantage of polling for real-time updates?

A Requires special hardware

B High latency and unnecessary server load

C Only works on mobile devices

D Does not support encryption

Polling causes delays and wastes resources by repeatedly asking the server even when no new data is available.

Which component helps scale real-time messaging by routing messages efficiently?

A Database

B Load balancer

C Message broker

D Cache

Message brokers manage message delivery between clients and services, enabling scalable real-time communication.

Why is low latency critical in real-time systems?

A To improve offline access

B To reduce storage costs

C To increase battery usage

D To ensure fast and smooth user experience

Low latency means data arrives quickly, which is essential for interactive applications like chat or gaming.

Which technology is commonly used for real-time updates in web browsers?

A WebSocket

B SMTP

C FTP

D Telnet

WebSocket is widely supported in browsers for real-time two-way communication.

Describe how real-time features improve user experience in a chat application.

Think about how messages appear immediately without refreshing.

Explain the architecture components needed to build a scalable real-time notification system.

Consider how messages flow from server to many users quickly.