SNS topics and subscriptions in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an SNS topic in AWS?

An SNS topic is like a message board where messages are posted. Subscribers can then receive these messages. It helps send notifications to many receivers at once.

beginner

What does a subscription in SNS do?

A subscription connects a receiver (like an email or phone) to an SNS topic. When a message is sent to the topic, all subscribers get the message.

beginner

Name two common protocols used for SNS subscriptions.

Two common protocols are Email and HTTP/HTTPS. Email sends messages to email addresses, HTTP/HTTPS sends messages to web servers.

intermediate

How does SNS ensure only confirmed subscriptions receive messages?

When you subscribe, SNS sends a confirmation message. The subscriber must confirm by clicking a link or responding. This prevents unwanted messages.

intermediate

What happens if a subscriber endpoint is unreachable in SNS?

SNS retries sending messages several times. If it still fails, the message can be sent to a dead-letter queue if configured, or it is dropped.

What is the main purpose of an SNS topic?

A To store data permanently

B To send messages to multiple subscribers

C To run code automatically

D To manage user permissions

SNS topics are used to send messages to many subscribers at once.

Which protocol is NOT supported by SNS subscriptions?

A FTP

B SMS

C HTTP

D Email

SNS does not support FTP as a subscription protocol.

What must a subscriber do to start receiving messages from an SNS topic?

A Create a new topic

B Delete the topic

C Confirm the subscription

D Send a message to the topic

Subscribers must confirm their subscription to receive messages.

If a subscriber's endpoint is down, what does SNS do?

A Stops sending messages forever

B Deletes the subscription immediately

C Sends messages to all other subscribers only

D Retries sending messages

SNS retries sending messages several times before giving up.

Which of these is a valid SNS subscription endpoint?

A An email address

B A database table

C A virtual machine

D An S3 bucket

SNS supports email addresses as subscription endpoints.

Explain how SNS topics and subscriptions work together to deliver messages.

Think of a newsletter mailing list.

Describe what happens when a subscriber endpoint is temporarily unreachable in SNS.

Imagine sending a letter to a closed mailbox.