2
5
3
4
Answer is Wrong!
Answer is Right!
The correct answer is C. There are 3 message types in CoAP:
- CON (confirmed request)
- ACK (acknowledgement)
- RST (reset)
A CON message is a request message that expects an ACK message in response. An ACK message is a response message that acknowledges the receipt of a CON message. A RST message is a message that indicates that the receiver of a message is not able to process the message.
CoAP is a lightweight, RESTful application protocol for constrained devices and low-power networks. It is designed to be efficient and reliable in resource-constrained environments. CoAP is an IETF standard (RFC 7252).