What are the default port numbers used by MQTT for unencrypted and SSL/TLS encrypted communications, respectively?
Port 1883 is standard plain MQTT; Port 8883 is MQTT over TLS/SSL.
In MQTT Quality of Service (QoS) levels, what does 'QoS 2' guarantee?
QoS 0 = At most once; QoS 1 = At least once; QoS 2 = Exactly once delivery (guaranteed zero duplicate messages via PUBLISH/PUBREC/PUBREL/PUBCOMP).
CoAP (Constrained Application Protocol) is designed based on REST architecture (GET, POST, PUT, DELETE). Which transport protocol does CoAP use by default?
CoAP (RFC 7252) uses UDP (default port 5683) to keep overhead extremely low on constrained microcontrollers.
Which data serialization format is commonly paired with CoAP due to its ultra-compact binary representation compared to JSON?
CBOR (RFC 7049) provides binary data encoding that requires significantly fewer bytes than plain JSON, perfect for low-bandwidth CoAP networks.
What routing protocol is specifically designed by IETF (RFC 6550) for Low-Power and Lossy Networks (LLNs) in IoT?
RPL builds a Destination-Oriented Directed Acyclic Graph (DODAG) to route traffic in wireless sensor networks efficiently.