Question

Provide a comparison of at least 10 Internet of Things communication protocols. Provide your answer in a table format labelling each comparison parameter with a suitable heading. Use at least 5 parameters for comparison.

Answer 1

I would like to give you the basic idea of Communication protocols in IOT before starting the Comparison and i am assuming you to have the basic knowledge of the protocols as well:

This table shows us the different protocols present and the metrics used for them with Results as well as these metrics and Protocols. Please try to understand this table as this will be making the base you need to further understand the protocol. To start with let's see some basics:

MQTT, AMQP, XMPP, and REST HTTP, are designed to run on networks that use TCP, while CoAP uses UDP as the underlying transport. DDS primarily uses UDP as its underlying transport, but it also supports TCP. As mentioned in the previous section, MQTT, AMQP, and DDS implement a publish/subscribe model, while REST HTTP and CoAP implement a request/reply interaction model. MQTT, AMQP, and CoAP protocols provide very basic QoS support for delivering messages. MQTT and AMQP implement three different QoS levels, while in CoAP request and reply messages are limited to two. The QoS in REST HTTP and XMPP are provided by the underlying transport protocols. DDS, on the other hand, provides a rich set of QoS policies with over 20 different QoS options defined by the standard. Most of these protocols choose TLS or DTLS protocol as security mechanisms. Readers interested more in applications of these protocols in various segments (IoT, fog, and cloud) and less so in the protocols design itself, or readers familiar with individual protocols can skip this section or parts of it.

Protocols	Latency	Bandwidth consumption and throughput	Energy consumption	Security	Open challenges and efforts in constrained environments
HTTP	Longer compared to MQTT.	For high throughput and bandwidth, REST HTTP is recommended.	HTTP was much larger in terms of consumption when compared to MQTT.	Lower than AMQP but higher than CoAP	TLS version 1.3; HTTP/2.0 version
Constrained Application Protocol (CoAP)	Takes more time compared to MQTT.	Where message size was small, and independently of the increase of packet loss rate, CoAP consumed less bandwidth than MQTT	CoAP is most efficient in terms of energy consumption.	Higher than MQTT but lower than HTTP	TLS version 1.3; MQTT-SN (based on UDP)
Message Queue Telemetry Transport Protocol (MQTT)	Shorter compared to HTTP.	Lower efficiency when compared to COAP.	HTTP was much larger than with MQTT	Low	DTLS optimization
Data Distribution Service (DDS)	DDS outperforms MQTT in terms of experienced telemetry latency.	DDS is not so efficient, for the sake of understanding, DDS consumed approximately twice the bandwidth of MQTT.	---------		not recommended for constrained devices
Advanced Message Queueing Protocol (AMQP)	Almost the same when compared to MQTT for small payloads but slower when payloads are high.	The throughput and bandwidth are both average criteria for it.	AMQP was found out to be slower than MQTT.	High	DDS security specification
Extensible Messaging and Presence Protocol (XMPP)	Average latency when compared to all.	Same as AMQP.	Low energy is required.	It has TCP protocol based on XML-Stanzas and this provides more reliable and secure communication.	light-weight XMPP publish-subscribe scheme

Summary of comparison on the basis of Latency: The shortest latency was produced by the MQTT protocol, followed by AMQP, while the difference between XMPP and DDS was negligible compared MQTT, CoAP, HTTP and AMQP messaging protocols based on their average latency among other parameters. The results have shown the highest latency in HTTP, followed by AMQP and MQTT respectively, with CoAP having the lowest latency results.

Proper comparasion with key point are showed in the table given below:

And this being the proper timeline and some proper down the line facts to be kept in mind :