First, according to the network protocol four classification:
NB-IoT, LORA, WIFI, Bluetooth, zigbee, 4G is the physical layer, these all need support chip modules (hardware support)
And MQTT, COAP, HTTP is an application layer protocol, which requires the development server, or docking cloud platform vendors (software support)
Therefore (MQTT, COAP, HTTP) is resident (NB-IoT, LORA, WIFI, Bluetooth, zigbee, 4G) of the upper protocol in the physical layer
Second, as required gateway Category:
Gateway is not required: NB-IoT, 4G (chip can be directly connected on Mobile, China Unicom, telecom operators)
A gateway is needed: LORA, WIFI, zigbee (not directly connected to the telecom operators need to transit through a gateway to connect to the telecom operators)
Bluetooth is rather special, is the interconnection between two Bluetooth devices
Three, NB-IoT, 4G comparison:
NB-IoT low power consumption, small data transmission, the transmission speed at the end, chip modules and packages cheaper
4G: fast transmission speed and can transfer large data, but high power consumption, expensive
And comparative WIFI zigbee:
high power wifi, fast data transmission, a routing device only added less
low-power zigbee, slow data transmission, may relay, a zigbee zigbee gateway device can be added thousands
Fourth, the application layer protocol: MQTT and Comparative COAP
1, MQTT
mqtt is based on a client - server message publish / subscribe transport protocol. MQTT agreement is lightweight, simple, open and easy to implement, these features make it suitable for a very wide range.
In many cases, including constrained environments, such as: machine to machine (M2M) communication, and things (the IoT), a satellite communications link sensor occasional dial medical equipment, intelligent home, and a number of devices have been downsized widely used
2、coap
2.1, COAP network transport layer protocol to a TCP UDP.
2.2, the same address and Internet-based resources REST, server has a similar url format, the client also has POST, GET, PUT, DELETE method to access the server, to make HTTP simplified.
2.3, COAP is a binary format, HTTP is a text format, COAP is more compact than HTTP.
2.4, the weight, the minimum length of the head only COAP 4B, a HTTP are dozens of B
2.5, supports reliable transmission, the data retransmission, block transfer. Ensure reliable data arrives.
2.6, supports IP multicast, which can send a request to a plurality of devices simultaneously.
2.7, no long communication connection, for low power things scene.