UNIT – II
IOT POINT TO POINT AND M2M COMMUNICATION TECHNOLOGIES
IOT COMMUNICATION PATTERN
In the Internet of Things (IoT), communication patterns define how devices
interact with each other, gateways, and cloud systems. The choice of pattern
depends on factors like latency, bandwidth, power consumption, and data
consistency needs. Here are the most common IoT communication patterns:
1. Device-to-Device (D2D)
Description: Devices communicate directly without involving a central hub
or cloud.
Protocols: Bluetooth, Zigbee, Z-Wave, Wi-Fi Direct.
Use Cases: Smart home devices (e.g., smart bulbs and motion sensors).
2. Device-to-Gateway (D2G)
Description: Devices send data to a local gateway, which aggregates and
sends it to the cloud.
Protocols: MQTT, CoAP, HTTP over LAN; gateway may use Ethernet, cellular,
or Wi-Fi to reach the cloud.
Use Cases: Industrial IoT, remote monitoring.
3. Device-to-Cloud (D2C)
Description: Devices connect directly to cloud services over the internet.
Protocols: MQTT over TCP, HTTP/HTTPS, WebSockets.
Use Cases: Consumer IoT devices like fitness trackers, smart thermostats.
4. Gateway-to-Cloud (G2C)
Description: Gateways handle all device communication and forward
processed or raw data to the cloud.
Protocols: MQTT, AMQP, HTTP, REST APIs.
Use Cases: Environments with intermittent internet connectivity.
5. Cloud-to-Cloud (C2C)
Description: IoT platforms or services exchange data between clouds.
Protocols: REST APIs, Webhooks, gRPC.
Use Cases: Integrating multiple vendor ecosystems (e.g., Alexa and
SmartThings).
6. Device-to-Edge (D2E)
Description: Data is processed locally on an edge device before going to the
cloud.
Protocols: Same as D2G, but with more computing on the edge.
Use Cases: Real-time analytics, video processing, predictive maintenance.
IOT PROTOCOL ARCHITECTURE
The IoT Protocol Architecture refers to the layered structure of communication
protocols that enable the functioning of Internet of Things (IoT) systems. It
provides a standardized way for devices to connect, exchange data, and perform
actions over the internet or private networks.
Here’s a simplified overview of the typical IoT Protocol Architecture, mapped
loosely to the traditional OSI model:
1. Perception Layer (Physical & Data Link Layers – OSI Layers 1-2)
Function: Sensing and data collection from the environment
Technologies/Protocols:
RFID, NFC, Zigbee, Bluetooth, LoRaWAN
IEEE 802.15.4, IEEE 802.11 (Wi-Fi), Ethernet
Modbus, CAN (Controller Area Network)
2. Network Layer (OSI Layer 3)
Function: Routing and transmitting data to other networked devices
Protocols:
IP (IPv4/IPv6) – Base internet protocol
6LoWPAN – IPv6 over Low Power Wireless Personal Area Networks
RPL (Routing Protocol for Low-Power and Lossy Networks)
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3. Transport Layer (OSI Layer 4)
Function: Ensures reliable data transmission
Protocols:
TCP (Transmission Control Protocol) – Reliable connection
UDP (User Datagram Protocol) – Lightweight, faster
DTLS (Datagram Transport Layer Security) – Secures UDP
4. Application Layer (OSI Layers 5-7)
Function: Provides services and interface for user-level interactions
Protocols:
MQTT (Message Queuing Telemetry Transport) – Lightweight pub/sub
CoAP (Constrained Application Protocol) – RESTful, runs over UDP
AMQP, XMPP, DDS – Messaging protocols
HTTP/HTTPS – Web communication
WebSockets – Real-time bidirectional communication
SELECTION OF WIRELESS TECHNOLOGIES
Selecting a wireless technology for an Internet of Things (IoT) application depends
on several factors such as range, power consumption, data rate, cost, scalability,
and latency. Below is an overview of the most common wireless technologies
used in IoT, categorized by typical use cases:
1. Bluetooth / Bluetooth Low Energy (BLE)
Range: Up to 100 meters (BLE ~50m)
Power Consumption: Low
Data Rate: Up to 2 Mbps (BLE)
Use Cases: Wearables, fitness trackers, health monitors, smart home
devices
2. Wi-Fi
Range: 50–100 meters
Power Consumption: High
Data Rate: High (up to several hundred Mbps)
Use Cases: Smart home, surveillance, high-data applications like video
3. Zigbee
Range: 10–100 meters (mesh networking)
Power Consumption: Very low
Data Rate: 250 kbps
Use Cases: Home automation, industrial IoT, smart lighting
4. Z-Wave
Range: ~30–100 meters
Power Consumption: Low
Data Rate: 100 kbps
Use Cases: Smart home systems (especially in the US)
5. LoRa / LoRaWAN
Range: Up to 15+ km (rural), 2–5 km (urban)
Power Consumption: Very low
Data Rate: < 50 kbps
Use Cases: Smart agriculture, asset tracking, environmental monitoring
6. NB-IoT (Narrowband IoT)
Range: Several kilometers (cellular)
Power Consumption: Very low
Data Rate: ~250 kbps
Use Cases: Smart meters, infrastructure monitoring, smart parking
7. Sigfox
Range: Up to 50 km (rural), 3–10 km (urban)
Power Consumption: Very low
Data Rate: ~100 bps
Use Cases: Asset tracking, low-frequency messaging
8. LTE-M (Cat-M1)
Range: Cellular
Power Consumption: Low to medium
Data Rate: 375 kbps to 1 Mbps
Use Cases: Mobile IoT applications, wearables, fleet tracking
9. 5G (Massive IoT Mode)
Range: Depends on frequency (up to several km)
Power Consumption: Medium to high (improving)
Data Rate: Very high
Use Cases: Real-time IoT (e.g., autonomous vehicles, industrial automation)
