物联网介绍

1. 物联网概览与结构(物联网的进化史,拓扑结构,应用领域,通信技术,云与设备关系等等话题) 2. 物联网协议(探讨现有物联网协议的优势与问题,比较常用协议栈诸如MQTT/CoAP等等的异同)
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1.Internet of Things: An Introduction • IoT Overview and Architecture • IoT Communication Protocols • Acknowledgements Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.1

2.What is IoT? Internet of Things (IoT) comprises things that have unique identities and are connected to the Internet The focus on IoT is in the configuration, control and networking via the Internet of devices or “Things” that are traditionally not associated with the internet Eg: pump, utility meter, car engine IoT is a new revolution in the capabilities of the endpoints that are connected to the internet Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.2

3.IoT Evolution Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.3

4.M2M vs IoT Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.4

5.IoT: People Connecting with Things ECG sensor Internet Motion sensor Motion sensor Motion sensor Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.5

6.IoT: Things Connecting with Things - Complex and heterogeneous resources and networks Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.6

7.IoT: Application Areas Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.7

8.IoT Architecture Integrated Application Smart Grid Green Smart TransportEnv. Building Monitor Information Processing Data Center Search Smart Info. Security Data Mining Engine Decision WWAN WMAN Network Construction Internet WPAN WLAN Sensing & Identification GPS Smart RFID Sensor Sensor Device Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.8

9.IoT: Sensors and Actuators Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.9

10.IoT: Sensors Available in the Market (examples) Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.10

11.IoT: Smart Objects (examples) Beaglebone black Intel Galileo Arduino Uno Raspberry Pi Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.11

12.IoT Communication Technologies Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.12

13. IoT Network Topology Unified & Horizontal IoT Platform Device Management/Cloud 3GPP Unlicensed LPWA Licensed 2G/3G/LTE/WiFi/Fixed Networks in ISM LPWA bands (+ other Network(s) bands) NB-IoT + EC-GSM +20dB Link budget Concentrator gain RF Mesh Smart Meters Smart Meter Smart Building Fleet Management Smart Waste Smart Parking with Management Management with battery-powered battery-powered sensors sensors 1.13

14.IoT Cloud: Sensing-As-A-Service Model Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.14

15.IoT Protocols CoAP ( Constrained Application Protocol) MQTT (Message Queue Telemetry Transport) XMPP (Extensible Messaging and Presence Protocol) 6LoWPAN (Low power Wireless Personal Area Networks) Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.15

16.IoT Protocol Architectures Connectivity Power Management Security Rapid Evolution Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.16

17.IoT Protocol Stack Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.17

18.The 6LoWPAN Format • 6LoWPAN is an adaptation header format • Enables the use of IPv6 over low-power wireless links • IPv6 header compression • UDP header compression • Format initially defined in RFC 4944 • Updated by RFC 6282 6LoWPAN: The Wireless Embedded v6.12.2009 Internet, Shelby & Bormann 1.18

19.IoT Transport Layer for Smart Objects • TCP for Smart Objects • UDP for Smart Objects • Advantages • Advantages • Built-in reliability • Low overhead for header size and protocol logic • Mechanism to recover • Less energy for packet lost packets transmission and reception • Control of the maximum size • More space for application of its packets data • Use of the TCP MSS • Small code footprint (Maximum Segment • Well suited for traffic with low Size) option reliability demand. • Drawbacks • Drawbacks • No provision of recovery mechanism for lost packets • Many TCP mechanisms e.g., (application has to recover sliding-window, congestion them) avoidance are not needed in • No mechanism for splitting smart object networks application data into appropriate • Large header size introduces packet sizes. a significant overhead. • Usually, smart object networks deal w/ small packet sizes. Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.19

20.Constrained Application Protocol (CoAP) • IoT oriented and less complex alternative to HTTP • Open IETF standard (RFC 7252) • Datagram Transport Layer Security (DTLS) • Easy proxy to/from HTTP • URIs supported (e.g., coap://hostname:port/leds/red?q=state&on) • RESTfull client-server model • Implements reliable unicast over UDP • Supports best effort multicast • Client-Server & Publish-Subscribe models. Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.20

21.CoAP and HTTP Interworking Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.21

22.CoAP Message Layer Model • Confirmed and non-confirmed message exchange models Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.22

23.CoAP Request/Response Layer Model • Piggy-backed Confirmed • Separate Confirmed Response Response Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.23

24.CoAP Request/Response Layer Model • Non-confirmed Response Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.24

25.CoAP Message Format CoAP message header Description It is 2 bit unsigned integer. It mentions CoAP version Ver number. Set to one. It is 2 bit unsigned integer. Indicates message type viz. T confirmable (0), non-confirmable (1), ACK (2) or RESET(3). It is 4 bit unsigned integer, Indicates length of token (0 to TKL 8 bytes). It is 8 bit unsigned integer, It is split into two parts viz. 3 Code bit class (MSBs) and 5 bit detail (LSBs). 16 bit unsigned integer. Used for matching responses. Message ID Used to detect message duplication. Zero or more option fields may follow a token. A few Options options are Content Format, Accept, Max-Age, Etag, Uri- Path, Uri-Query, etc. Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.25

26.Message Queuing Telemetry Transport (MQTT) • Lightweight messaging protocol designed for sensors and devices with • Flaky network connectivity • Low computing power • Connections where bandwidth is at a premium • Works on top of TCP • Transport Layer Security (TLS) • Protocol specification is open source • Applications: • A way to obtain real world data • Information is gathered by an increasing number of sensors and devices deployed all over • A way to provide real time information • E.g. Locate an item in a supply chain • Accurate current load of a any system (e.g. electricity meters) • Current status of a system (level of liquid in a container, temperature, pressure etc.) • A way to connect all the devices and sensors directly to your messaging infrastructure Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.26

27.MQTT Features • Client/Server model with Clients and Brokers • Publish and subscribe to topics • Managed by the broker • 3 qualities of service • 0 Best effort to deliver a message • 1 Deliver at least once • 2 Deliver exactly once • Supports persistent messages (only most recent per topic) • Minimal transport overhead to reduce network traffic • As little as 2 bytes • Last Will and Testament • MQTT clients can register a custom “last will and testament” message to be sent by the broker if they disconnect. • These messages can be used to signal to subscribers when a device disconnects. Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.27

28.MQTT Architecture • All three clients open TCP connections • At a later time, Client A publishes a value with the broker. Clients B and C subscribe of 22.5 for topic temperature. The broker to the topic temperature . forwards the message to all subscribed clients. Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.28

29.MQTT Topics and Topic Matching • In MQTT, topics are hierarchical, like a filing system (e.g., kitchen/oven/temperature). • Wildcards are allowed when registering a subscription (but not when publishing) allowing whole hierarchies to be observed by clients. • The wildcard + matches any single directory name, # matches any number of directories of any name. • Examples: • kitchen/+/temperature matches kitchen/foo/temperature but not kitchen/foo/bar/temperature • kitchen/# matches kitchen/fridge/compressor/valve1/temperature Prof. António grilo https://fenix.Tecnico.Ulisboa.Pt/homepage/ist14017 RMSF - 2018 1.29