IOT Protocols
- 1. IOT Protocols: MAC, Networking & Session Layer Nagesh T Rao
- 2. Internet of Things - IoT • The Internet of Things (IoT) is the network of physical objects that contain embedded technology to communicate and sense or interact with their internal states or the external environment • Network of Physical Objects • Contains embedded technology • To communicate • Sense • Interact • w/t their internal states or … • The external environment Courtesy: Gartner
- 3. TCP/IP : Quick Revisit Physical Device PPP, SLIP, Ethernet IP, ARP, ICMP TCP, UDP Socket API, Telnet, FTP,TFTP,DHCP,SNMP,HTTP 1. Physical Layer 2. Data Link Layer 3. Network Layer 4. Transport Layer 5-6-7. Application Layer Ethernet Header IP Header TCP Header Application Data Ethernet Trailer Ethernet Frame: Src & Dest. Mac Address IP Header TCP Header Application Data TCP Header Application Data App Header User Data User Data IP Datagram: Src & Dest. IP Address TCP Segment: H2H Comm.
- 4. OSI, TCP/IP, IOT OSI Model TCP/IP Model Layer Functions Protocols Application Layer Application Interact and support user application Http, Https, CoAPP, MQTT, AMQP, SMQP Presentation Layer Session Layer Transport Layer Transport Handle Reliability, Flow Control, Congestion Avoidance, Error Correction TCP, UDP Network Layer Internet Logical Addressing, Routing, SAR IP, 6LoPAN, 6Lo, 6TiSCH, LOADng, RPL, CoRPL, CARP Data Link Layer Network Access and Physical Layer Define physical connection of end devices to the network – Wired or Wireless LPWAN, Wi-Fi, LTE,HART, 802.15.4, BT/ BLE, ZigBee, Z-Wave Physical Layer
- 5. IoT Protocol & Layers • IoT protocols operate at different layers of the networking stack … including: • Medium Access Control (MAC) layer • network layer • session layer MAC • WiFi, BLE, Z-Wave, ZigBeeSmart • DECT/ULE, 3G/LTE, NFC, Weightless, HomePlug GP, 802.11ah, 802.15.4e, G.9959, Wireless HART, DASH7, ANT+, LTE-A, LoRaWAN Network Layer • Routing Protocol • RPL • LOADng • CARP • Encapsulation – 6LoPAN, 6Lo, 6TiSCH Session Layer • MQTT • CoAP • AMQP • SMQTT Protocols offered by Internet Engineering Task Force (IETF), Institute of Electrical and Electronics Engineers (IEEE), International Telecommunication Union (ITU) and other standard organizations.
- 6. Data Link and MAC Protocol IEEE 802.15.4 WiFi Bluetooth Low Energy - BLE ZigBee Z-Wave 3G/LTE 802.11AH LoRaWAN WirlessHART RFID ISA 100.11 NFC • Includes physical (PHY) and MAC layer protocols which are combined by most standards
- 7. Communication Technology Technology Frequency Data Rate Range Power Usage Cost 2G/3G Cellular Brand 384 Kbps/10 Mbps Several Km High High Bluetooth/BLE 2.4 GHz 1,2,3 Mbps 1, 10, 100 m Low Low 802.15.4 Sub GHz, 2.4 GHz 40,250 Kbps 10-75 m Low Low LoRa Sub GHz < 50 Kbps 1.5 – 4.5 Km Low Medium LTE Cellular Brand 1 Gbps Several Km Medium High NB-IoT Cellular Brand 0.1 – 1 Mbps Several Km Medium High SigFox Sub GHz < 1 Kbps Several Km Low Medium Weightless Sub GHz 0.1 – 1 Mbps Several Km Low Low WiFi Sub GHz, 2.4 GHz, 5 GHz 0.1 – 54 Mbps < 100 m Medium Low WirelessHART 2.4 GHz 250 Kbps ~100 m Medium Medium Zigbee 2.4 GHz 250 Kbps ~100 m Low Medium Z-Wave Sub GHz 40 Kbps ~30 m Low Medium 5G 30 GHz 10 Gbps 400 m High High
- 8. IEEE 802.15.4 / 802.15.4e Low Rate Wireless Personal Area Network • IEEE 802.15.4 is the most commonly used MAC Protocol for IoT • Many other popular IoT protocol uses this protocol for their MAC layer – ZigBee, ISA 100.11, Wireless HART etc • It defines frame format, headers with source and destination addresses, and communication between nodes • Traditional networks are not suitable for low power multi-hop networking in IoT due to their large frame formats • IEEE802.15.4e was developed for IoT extending IEEE802.15.4 to support low power communication • Uses time synchronization and channel hopping for high reliability • IEEE 802.15.4e uses slotted frame Structure and is designed for scheduling and telling each node what to do • A node can be in sleep more, or send, or receive information • In the sleep mode, the node switch off its radio to save power and store all messages to send at the next transmission opportunity • When transmitting, it sends its data, wait for acknowledgment and goes to sleep • When receiving, the node turns on its radio before scheduled time to receive, receives the data, sends an acknowledgement, turn off its radio, delivers the data to upper layers and goes to sleep
- 9. 802.11 AH • Also called Wi-Fi HaLow. Developed for low power communication • Uses 900 MHz, compared to traditional Wi-Fi networks which uses 2.4 GHz and 5 GHz bands • Lighter and low overhead version of original IEEE 802.11 Wi-Fi protocol, fitting IOT requirements • Low frame overheads and power consumption • MAC frame is 12 bytes Vs 30 bytes for 802.11 • Low energy consumption, fit for sensors nodes in wireless sensor network (WSN) that can cooperate with other nodes • Competes with Bluetooth, due to its low power requirement, with added benefit of higher data rates and wider coverage area/range
- 10. Zigbee • Zigbee is wireless technology developed as an open global standard to address the unique needs of low-cost, low-power wireless IoT networks. • The Zigbee standard operates on the IEEE 802.15.4 physical radio specification • It works in unlicensed bands including 2.4 GHz, 900 MHz and 868 MHz • ZigBee is used for a large range of IoT applications including but not limited to smart homes, healthcare systems and remote controls. • The ZigBee protocol is determined by layer 3 and above. For the PHY and MAC it is defined by 802.15.4 layers 1 and 2 • Supports wide range of network topologies including star, peer-to- peer and mesh. • Zigbee based sensor nodes are very popular in WSN when implemented in Mesh topology. • The network is controlled by the co-ordinator and is the central node in a star topology or, root in a tree or, be located anywhere in mesh topology • ZigBee device can be of following types • ZigBee Coordinator, ZigBee Router(ZR), ZigBee end-device (ZED)
- 11. Bluetooth & Bluetooth Low Energy (BLE) • Bluetooth is a short range communication technology. • IEEE 802.15.1 has adopted the standard for Physical and MAC layer based on Bluetooth technology spec 1.1 • Developed for replacing cables connecting portable units • Its is based on Ad-hoc technology also known as ad-hoc Piconet • It follows master/slave architecture and offers two types of frames: advertising & data frames • The Advertising frame is for discovery and is sent by slaves on one or more dedicated advertisement channels • Master nodes sense advertisement channels to find slaves and connect with them • After connection is established, the master tells the slave it’s waking cycle and scheduling sequence • Nodes are awake only during communication, otherwise they go to sleep to save the power • Bluetooth low energy (BLE) is developed for low data rate, better power saving and supporting massive number of slaves helping IoT based applications • BLE’s power consumption is nearly half that of classic Bluetooth device • BLE supports 24 bit address vs classic Bluetooth 3 bit. Theoretically almost unlimited slaves (224 – 1) ! • Topology can be point-to-point, point-to- multipoint, start & mesh • BLE range is more than that of Bluetooth. Can support range up to 400 m as per BLE 5.0 • Use case include – medical device – BP monitor, Activity Tracker, audio HS • Can be used even for developing IoT gateway
- 12. Z-wave • Zwave (or Z‐wave) is a protocol developed for communication among devices typically for home automation • It has communication range of ~100 feet point-to-point and is suitable for small messages in IoT applications, smart homes, wearable healthcare, remote control and others. • It uses CSMA/CA for collision detection and ACK messages for reliable transmission • Follows Master/Slave config. • A Master sets‐up and manages a Zwave network • Each logical Zwave network has 1 Home (Network) ID and multiple node IDs - upto 232 nodes • Nodes related to one network (home id) can not communicate with other network (different home id) • Devices communicate with one another when in range • When devices are not in range, messages are routed though different nodes to bypass obstructions or radio dead spot • This is called Healing
- 13. HART/Wireless HART • HART - Highway Addressable Remote Transducer – developed for supporting large number of field devices for field networks • It is a bidirectional request-response communication protocol • Uses current loop technology, supporting analog and digital sensors • Wireless version of HART makes it more cost efficient and easier to implement • The Wired HART differs from the Wireless version where the wired version lacks Network Layer. Both have different physical and data link layer • Application layer is common for both Wired and Wireless • The physical layer of the wireless HART is based on 802.15.4 • Operated only in 2.4 GHz of the ISM band • It uses 15 channels to support reliability, uses super-frames, channel hopping and channel blacklisting for transmission quality • Uses Mesh topology where each device is prepared to forward packets from every other devices and have updated network graph to handle routing • The network manager supervises each node and decides who will send the packet and who listen and frequency for each time slot • It also handles security by deciding which node can join the network preventing unauthorized node from joining
- 14. ISA 100.11A • Developed by International Society of Automation for large scale industrial plant automation • This is one more protocol based on 802.15.4 • Network and Transport layer is based on IP and TCP / UDP with IPv6 support for 802.15.4 i.e 6LoPAN • Topology support includes Mesh, Star and Tree • Can also be integrated with wired networks using ethernet – ISA over Ethernet • To address interference issues over wireless channels in the same band, it uses frequency hopping spread spectrum (FHSS) over a total of 16 channels. • Channel blacklisting is also used to further improved the quality • Support tunnelling mode to allow legacy data through the ISA100.11A network • 128 bit AES to secure all communication. Data link layer secures the frames with each hopping and Transport layer secures the pear-to-pear communication
- 15. CAN – Controller Area Network / CAN Bus • CAN enables fast communication between electronic devices and modules in vehicles • It is a robust in-vehicle bus standard designed, supporting message based communication • It is a multi-master serial bus standard for connecting Electronic Control Units (ECUs) • Allows microcontrollers and devices to communicate with each other's applications without a host computer • In case if more than one device try to transmit at the same time the highest priority device is gets the chance to continue while the other devises are put on hold • ISO 11898-1 and ISO 11898-2 • It is a broadcast type bus • 1 Mbit/second. Max cable 40m • 120 Ohms cable
- 16. LPWAN – Low Power Wide Area Network LoRaWAN LoRa SigFox Symphony Link Weightless LTE-M NB-IoT
- 17. LoRa • LoRa and LoRaWAN are different • LoRaWAN is a protocol for WAN communications and • LoRa is a technology for wide area network. • LoRa is a non-cellular modulation technology for LoRaWAN • LoRa is used primarily in two ways: • One is LoRaWAN, predominantly deployed in Europe. It has very small message capacity – 12 bytes. • Another is Symphony Link, which is a product of Link Labs. • Symphony Link is a preoperatory wireless system owned by Semtech, built on LoRa technology that is designed to overcome the limitations of a LoRaWAN systems • Symphony Link is often included as a component of more complex LoRa networking solutions, used mostly in the U.S. and Canada, and is designed for industrial applications • LoRa is a radio network technology used for IoT solutions and has better link budgets than other comparable radio technologies. • However apart from some key European markets, if one want to connect to LoRaWAN networks—or use LoRa at all—one needs to deploy their own network gateway
- 18. NB-IoT Narrow Band IoT • NB-IoT is a 3GPP initiative • Addresses the IoT needs of very low data rate devices that can connect to mobile networks, may often be powered by batteries • It is a cellular standard for IoT devices to be interoperable and more reliable • Uses OFDM modulation • The chips are complex, but the link budgets are better • Users get the high performance level associated with cellular connections, at the cost of more complexity and greater power consumption • NB-IoT can be used to send and receive small amounts of data—a few tens or hundreds of bytes per day produced by low data-generating IoT nodes/devices • It supports message-based communication with faster modulation rate that can handle a lot more data than other low power communication technologies • It is non IP-based communication protocol • It was developed for simple IoT applications and is much more power efficient than LTE-M but designed for more infrequent communication
- 19. LTE-M • LTE-M - Machine Type Communication, which includes eMTC enhanced Machine Type Communication is a type of low power wide area network (LPWAN) radio technology standard from 3GPP • IP based communication • Higher data rate in comparison to NB-IoT • Supports Mobility and Voice over the network • But it requires higher bandwidth • Due to its complexity it is less economical
- 20. SigFox • SigFox is a proprietary Low Power WAN network • It has the lowest cost radio modules • Sigfox is uplink only. • Downlink is possible, but highly limited by bandwidth, their link budget is not supported to downlink • Sigfox is an end-to-end network and technology company • Advantage • It consumes a low amount of power • Works well for low power devices that transmit infrequently • It sends very small amounts of data at a very low rate • It supports wide coverage in the areas the network is implemented • Disadvantage • Network is deployed only in some geography • Communication is better from the IoT node to endpoint to the base station. • Though it has bidirectional functionality, but its has constrain to communicate from the base station back to the endpoint • Poor link budget for downlink than going up • Mobility will be a problem with Sigfox device
- 21. RFID – Radio Frequency Identification • RFID is a technology whereby digital data encoded in RFID tags or smart labels are captured by a RFID reader using radio waves RFID is similar to barcoding in that data from a tag or label are captured by a device that stores the data in a database. RFID, however, has several advantages over systems that use barcode asset tracking software. The most notable is that RFID tag data can be read outside the line- of-sight, whereas barcodes must be aligned with an optical scanner. RFID systems consist of three components: • an RFID tag or smart label • an RFID reader and … • An antenna. • RFID tags contain an integrated circuit and an antenna, which are used to transmit data to the RFID reader (also called an interrogator). • The reader then converts the radio waves to a more usable form of data. • Information collected from the tags is then transferred through a communications interface to a host computer system, where the data can be stored in a database and analysed at a later time. • Active Tags Vs Passive Tags • Passive tags must be “powered up” by the RFID reader before they can transmit data Source : AB&R®
- 22. Network Layer : Routing Protocols • Standard and non-standard protocols for routing • Routing in network layer handles the packet transfer from source to destination for IoT applications •Distance Vector IPv6 based routing protocol for low power lossy networks •Builds a Destination Oriented Directed Acyclic Graph (DODAG) which can have only one route from leaf node to the root • Low rate beaconing used for maintain topology • Routing info in datagram packet itself RPL • Routing base on AODV, extended for use in IoT • Generation of Route Requests by the originator i.e LOADng router for path discovery to the destination • Intermediate nodes receives the route request and forwards the request to the next node until the request reaches the destination LOADng router • Destination router generates the route reply and the route is established LOADng •Channel-Aware Routing Protocol (CARP) is designed for underwater communication and used in IoT •It is a distributed routing protocol and uses lightweight packets •Uses link quality as a parameter to establish the route, which is computed based on successful historical transmission. This quality parameter is gathered from neighbouring sensors, based on which it selects the forwarding nodes. CARP
- 23. Network Layer : Encapsulation Protocols • Problem with IoT applications is that IPv6 addresses are too long and cannot fit in most IoT datalink frames which are relatively smaller • IETF has developed a set of standards to encapsulate IPv6 datagrams in different datalink layer frames for use in IoT applications •Low power Wireless Personal Area Network over IPv6 •Allows low power resource constrained devices to connect to Internet •Most common standard for Ipv6 encapsulation •Allows 802.15.4 radio to carry 128 bit address of IPv6. This is active through header compression, translation and reformatting •IETF RFC 5933 and RFC 4919 6LoPAN •6TiSCH is developed by a different group in IETF, for Time-Slotted Channel Hopping (TiSCH) mode of IEEE 802.15.4e datalinks 6TiSCH • This again is a group in IETF to address fitting the IPv6 into data links other than what is addressed by 6LoPAN and 6TiSCH 6LO
- 24. Session Layer Protocols MQTT SMQTT AMQP XMPP DDS
- 25. MQTT • A lightweight text based messaging protocol based on publish-subscribe architecture • Uses TCP/IP • Provides message based communication between application & middleware on one side, and network and communication on other side • The system consists of three main components: • Publishers • Subscribers, and • Broker • Publishers are lightweight sensors that connect to the broker to transmit their data and go back to sleep • Subscribers are applications that are interested in the sensory data based on topic, it subscribes to the broker to be informed whenever relevant data is received • The brokers classify sensory data into topics and send them to subscribers who has subscribed to the topics • A Topic is a simple string that can have hierarchies and wild cards separated by a “/” • A topic can look like the following … • home/kitchen/temperature OR • home/+/temperature (sends the temperature of all areas of home
- 26. SMQTT – Secure MQTT • SMQTT is the secured version of the MQTT which uses encryption based on lightweight attribute • The main advantage of using such encryption is the broadcast encryption feature, in which the message is encrypted and delivered to multiple other nodes • Algorithm consists of four main stages: • Setup • Encryption • Publish • decryption • In the setup phase, the subscribers and publishers register themselves to the broker and get a master secret key according to their developer’s choice of key generation algorithm • When the data is published, it is encrypted, published by the broker and sends it to the subscribers who finally decrypts. The subscriber should be having the same master secret key for successful decryption • It is to be noted that the key generation and encryption algorithms are not standardized
- 27. AMQP – Advance Message Queuing Protocol • AMQP is a session layer protocol • It is designed to connect between systems and business processes supporting inter organization communication • It uses a publish/ subscribe architecture implemented using TCP • Basic unit of data is frames • Here the broker is divided into two main components: • exchange • queues • The exchange receives the messages from publisher (IoT nodes) and distributing them to queues based on pre-defined roles and conditions. • Queues represent the topics and subscribed by subscribers which will get the sensory data whenever they are available in the queue • RabbitMQ uses AMQP
- 28. CoAP - Constrained Application Protocol • CoAP is a session layer protocol which provides lightweight RESTful (HTTP) interface • Representational State Transfer (REST) is a standard interface between HTTP client and servers • REST could result in significant overhead and power consumption making it unsuitable for use in IoT • CoAP is designed for IoT and enables low- power sensors to use RESTful services while meeting their low power requirement • It is built over UDP, instead of TCP and has a mechanism to provide reliability • CoAP architecture has two sublayers: • messaging • request/response • The messaging sublayer is responsible for reliability of the communication and ensure no duplication of messages • Request/response sublayer is responsible for communication
- 29. Comparison of Session Protocols Protocol UDP/TCP Architecture Security & QoS Header Size Max Length (Bytes) MQTT TCP Pub/Subscriber Both 2 5 AMQP TCP Pub/Subscriber Both 8 - CoAPP UDP Req/Response Both 4 20 (typical) XMPP TCP Both Security - - DDS TCP/UDP Pub/Subscriber QoS - -
- 30. Thank You Nagesh T. Rao nagesh_t_rao@hotmail.com