Introduction to Internet of Things

1. Introduction to
Internet of Things
Nagasai Panchakarla
opendevicelab.in
July 2013

2. Agenda
● Introduction
● Constraints
● Protocol Stack
● DTN
● Software
● Hardware

4. Internet of Things
● Everything that benefits from networking will eventually be connected
● Interoperability
● Legacy
● Technology is already there
● Universal identity, IPv6
● Endless applications
● Devices+Services
– Data collection, vizualization, smart control...

5. IPv6...Picture credit: iStockphoto/chris_lemmens

6. Kon-Tiki expedition
Expedition across the Pacific Ocean with limited resources (recreations of prehistoric
voyage) in 1947

7. Constraints
● Scalability
● Power source
● Security and Privacy
● Processing powers
● Low bandwidth
● Unreliable links
● Usability
● Business models
● Standardization
● Cost

8. Protocol Stack
Application
Transport
Network
Link
XML
HTTP
TCP
IP
802.11, 802.3 etc
EXI
CoAP
UDP
6LoWPAN
802.15.4
100s-1000s of bytes 10s of bytes
TCP/IP IoT

9. Wireless Technologies
Standard IEEE 802.15.4 Bluetooth Wi-Fi
Frequency 868/915MHz,
2.4 GHz
2.4GHz 2.4, 5.8 GHz
Data rate 250kbps 723 kbps 11 to 105 Mbps
Range 10 to 300 m 10m 10 to 100m
Power Very Low Low High
Battery Operation Alkaline
(months to years)
Rechargeable
(days to weeks)
Rechargeable
(hours)

10. IEEE 802.15.4
● Low power, low data rate wireless standard
● It is not Zigbee
● MAC and PHY layer protocol
● Operates on several bands:
– 2.4 GHz ISM band, 915 Mhz, 868 MHz
● Local regulations
● MTU: 127 Bytes per frame (including headers)
● Data rates upto 250kbps

11. 6LoWPAN
● IPv6 over Low power Wireless Personal Area Networks
● RFC 4944 and RFC 6282
● Adaptation layer
● Header compression
– Stateless or context-based compression
– Compression of addresses
● Neighbor discovery
● IPv6 MTU: 1280 bytes, 802.15.4 MTU: 127 bytes.
– Fragmentation and Reassembly
● IPv6 header overhead: 802.15.4 MAC header upto 25-bytes + 40-byte IP header +
8-byte UDP

12. CoAP
● Constraint Application Protocol
● Accepted as RFC in July 2013
● RESTful web protocol
● GET, POST, PUT, DELETE methods
● Simple Request/Response exchange
● URI (Uniform Resource Identifiers) support
– coap://test.com:<port>/~temperature/sensor1.xml
● Proxy to/from HTTP
● < 10 bytes header
● Simple caching
● Libcoap, contiki, Firefox CoAP plugin

13. EXI
● Efficient XML Interchange
● Standardized by W3C, March 2011
● Compression of XML encoded content
● Compact XML representation
● High processing performace
● OpenEXI,EXIficient

14. Working groups
● 6lowpan (IPv6 over LoWPANs)
– 2007: RFCs 4919 (requirements) and 4944 (6LoWPAN
standard)
– 2011: RFC 6282 as an update for RFC 4944
● Roll (routing over low power and lossy networks)
– 2011: RFC 6206 (Trickle protocol)
– 2012: RFCs 6550 (RPL) and 6552 (Objective Function
Zero)
● Core (constrained RESTful environments)
– 2013: CoAP (draft-ietf-core-coap)

15. DTN
● Delay Tolerant Networks
● Store, carry and forward paradigm
● Hop-by-hop retransmission
● Challenged networks
– Unreachable nodes
– Lack of end-to-end path
– Delays and disruptions
● Saving costs?

16. Operating Systems
● Contiki
– less than 10kB RAM and 30 kB ROM.
– Highly portable, multithreaded, preemptive
– Supports IPv6, 802.15.4, and 6LoWPAN
● Tiny OS
– nesC language, non preemptive, eventdriven,
● Nano-RK
– less than 2kB of RAM and 18kB of ROM
● Mantis, LiteOS, FreeRTOS

17. Hardware platforms
Platforms MCU/SoC Transceiver
TelosB TI MSP430x (10 KB
RAM+48KB flash)
2.4 GHz IEEE
802.15.4
Micaz ATMEGA 128 (4 KB
RAM)
TI CC2420 802.15.4
Redbee Freescale MC1322x
(96 KB RAM + 120
KB flash)
2.4 GHz 802.15.4
Wismote MSP430 (RAM : 16
Kbytes flash : 256
Kbytes)
CC2520
Waspmote Atmel ATmega 1281
(8KB RAM, 128 KB
FLASH ROM, 4 KB
EEPROM, 2 GB SD
card)
ZigBee/802.15.4/Digi
Mesh/RF, 2.4
GHz/868/900 MHz
Arduino
(Various models)
ATmega328 Many
Raspberry Pi Broadcom BCM2835 Any

18. Thanks
"One machine can do the work of fifty ordinary men. No machine can do
the work of one extraordinary man."
- Elbert Hubbard

19. References
● Jari Arkko,Building the Internet of Things
http://www.arkko.com/publications/vitel_arkko.pdf
● G. Montenegro, N. Kushalnagar, J. Hui, D. Culler. Transmission of IPv6 Packets over IEEE 802.15.4
Networks. RFC 4944, IETF, September, 2007
http://tools.ietf.org/html/rfc4944
● IERC - Internet of Things European Research Cluster - 3rd edition of the Cluster Book
http://www.internet-of-things-research.eu/pdf/IERC_Cluster_Book_2012_WEB.pdf
● http://isoc.org/wp/ietfjournal/?p=2066
● https://www.sics.se/search/content/contiki
● Adam Dunkels. Contiki Crash Course
http://www.ee.kth.se/~mikaelj/wsn_course/contiki-course-kth-9oct2008-draft.pdf
● RFC 4838: Delay-Tolerant Networking Architecture
http://tools.ietf.org/html/rfc4838
● Efficient XML Interchange Working Group
http://www.w3.org/XML/EXI/
● http://www.w3.org/TR/exi-evaluation/