nptel 2, introduction to iot, By Prof. Sudip Misra

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Introduction to IoT – Part II
Dr. Sudip Misra
Associate Professor
Department of Computer Science and Engineering
IIT KHARAGPUR
Email: smisra@sit.iitkgp.ernet.in
Website: http://cse.iitkgp.ac.in/~smisra/
Introduction to Internet of Things

IoT Resulting in Address Crunch
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 Estimated 20-50 billion devices by 2018
 Reason is the integration of existing devices, smart devices as well as constrained
nodes in a singular framework.
 Integration of various connectivity features such as cellular, Wi-Fi, ethernet with
upcoming ones such as Bluetooth Low Energy (BLE), DASH7, Insteon, IEEE 802.15.4,
etc.
 The ITU vision is approaching reality as the present day networked devices have
outnumbered humans on earth.
Reference:
 Cisco Systems, (2011). The Internet of Things How the Next Evolution of the Internet Is Changing Everything [Online]. Available:
http://www.cisco.com/web/about/ac79/docs/innov/IoT_IBSG_0411FINAL.pdf
 ITU Broadband Commission, (2012). The State of Broadband 2012: Achieving Digital Inclusion for All ITU Broadband Commission Report, [Online]. Available:
http://www.broadbandcommission.org/ Documents/bbannualreport2012.pdf
 Ericsson, (2011). More than 50 Billion Connected Devices, [Online]. Available: http://www.ericsson.com/res/docs/whitepapers/wp-50billions.pdf

Connectivity Terminologies
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•Local, Short range Comm, May or may not connect to Internet, Building or Organization
wide
IoT LAN
•Connection of various network segments, Organizationally and geographically wide, Connects to
the internet
IoT WAN
•Connected to other nodes inside a LAN via the IoT LAN, May be sometimes connected to the
internet through a WAN directly
IoT Node
•A router connecting the IoT LAN to a WAN to the Internet, Can implement several LAN
and WAN, Forwards packets between LAN and WAN on the IP layer
IoT Gateway
•Performs active application layer functions between IoT nodes and other entities
IoT Proxy

IoT Network Configurations
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Node
Source: Teemu Savolainen, Jonne Soininen, and Bilhanan Silverajan,”IPv6 Addressing Strategies for IoT”, IEEE Sensors Journal, Vol. 13, No. 10,
Oct 2013

 Some of the IoT network configurations restricted to local areas,
analogous to normal LANs, WANs and proxy are shown in the
previous figures.
 The nodes represented by green circles have L: local link addresses
or LU: local link addresses which are unique locally.
 Nodes within a gateway’s jurisdiction have addresses that are valid
within the gateway’s domain only.
 The same addresses may be repeated in the domain of another
gateway. The gateway has a unique network prefix, which can be
used to identify them globally.
 This strategy saves a lot of unnecessary address wastage. Although,
the nodes have to communicate to the internet via the gateway.
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Gateway Prefix Allotment
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 One of the strategies of address conservation in IoT
is to use local addresses which exist uniquely within
the domain of the gateway. These are represented
by the circles in this slide.
 The network connected to the internet has routers
with their set of addresses and ranges.
 These routers have multiple gateways connected to
them which can forward packets from the nodes, to
the Internet, only via these routers. These routers
assign prefixes to gateways under them, so that the
gateways can be identified with them.
Oct 2013

Impact of Mobility on Addressing
 The network prefix changes from
1 to 2 due to movement, making
the IoT LAN safe from changes
due to movements.
 IoT gateway WAN address
changes without change in LAN
address. This is achieved using
ULA.
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Oct 2013
Has the
global view
of the
network
underneath

 The gateways assigned with prefixes, which are attached to a
remote anchor point by using various protocols such as Mobile
IPv6, and are immune to changes of network prefixes.
 This is achieved using LU. The address of the nodes within the
gateways remain unchanged as the gateways provide them with
locally unique address and the change in gateway’s network prefix
doesn’t affect them.
 Sometimes, there is a need for the nodes to communicate directly
to the internet. This is achieved by tunneling, where the nodes
communicate to a remote anchor point instead of channeling their
packets through the router which is achieved by using tunneling
protocols such as IKEv2:internet key exchange version 2
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Gateways
 IoT gateways with or without proxies responsible mainly for:
 Internet connectivity
 IoT LAN intra-connectivity
 Upstream address prefixes are obtained using mechanisms like
DHCPv6 and delegated to the nodes using SLAAC (stateless
addressing).
 LU addresses are maintained independently of globally routable
addresses, in cases were internal address stability is of prime
concern.
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Oct 2013

 Despite providing address stability, LUcannot communicate
directly with the internet or the upper layers, which is solved
by implementing an application layer proxy.
 Application layer proxies may be additionally configured to
process data, rather than just passing it.
 In nodes with no support for computationally intensive tasks,
IoT proxy gathers data sent to the link-local multicast address
and routes them globally.
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 Presently, the Internet is mainly IPv4, based with little or no
IPv6 uplink facilities or support.
 Due to the lack of a universal transition solution to IPv6, lots
of un-optimized solutions are being used for IoT deployment.
 These makeshift solutions mainly address:
 IPv6 to IPv4 translation
 IPv6 tunneling over IPv4
 Application layer proxies (e.g: data relaying)
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Multi-homing
 A node/network connected to multiple networks for
improved reliability.
 In cases of small IoT LANs, where allotment of address
prefixes is not feasible and possible, a proxy based approach is
used to manage multiple IP addresses and map them to link
local addresses.
 In another, gateway-based approach is used for assigning link
local addresses to the nodes under it.
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Oct 2013

 Providing source addresses, destination addresses and routing
information to the multi-homed nodes is the real challenge in
multi-homing networks.
 In case the destination and source addresses originate from
the same prefix, routing between gateways can be employed
for IoT gateway selection.
 Presently, IEFT is still trying to standardize this issue.
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IPv4 versus IPv6
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IPv4 IPv6
Developed IETF 1974 IEF 1998
Length (bits) 32 128
No. of Addresses 2^32 2^128
Notation Dotted Decimal Hexadecimal
Dynamic Allocation of
addresses
DHCP SLAAC/ DHCPv6
IPSec Optional Compulsory

IPv4 versus IPv6
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IPv4 IPv6
Header Size Variable Fixed
Header Checksum Yes No
Header Options Yes No
Broadcast Addresses Yes No
Multicast Address No Yes

IPv4 Header Format
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1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
Ver IHL Type of Service Total Length
Identification Flags Fragment Offset
Time to Live Protocol Header Checksum
Source Address (32 bit)
Destination Address (32 bit)
Options Padding

IPv4
 The IPv4 emphasizes more on reliable transmission, as is
evident by fields such as type of service, total length, id,
offset, TTL, checksum fields.
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IPv6 Header Format
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1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
Ver Traffic Class Flow Label
Payload Length Next Header Hop Limit
Source Address (128 bit)
Destination Length (128 bit)

IPv6
 The IPv6 header structure is more simpler as it mainly focuses
on the addressing part of the source and destination.
 It is concerned more with addressing than with reliability of
data delivery.
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