The implementation of embedded IPv6 applications in an IPv4 world require one of several strategies of converting or tunneling IPv6 traffic through the IPv4 internet.

2. IoT Hurdles: Designing IPv6
Things in an IPv4 World
Jonny Doin
CEO – GridVortex Systems

3. Agenda
! Introduction
! IPv6
! Mesh Networks
! 6loWPAN: Header Compression and Border Routers
! UDP instead of TCP
! IPv6 => IPv4 Transition Mechanisms
! Example: Android App interfacing with IoT application
– P2P with embedded devices
– Integration with IPv6
! Final Thoughts

4. Introduction
! The Internet will see all kinds of Embedded Devices
and new applications
! While the data traffic of those systems may not be too
large, there must be an unique address for each one
Source: http://www.satiztpm.it/internet-things

5. IPv6
! The new Embedded Applications will add billions to trillions
of new unique addresses to the Internet
! Hard Fact: full depletion of the adress space for the IPv4
(32 bits worth of unique addresses – 4 bytes)
! IPv6: 16 bytes (128 bits) of addressing, or 7.9 * 1028 times
more addresses
! Caveat: IPv6 headers are 4 times longer than IPv4 headers
http://www.digitaltrends.com/computing/world-ipv6-launch-day-explained-the-next-unseen-evolution-of-the-web/#!bG589T

6. IPv6 (2)
! The new expanded address range is much better
than expanding the effective address space of IPv4
using NAT (Network Address Translation)
! Stateless Address Auto Configuration – SLAAC
(RFC4862, RFC4941)
! Neighbor Discovery – ND (RFC4861, RFC6775)

7. IPv6 (3)
! IPv6 headers take 40 bytes, compared to 20 bytes
for IPv4
source: Wikipedia

8. Why IPv6 ?
! IPv6 is a lighter protocol than IPv4
! Lower management overhead, important in
embedded applications
! No need for centralized node address configuration
! IPv4 address space saturation will only get worse
! IPv6 applications are simpler to design and deploy

9. Mesh Networks
Source: Industrial Ethernet Book, issue 49 / 36
! Dynamic Self-Healing algorithms used to promote reorganization of
node interconnections
! Increased network reach at lower power radio
! In Mesh Networks each mesh node takes part in
the packet routing

10. 6loWPAN
! IPv6 over Low Power Wireless Personal Area
Networks
! Unique address for each node in the mesh
! Designed to be implemented on 802.15.4 radio
networks
! Main feature is IPv6 header compression
! Enables Internet connectivity for 802.15.4 networks

11. 6loWPAN: Header Compression
! The standard IPv6 packet MTU is at least 1280
bytes
! 802.15.4 MTU is only 127 bytes
! The standard headers for IPv6 leave a rather small
room for user payload
! The response to that problem is Header
Compression
! Header Compression schemes allow context-
based compression downto 2 bytes of header

12. 6loWPAN: Border Router
! Connects 6loWPAN
meshes to the Internet
! Handles header
compression/expansion
! Gateway between at
least two different
network interfaces
by the edge router for autoconfiguration. The edge router then configures the
01:300a:1::/48 to its IEEE802.15.4 wireless interface. Note that the LoWPAN
link are on different subnets as this uses the Simple LoWPAN model. The
4 wireless devices in the LoWPAN assume a default channel and security
he edge router starts advertising the IPv6 prefix, which is used by the three
orm Stateless Address Autoconfiguration, and to register with the edge router
IPv6 Internet
Remote server
Router
H
H
H
R R
R
LoWPAN
P2P link
2001:300a:1::/48
2001:300a::/32
2001:a03f::1ffa
::1
::2
::3
::4::5
::6
::7
Edge router
Figure 1.13 A 6LoWPAN example.Source: SHELBY, Zach. BORMANN, Carsten. 6LOWPAN The Wireless
Embedded Internet. Chichester, UK: Wiley, 2009

13. 6loWPAN: Border Router (2)
! Example: 6loWPAN /
802.3 gateway
! Enables seamless P2P
connectivity between
loWPAN nodes and
standard UDP/IP
devices
! Direct connection to,
e.g., SmartPhones,
Tablets, Computers and
other 6loWPAN devices
over the Internet
6LoWPAN: THE WIRELESS EMBEDDED INTERNET
6LoWPAN
interface
Ethernet
interface
IPv6
eth0 6lowpan0
6LoWPAN driverEthernet driver
TCP UDP ICMP
gure 6.8 Edge router with a 6LoWPAN network interface.
ral, e.g. in the form of a USB stick. The interface between the wireless
Source: SHELBY, Zach. BORMANN, Carsten. 6LOWPAN The Wireless
Embedded Internet. Chichester, UK: Wiley, 2009

14. 6loWPAN: UDP instead of TCP
! 6loWPAN meshes are low-bandwidth and low-
power networks
! CSMA-CA (collision avoidance): wait for free
channel to talk
! UDP have the smallest utilization of the channels
! TCP is too heavy for these networks
! This choice impacts how applications are designed

15. IPv6 => IPv4
Transition Mechanisms
• 6in4
• 6to4
• NAT64
• TEREDO
• 6over4

16. IPv6 networks in a IPv4 World
REALITY: The Internet is still
predominantly IPv4
! The switch to IPv6 is not a transparent move
! Packets exchanged between IPv6 and IPv4 nodes
need modifications
! There are several options for the co-existence of
IPv6 systems with the IPv4 backbone.

17. 6in4 tunelling
! Packet tunelling of IPv6 packets through IPv4
! Transparent to the applications
! Requires End-to end control of the implementation
Source: http://www.sixscape.com/joomla/sixscape/index.php/technical-backgrounders/tcp-ip/ip-the-internet-protocol/
ipv6-internet-protocol-version-6/transition-mechanisms-from-ipv4-to-ipv6/tunneling/6in4-tunneling

18. 6to4 translation/encapsulation
! Use of prefix 2002: to identify 6to4 packets
! Connect IPv6 Islands and Internet sections through
IPv4 backbones
! Standard gateways can route 2002:: prefixed packets
! Packets have an overhead due to encapsulation
Source: Wikipedia

19. NAT64 translation
! Connects IPv6 clients to IPv4 servers
! Is frequently a stateful dynamic translation
! Can be paired with DNS64 to provide the stateful translation
! The IPv4 address is carried into a 32bit field on the 64:ff9b::/96
IPv6 address
Source: Wikipedia

20. TEREDO
! Host-to-Host tunelling for IPv6 over IPv4
! Uses standard IPv4 UDP packets for encapsulation
! Can withstand multiple layers of standard NAT
! Completely transparent for the routing IPv4
environment
Source: http://technet.microsoft.com/en-us/library/bb457011.aspx

21. 6over4 Virtual Link Layer
! IPv4 used as a virtual Link Layer
! Supports IPv6-ND over the IPv4 network
! Requires IPv4 Multicast which is not widely used
Source: http://www.cisco.com/web/about/ac123/ac147/downloads/customer/internetprotocoljournal/ipj_3-1/images/Fig_IV1.gif

22. IPv6 networks in a IPv4 World (2)
! Integration of IPv6 applications into the IPv4 Internet is
not a transparent issue
! Designers must decide what translation mechanism to
use during Design Time
! Depending on the choice, specific physical routing
gear must be deployed
! IPv6 address selection impacts on the chosen
translation mechanisms
! Specific configuration of the gateways and host
applications must be applied

23. Application Example
Integration of an Android App with a 6loWPAN Embedded
Application
(Smart Lighting)

24. Application Example
! The application example is a simple Android App
that employs direct P2P connection with a
6loWPAN network of Smart Street Lampposts.
! In this application, a WiFi router is used to connect
to the loWPAN
! The chosen transition mechanism in this case is
6to4
! Device enumeration and service discovery using
2002:: prefixes for the loWPAN nodes
! This is a contrived example, that limits the Android
node to link-local due to current Android limitations

25. Device and Service Discovery
Devices:
! Discovery of 6loWPAN border routers via multicast
IPv6 (ad-Hoc)
! FF02::1 – link local multicast address used by
Android app
! All border routers present in the same link will
respond and enumerate

26. Device and Service Discovery (2)
Services:
! SSDP – Simple Service Discovery Protocol
! Uses HTTPU (HTTP over UDP)
! Devices advertise services by multicast IPv6 at
port 1900
! SSDP is a powerful means of interoperability
! Supported by all major Operating Systems

27. Android and IPv6
Current version (Kitcat 4.4.4) has partial support for IPv6
! There is a race condition between the Kernel and
dhcpcd in Android, which leads to conflict between
DHCPv6 and the link-local address configured by the
kernel
! In this example application, we decided to disable
DHCPv6, and used the SLAAC configured fe80:: link
local address
! This is a least-effort implementation
! The resulting connection is limited to link-local, i.e., to
the WiFi router visibility

28. CoAP
! Constrained Application Protocol
! UDP-based
! RESTful (Representational State Transfer)
! Binary encoding
– Small frames
– Easy to parse
! Supports Multicast
! Application-layer: must be designed into the App
as an End-to-end concern

29. CoAP
! Easily translated to HTTP
! Extensible
! TLV – Type-Length-Value
! jCoAP
– https://code.google.com/p/jcoap/
Source: KOVATSCH, Matthias. VERMILLARD, Julien.
Hands-on with CoAP. France: EclipseCon, 2014.

30. Example App

31. Final Thoughts
Integration of IPv6 Embedded Applications require
informed Design-Time decisions regarding the
Network deployment
The choices have an impact on the Embedded
Application and the peer connected application
Knowledge of idiosyncratic behaviors of the Network
elements (stacks, OS, routers) is necessary

32. Thank You
Jonny Doin
CEO - GridVortex
jonnydoin@gridvortex.com