6LoWPAN enables the use of IPv6 in low power wireless networks by providing an adaptation layer between IEEE 802.15.4 and IPv6. It addresses issues like large IPv6 header sizes, fragmentation, and mobility through techniques like header compression and micro-mobility support. By allowing wireless embedded devices to connect using standard IPv6 protocols, 6LoWPAN helps foster interoperability and is an important foundation for enabling the Internet of Things.

1. 6LoWPAN
Martin Abraham

2. 6LoWPAN
 IPv6 over Low Power Wireless Area Networks
 Level 2/3 Protocol (OSI)
 Enables usage of IPv6 by wireless embedded devices
 Described in IETF RFC 4919, 4944

3. Device characteristics
 Dedicated to specific task/ not general purpose like PC
Limited hardware resources:
 Low processing power
(microcontroller/ dsp)
 Little memory  Low power
Limited networks capabilities:
 Short range  Low bitrate  Message-Size

4. Usage scenarios
 Building automation
 Industrial automation
 Logistics
 Enviromental Monitoring
 Personal/ Health Monitoring
 Etc.

5. Personal Monitoring

6. Industrial Automation

7. Home Automation

8. Protocol history
 1980s: Cabled networking
- not everthing can be cabled - expensive
 Mid 1990s: ~ 20 proprietary solutions (Z-Wave)
- scalibility - no interoperability (vendor lock)
- bound to specific data-link layer
 2003+: ZigBee (IEEE 802.15.4 based)
+ first wireless standard
- scalability (small scale isolated ad hoc networking)
- bound to specific data-link layer - not long-lived (quick changes)

9. Why IPv6?
 Long-lived technology (20 years+)
 Ability to connect heterogeneous networks
 Existing worldwide free-to-use infrastructure
 Global scalability
 2^128 Bit (16 Byte) Addressing = Enough for Internet of Things
 Great number of tools (diagnostic, management etc.)

10. IPv6 Problems
 Bandwidth and Energy efficiency
Standard protocol: IEEE 802.15.4 L1/L2
(low bandwidth: 250 kbps, low power: 1mW)
 Fragmentation:
IPv6 minimum frame size (MTU) = 1280 bytes
IEEE 802.15.4 frame size (MTU) = 127 byte (higher bit error rate,
failure proneness)
 Header compression:
IPv6 headers (40 bytes) reduce payload
53 byte payload in 127 byte 802.15.4 frame

11. IPv6 Problems
 Mobility:
Node Mobility and Network Mobility
 Review of Transport Layer Protocols:
TCP inefficient for wireless embedded devices (wireless packet lost)
 Handle offline devices:
IP assumes devices are always on, but embedded devices may not
(power and duty cycles)
 Multicast support:
IEEE 802.15.4 & other radios do not support Multicast (expensive)

12. 6LoWPAN

13. Fragmentation
 Datagram = Basic transfer unit (header, payload)
 3 fragmentation header

14. Fragmentation
 Datagram-size: 11bit = 2047 > 1280byte (mininmal IP MTU)
Transmitted in every fragment.
Destination can reserve memory on first arrival for the whole message
 Datagram-tag: 16 bit
Sufficient for limited link speed (min. 4 min for repeat)
 Datagram-offset: 8 bit
Offset addressed in 8byte units  2047bytes addressable by 8 bit
 Longer messages?
Fragmentation handled by standard ip fragmentation (L3)  awsome!

16. Header compression

17. Compress IPv6 headers
 HC1: IP header
 HC2: UDP header
 Reduce header size by omission
Omit headers that...
 can be reconstructed from L2 layer headers (redundant)
 contain information not needed or used in the context (unnessecary)

18. IPv6 header (6LoWPAN header)

19. HC1 – Compress IPv6 address
 IPv6 address: 64bit prefix | 64bit interface id
Remove IPv6 address-prefix:
 All nodes in a PAN share single prefix
 PAN ID maps to IPv6 prefix
Remove IPv6 Interface ID (IID) for local communication:
 IID generated from EUID64 (L2)

20. 6LoWPAN Architecture

21. Mobility
 Micro-Mobility:
stay in same ip-domain
e.g. switch edge router inside extended 6LoWPAN network
 Node-Mobility:
Node moves physically between different 6LoWPAN networks
e.g. attached to a parcel
 Network-Mobility:
Full 6LoWPAN networks switches backhaul link
handled by edge router

22. Communication/ Bootstrapping
Handle offline devices:
 Node-initiated communication (to deal with sleep cycles etc.)
Bootstrapping/ Multicast/ device constraints:
 Roles: Router, Nodes, NEW: Edge Router (take load of devices)
 Node Registration/ Node Confirmation replaces Multicast
 Duplicate Address Detection done by Edge Router

23. Conclusion
6LoWPAN...
 is an open standard
 provides an adapter between IEEE 802.15.4 (L1/2) and IPv6 (L3)
 enables interoperability between wireless embedded devices (and
common Internet devices) using standard protocols
 fosters standardization of communication in scope of wireless embedded
devices
 provides an important foundation for the Internet of Things (IoT)