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Networking Solutions for Connecting Bluetooth Low
Energy Enabled Machines to the Internet of Things
Johanna Nieminen TeliaSonera
Carles Gomez and Joaquim Oller
University Politecnica de Catalunya/Fundacio i2CAT,
Markus Isomaki, Teemu Savolainen, Minjun Xi Nokia,
Basavaraj Patil AT&T Mobility,
Zach Shelby ARM
2015. 3. 23
최무준
Department of Computer Science and Engineering
Engineering, Sogang UniversityPage 1 / 12
Page 1
CAD & VLSI Lab. Youse Kim
INDEX
• Bluetooth LE Overview
• A proposal for enabling IPv6 over Bluetooth LE
• Performance of the Proposed Solution
• Security
• Router and Gateway operation
• Conclusion
Department of Computer Science and Engineering
Engineering, Sogang UniversityPage 2 / 12
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CAD & VLSI Lab. Youse Kim
Bluetooth Low Energy Overview
• Designed for ultra low-power application
• Keeping similarity with classic Bluetooth
• Major changes in Bluetooth protocol
• Bluetooth LE protocol stack
– Physical layer
• Use adaptive Frequency Hopping
Spread Spectrum(FHSS)
– Link layer
• Specify bidirectional connection
Figure 1. Bluetooth LE native protocol stack(left)
And IPv6-based Bluetooth LE stack (right)
– Logical Link Control and Adaptation Protocol(L2CAP)
• Multiplexes upper layer
• Perform segmentation, retransmission, detection of packet
– Generic Access Profile, Generic Attribute Profile, Attribute protocol
• Allow applications to communicate and request data
Department of Computer Science and Engineering
Engineering, Sogang UniversityPage 3 / 12
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CAD & VLSI Lab. Youse Kim
A Proposal for IPv6 over Bluetooth LE
• Using IPv6 for connecting Bluetooth LE nodes to IoT devices
• Designed a solution for enabling and optimizing IPv6 Bluetooth LE
• Enabling and Optimizing IPv6 over Bluetooth LE
– Reusing 6LoWPAN
• 6LoWPAN (IPv6 over Low power Wireless Personal Area Networks)
–
–
–
–
–
Designed as a adaptation layer between IPv6 and 802.15.4
Defines 6LowPAN Router(6LR) and 6LoWPAN Border Router(6LBR)
Defines IPv6 datagram fragmentation and reassembly over 802.15.4
Supports for stateless and stateful header compression
Offers the optimized ND protocol for 6LoWPAN
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CAD & VLSI Lab. Youse Kim
A Proposal for IPv6 over Bluetooth LE
• Technical decision on this proposal for using IPv6 over Bluetooth LE
– Device roles and Network scenarios
• Slave and master play a role of host and 6LBR, respectively
• Two network scenario are possible
–
Bluetooth LE is connected to the Internet
–
Bluetooth LE network may be an isolate network permanently
Figure2. a) Internet connected
b) Isolated Bluetooth LE network
– Protocol Stack
• 6LoWPAN (adapted to Bluetooth LE) is inserted between IPv6 and
Bluetooth LE L2CAP
• Facilitate coexistence of the native and IPv6-based Bluetooth LE
• L2CAP fragmentation mechanisms are still available to IPv6
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Engineering, Sogang UniversityPage 5 / 12
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CAD & VLSI Lab. Youse Kim
A Proposal for IPv6 over Bluetooth LE
• Technical decision on this proposal for using IPv6 over Bluetooth LE
– IPv6 Address Autoconfiguration
• IPv6 addresses are composed of a prefix and an interface identifier (IID)
• IPv6 link-local addresses are formed by appending the IID to link-local
unicast prefix
• Global IPv6 address are formed by prepending a valid prefix to the IID
– Neighbor Discovery in Bluetooth LE
• Use simplified version of 6LoWPAN ND
– Header compression over Bluetooth LE
• Use header compression in 6LoWPAN for 802.15.4, except for IPv6
address compression
• In link-local communication over Bluetooth LE, 40-byte IPv6 header
can be reduced down to 2 bytes
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Engineering, Sogang UniversityPage 6 / 12
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CAD & VLSI Lab. Youse Kim
A Proposal for IPv6 over Bluetooth LE
• Technical decision on this proposal for using IPv6 over Bluetooth LE
– Fragmentation in Bluetooth LE
• Bluetooth LE is not supporting the transmission of 1280 byte
• L2CAP layer has two mechanisms (SAR and FAR) that consume bytes
SAR : Segmentation and Reassembly
FAR : Fragmentation and Recombination
Figure 3. Encapsulation of large IP datagrams in multiple Bluetooth LE packets: a) L2CAP modes
that support SAR; b) basic L2CAP Mode + FAR. Data unit field sizes are expressed in bytes.
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CAD & VLSI Lab. Youse Kim
Performance of the Proposed Solution
• Evaluate energy/power consumption, throughput and latency
• Considering several IPv6 header compression scenarios and the
two lowest-overhead L2CAP modes for fragmentation
• Master : modified Nokia N9 smartphone
• Slave : CC2540 chipset developed by Nokia Research Center
• Physical Layer, Link Layer, L2CAP was implemented
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CAD & VLSI Lab. Youse Kim
Performance of the Proposed Solution
• Energy and Power Comsumption
Figure4. Energy cost of communicating an IPv6 datagram
over a Bluetooth LE link versus its payload size,
Figure5. Average power consumption during a connection
interval and connection event duration versus
the connInterval parameter
– Fig. 4 shows header compression provides significant benefits
– Fig. 5 shows the average power consumped by the slave
decreases as the connInterval parameter increases
– Fig. 5 shows the duration of the active part increases
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CAD & VLSI Lab. Youse Kim
Performance of the Proposed Solution
• Throughput
Figure 6. IPv6 throughput over an ideal
Bluetooth LE link versus IPv6 datagram
payload size, for different L2CAP and IPv6
header compression scenarios.
– Fig. 6 shows the achievable throughput is lower than the
theoretical one
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CAD & VLSI Lab. Youse Kim
Performance of the Proposed Solution
• Throughput
Figure 7. Latency of a CoAP request-reply exchange over a Bluetooth LE
link. Average and standard deviation results are plotted.
– Fig.5 and Fig. 7 illustrate the trade-off between latency and
power consumption, which depends on connInterval setting
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CAD & VLSI Lab. Youse Kim
Security
• Bluetooth LE network has a various type of threats and attack
• IPv6 over Bluetooth LE use Bluetooth LE security mechnisms
– IPv6 datagram is protected by Bluetooth LE link layer security
– Cipher Block Chaining-Message Authentication Code(CCM)
– 128-bit AES block cipher
– 4-byte Message Integrity Check(MIC) is included in packets
• Bluetooth LE security requires the device to perform pairing
– Bluetooth Security Manager Protocol(SMP) is used for carrying
out the paring and key distribution procedure
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CAD & VLSI Lab. Youse Kim
Router and Gateway Operation
• Bluetooth LE-enabled IoT devices communicate to the Internet via
a gateway, for example a mobile phone or a home router.
• The gateway is a plain IP router that implementation a role of 6LBR
• IP Router Function
– A gateway has to obtain global IPv6 prefixes to number IoT
devices with IPv6 address
– Gateway use a set of tool that depends on a type of Internet
– DHCPv6 Prefix Delegation(PD) is the most suitable tool for
obtaining prefixes for networking numbering
– Instead of DHCPv6 PD, utilize some of IPv6 trasition tools
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Engineering, Sogang UniversityPage 13 / 12
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CAD & VLSI Lab. Youse Kim
Router and Gateway Operation
• Application Layer Function
Figure 8. A gateway connecting IoT devices to the Internet
can operate as a 6LBR/IP router or have additional
application functions. L2 stands for Link Layer.
Figure 9. Influence of a cache on the average power
consumption of a CoAP server over Bluetooth LE
– Fig. 9 shows the power saving of using a cache increase as the
time between requests decrease
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CAD & VLSI Lab. Youse Kim
Conclusion and Future Work
• It is possible to enable end-to-end IP connectivity for Bluetooth device
• Proved the feasibility of implemeting the solution
• Showed performance trade-offs configuration of Bluetooth parameters
• Open issues
– Evaluating additional header compression mechanisms
– IoT device management
– Optimizing mobile gateways by adapting their Internet connectivity
link to support IoT traffic
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CAD & VLSI Lab. Youse Kim