6LoWPAN Interoperability
Jonathan Hui
Zach Shelby
David Culler
07/24/2007
69th IETF Meeting - 6LoWPAN WG
1
Motivation
• 6LoWPAN format doc approved as Proposed Standard
• Several 6LoWPAN implementations
– Had not yet seen independent implementations interoperating
– No excuse even if some protocols are TBD
• Demonstrating interoperability of the format doesn’t require them
• Pin down routing tables, manually assign configurations
• To elevate to Draft Standard, need to show independent
implementations interoperating
• Need a framework to start thinking about interoperability
07/24/2007
69th IETF Meeting - 6LoWPAN WG
2
Format Complexity
• 6LoWPAN format takes many forms, cross-product of:
– Adaptation Layer
• Short vs. extended addresses
• Dispatch, Mesh, and Fragmentation header
• Escape values for dispatch and hop limit
– LOWPAN_HC1
• Prefix compression (source and dest)
• Interface identifier compression (source and dest)
• Traffic Class and Flow Label
– LOWPAN_HC2 (HC_UDP)
• Port compression (source and dest)
• Length compression
 Thousands of permutations!
– The same header can take multiple forms
07/24/2007
69th IETF Meeting - 6LoWPAN WG
3
Beginnings of Interop Testing
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Not all forms can be tested in all situations, so lets layer it
– Mesh, broadcast, and fragmentation still to be added
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Level 0 – Establish that we are talking IPv6 (uncompressed)
– Level 0.0
• Link-local communication
• Extended source and destination 802.15.4 addresses
• No mesh or fragmentation header
– Level 0.1
• Global communication
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Level 1 – Communication over LOWPAN_HC1
– Level 1.0
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Link-local communication
Extended source and destination 802.15.4 addresses
No mesh or fragmentation header
Maximally compressed (no addresses in IP header)
– Level 1.1
• Global Communication
07/24/2007
69th IETF Meeting - 6LoWPAN WG
4
A Long Ways to Go!
• A small step for the 6LoWPAN format
• Interoperability will eventually encompass other
6LoWPAN protocols as well:
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Configuration
Routing
Forwarding
Multicast
• Some things to keep in mind as we move forward…
07/24/2007
69th IETF Meeting - 6LoWPAN WG
5
Interoperability between…
• Two embedded nodes in the same PAN?
• Two embedded nodes in different PANs?
• An embedded node and a gateway/router?
• An embedded node an any arbitrary IP device?
• Yes to all of these, of course
07/24/2007
69th IETF Meeting - 6LoWPAN WG
6
Interoperability over…
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•
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IEEE 802.15.4 beacon mode or non-beacon mode?
Basic CSMA without PAN coordinators?
GTS? Other TDMA?
Power management?
 802.15.4 does not define power management in peer-to-peer
• 6LoWPAN is taking a non-traditional approach
– Tight integration with layer 2: assumes 802.15.4 headers
• The 6LoWPAN format is MAC/power management agnostic
– But, starting to making some suggestions/assumptions about the
existence of beacons and PAN coordinators
– Should be careful when making assumptions about the underlying MAC
07/24/2007
69th IETF Meeting - 6LoWPAN WG
7
Summary
• 6LoWPAN interoperability testing considerations
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Embedded nature of nodes
MAC layer options and settings can affect interoperability
LoWPANs operating in isolation or as part of larger IP networks
Future interoperability
• Format relies on 802.15.4 header, but can operate over different
MAC configurations
• Next steps
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Extend interop levels to cover entire 6LoWPAN format
Addition of test cases
Release of example test code
Encouragement of interop testing between implementations
07/24/2007
69th IETF Meeting - 6LoWPAN WG
8
Interop Demo
(after the meeting)
• End-to-end
802.15.4
Terminal
07/24/2007
69th IETF Meeting - 6LoWPAN WG
9