The Wireless Embedded Internet Helping the next Billion Nodes onto the Internet


CoAP, OMA LWM2M and IPSO Smart Objects

Yesterday evening at IETF 91, Michael Koster (ARM) gave a tutorial presentation of how the Constrained Application Protocol (CoAP, as specified in RFC 7252), Open Mobile Alliance (OMA) Lightweight Machine to Machine (LWM2M), and IPSO Smart Objects work together to provide wide interoperability for the application layer of the Internet of Things.

Catch the slides while they are still hot.

Or if you are in the Santa Clara area, just join a free seminar on Nov 18.

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IETF 91 and RFC 7400

6lo is on a roll (no pun with that other WG intended).

Today, RFC 7400 was published, Generic Header Compression, for removing redundancy from extension headers and header-like payloads with a very simple bytecode-based compressor.  (If you are like me, the number 7400 evokes some additional associations...  But honestly, that was just the next number in sequence.)

On October 30th, we already got RFC 7388, the LoWPAN MIB, to define the network management counters that help diagnosing and debugging a 6lo device.

Next to be published by 6lo is the IPv6 adaptation layer specification for the Z-Wave radio G.9959, LoWPANZ, approved on October 31 and currently undergoing final editing by the RFC editor.

At IETF91 in Honolulu, which finished today, we worked on a number of other adaptation layer specifications that are getting ready, including IPv6 over NFC; IPv6 for Bluetooth Low Energy (Bluetooth Smart), DECT ULE (Ultra Low Energy), IPv6 over RS485 (6lobac) are in various stages of WG processing.  We are also looking at ways to further increase the efficiency of 6LoWPAN and other 6lo networks running the RPL routing protocol.

If you want to know more, you can visit the 6lo status page.

Clearly, the transition of the 6LoWPAN work to the 6lo WG worked very well!

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IETF plans 6lo WG as successor to 6LoWPAN WG

A year ago , I mentioned that the 6LoWPAN WG, having completed its work program, is being shut down.

Of course, the work on 6LoWPAN technologies and constrained node networks continues, and a new WG for handling their Internet Area aspects is under consideration by the IETF's steering group IESG.  The proposed charter of the 6lo WG reads:

6lo focuses on Internet Area work that is needed for constrained node
networks with the characteristics of:
* limited power, memory and processing resources
* hard upper bounds on state, code space and processing cycles
* optimization of energy and network bandwidth usage
* lack of some layer 2 services like complete device connectivity and

Specifically, 6lo will work on:

1. IPv6-over-foo adaptation layer specifications using 6LoWPAN
(RFC4944, RFC6282, RFC6775) for link layer technologies of interest in
constrained node networks

2. Related MIB modules

3. Specifications, such as header compression, that are applicable to
than one adaptation layer specification

4. Maintenance and informational documents required for the existing IETF
specifications in this space.

Only specifications targeting constrained node networks are in scope. 6lo
will work closely with the 6man working group, which will continue to
work on IP-over-foo documents outside the constrained node network space
and will continue to be the focal point for IPv6 maintenance. For
adaptation layer specifications that do not have implications on IPv6
architecture, 6man will be notified about 6lo's working group last call.
Specifications that might have such an impact (e.g., by using IPv6
addresses in a specific way or by introducing new ND options) will be
closely coordinated with 6man, and/or specific parts will be fanned out
to 6man documents. Beyond 6man, 6lo will also coordinate with LWIG and

6lo works on small, focused pieces of Internet Area work. 6lo does not
take on larger cross-layer efforts. The working group will continue to
reuse existing protocols and mechanisms whenever reasonable and possible.

Security and management work that is not specific to the link layers
worked on is out of scope. Work related to routing is out of scope. 6lo
will coordinate closely with the working groups in other areas that focus
on constrained node networks, such as ROLL (RTG) and CoRE (APP).

At this point, this is at the stage of a proposal, with comments requested until 2013-10-03.  See the full announcement at the IETF announcement archive.

6lo is expected to have their first WG meeting in early November at IETF88 in Vancouver.

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6LoWPAN State of the Union

The 6LoWPAN working group of the IETF was formally instituted 7.5
years ago, in March 2005. It was reasonably quick getting its first
few RFCs published, RFC 4919 (August 2007) with the problem statement
and RFC 4944 (published September 2007, approved 2007-05-01) with the
protocol specification. This has since been extended by RFC 6282
(September 2011, approved 2011-03-29) with an improved header
compression mechanism. While yours truly was on vacation, the third
component of the 6LoWPAN set of specifications was approved
(2012-08-24): It does not yet have an RFC number (final text still
being worked on by the RFC editor), but it is fondly known as
6LoWPAN-ND (Neighbor Discovery optimizations). Multiple instances of
running code for all these specifications have existed for quite some
time, and a number of interoperability tests have demonstrated that
they work.

This means we now have a complete set of specifications for 6LoWPAN,
and the work of the 6LoWPAN WG is formally complete. We also have
submitted a specification for applying 6LoWPAN technology to Bluetooth
Low-Energy (part of the Bluetooth 4.0 specification, marketed as
Bluetooth Smart). This has not passed the IESG yet, mainly on
procedural issues; work to clear those up is ongoing.

There are other documents that are candidates for joining the 6LoWPAN
family. Instead of making this post too long, let me just point to
the 6LoWPAN roadmap, freshly updated by yours truly.

But as far as the 6LoWPAN WG is concerned, we are done. It is a good
principle of the IETF to close WGs when they have done their work, and
we can expect this to happen soon. Of course, this doesn't mean the
specifications won't receive continued attention. Further work may
happen in IETF WGs such as 6man (IPv6 maintenance), intarea (general
Internet area issues), or maybe a new, newly-focused WG if that turns
out to be justified. The mailing list will also stay
open, so this will continue to serve as a focal point for anyone
seeking to clarify, fix, or extend the 6LoWPAN set of specifications.

A number of other IETF WGs do 6LoWPAN-related work. The ROLL WG has
created a routing protocol for constrained node networks, RPL (RFC
6550). The CoRE WG is in the process of completing an application
protocol (CoAP) that does many of the things HTTP does well, with much
less complexity. The LWIG WG is trying to document some of the
implementation issues in this space. Also, some pre-WG efforts are
springing up such as COMAN (Management for constrained node networks)
and SOLACE (Smart Object Lifecycle Architecture for Constrained

Building the actual Internet of Things is going to stay exciting, and
the 6LoWPAN technologies are going to keep the central place in this,
even if we now longer need an IETF working group with that name.

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CoAP and the Web of Things

I gave a short talk about the need for CoAP in the Web of Things at the "Internet of Things Forum International" in Berlin.

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6LoWPAN and CoRE Tutorials

I just gave a lecture about 6LoWPAN at the "IAB Tutorial on Interconnecting Smart Objects with the Internet" in Prague.

Here are the slides I used:


(Update:) And here are Zach's slides on CoRE:


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Book Exercises Released

The book exercises have (finally) been released. This slide set includes an overview of embedded technology typically used in the Wireless Embedded Internet, an overview of embedded development and a short tutorial on Contiki. The slides currently include a small number of Contiki related exercises. Both the Contiki overview and exercises will be continuously updated, so check for updates!

Contiki programming exercises - Learn embedded development and 6LoWPAN programming with the open-source Contiki project

6LoWPAN Book Course Exercises (PPT) Updated 4.3.2010
6LoWPAN Book Course Exercises (PDF) Updated 4.3.2010

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Seminar Video Released

I gave a book release seminar on Dec 6th at the Centre for Internet Excellence in Oulu, Finland. Thanks to the great hosts, we are now releasing the entire seminar in a really professional format on-line. The seminar gave a good overview of 6LoWPAN and the general contents of the book, covering about half of the course material slides and lasts for 80 minutes. Enjoy!

6LoWPAN Seminar Video (80 minutes, MP4) Recorded 6.12.2009

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Lecture slides released

The companion lecture slides for 6LoWPAN: The Wireless Embedded Internet have now been released on The Book page of This first part of the book's course material includes a suggested course syllabus, and 115 of lecture slides in both PowerPoint and PDF formats. This overview of the book is a good tool for lecturers, students and professionals alike. The slides have been released under a creative commons by-nc-sa license to encourage re-use. The companion exercise slides for Contiki are planned for release in the near future.

Links to the syllabus and lecture slides:

6LoWPAN Book Course Syllabus (PDF)
6LoWPAN Book Lecture Slides (PPT)
6LoWPAN Book Lecture Slides (PDF)

We hope everyone finds these useful!

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Book Seminar in Finland

For people interested in 6LoWPAN technology in Finland, Zach will be giving a seminar with the latest news on what is happening in the industry and a technical overview of our new 6LoWPAN book. Thanks to the Center for Internet Excellence for hosting the event. Here is the information:

Tuesday December 8th, 13-15
Center for Internet Excellence
Oulu, Finland
The seminar is free of charge (and there is coffee too!)

Zach will also be teaching several long and short courses based on the book in 2010:

February 2010 - Kokkola, Finland - Chydenius Institute
Winter 2010 - Oulu, Finland - Center for Wireless Communications
June 2010 - Oulu, Finland - Ubi Summer School
Aug/Sept 2010 - Croatia - SenZations Summer School

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