Section: New Results

6TiSCH Standardization and Benchmarking

Minimal Security Solution

Participants : Malisa Vucinic, Thomas Watteyne.

The 6TiSCH standardization effort had, until 2017, a big gap: security. Thanks to the work of Malisa Vucinic, this gap is now filled, with the publication of the Minimal Security solution (draft-ietf-6tisch-minimal-security). Here is a summary of what has been implemented and tested:

• Two implementations of the OSCORE protocol, formerly known as OSCOAP, specified in draft-ietf-core-object-security-03, in C and in Python, supporting both client and server roles, as part of the OpenWSN stack. Updated the test suite of the Python implementation with OSCOAP functional tests.

• Two implementations of Simple Join Protocol for 6TiSCH, specified in draft-ietf-6tisch-minimal-security-03, in C supporting the role of a pledge and in Python, supporting the role of JRC. Written unit tests for the implemented CBOR decoder in C.

• Simulation of the join process in 6TiSCH simulator. Extended the simulator to support shared cells, downwards RPL routing and join traffic. Tested the two implementations of Simple Join Protocol/OSCOAP using the F-Interop tools.

OpenWSN Fresh with full 6TiSCH Support

Participants : Tengfei Chang, Thomas Watteyne.

Thanks to the incredible work of Tengfei Chang, the OpenWSN project was refocused on being the lead reference 6TiSCH implementation. “OpenWSN Fresh” was a 2017 program to separate the protocol stack implementation from the rest of the OpenWSN code, and to have full standards-compliance.

First F-Interop 6TiSCH Interop Event

Participants : Remy Leone, Tengfei Chang, Malisa Vucinic, Thomas Watteyne.

The 6TiSCH WG organized an interoperability event co-located with the IETF meeting in Prague in July 2017. The interop tests focused on the minimal security framework and the 6top protocol. OpenWSN was used as the reference implementation, and F-Interop tools were demonstrated.

Agile Networking

Participants : Jonathan Munoz, Thomas Watteyne.

Today's low-power wireless devices typically consist of a micro-controller and a radio. The most commonly used radios are IEEE802.15.4 2.4GHz, IEEE802.15.4g sub-GHz and LoRA (SemTech) compliant. Radios offer a different trade-off between range and data-rate, given some energy budget. To make things more complex, standards such IEEE802.15.4g include different modulations schemes (2-FSK, 4-FSK, O-QPSK, OFDM), further expanding the number of options.

The main idea behind agile networking is to redefine a low-power wireless device as having multiple radios, which it can possibly use at the same time. That is, in a TSCH context, for each frame a node sends, it can change the radio it is using, and its setting. If the next hop is close, it sends the frame with a fast data rate thereby reducing the radio on-time and the energy consumption. If the next hop is far, it uses a slower data rate.

We recently design the OpenMote B within the OpenMote company. This board contains both a CC2538 IEEE802.15.4 radio, and an AT86RF215 IEEE802.15.4g radio, offering communication on both 2.4GHz and sub-GHz frequency bands, 4 modulations schemes, and data rates from 50 kbps to 800 kbps. The first prototypes started being tested in December 2017.

The second challenge is to redesign the protocol stack in a standards-compliant way. We are working with Jonathan Munoz on a 6TiSCH design in which neighbor discovery happens independently on each radio, and the same neighbor node can appear as many times in the neighbor table as it has radios. The goal is to standardize an “Agile 6TiSCH” profile, without having to touch the core specifications. This is been implemented in OpenWSN. The next step is to evaluate the performance of the solution on an 80-node OpenMote B testbed we are putting together. We hope to show that a single device running the same stack can satisfy both building-size and campus-size deployment, with the same industrial requirements.