Non-Intrusive Distributed Tracing of Wireless IoT Devices with the FlockLab 2 Testbed

Abstract

Testbeds for wireless IoT devices facilitate testing and validation of distributed target nodes. A testbed usually provides methods to control, observe, and log the execution of the software. However, most of the methods used for tracing the execution require code instrumentation and change essential properties of the observed system. Methods that are non-intrusive are typically not applicable in a distributed fashion due to a lack of time synchronization or necessary hardware/software support. In this article, we present a tracing system for validating time-critical software running on multiple distributed wireless devices that does not require code instrumentation, is non-intrusive and is designed to trace the distributed state of an entire network. For this purpose, we make use of the on-chip debug and trace hardware that is part of most modern microcontrollers. We introduce a testbed architecture as well as models and methods that accurately synchronize the timestamps of observations collected by distributed observers. In a case study, we demonstrate how the tracing system can be applied to observe the distributed state of a flooding-based low-power communication protocol for wireless sensor networks. The presented non-intrusive tracing system is implemented as a service of the publicly accessible open source FlockLab 2 testbed.

Grace: Low-cost time-synchronized GPIO tracing for IoT testbeds

“…From these results, we can conclude that Grace achieves a building-wide time-synchronization in the range of a few microseconds. This does not fully reach the degree of timesynchronization offered by custom solutions with specific hardware requirements or using FPGA's for the GPIO tracing [9], [10]. However, our system is easily and cost efficiently retrofittable to existing testbeds and offers a sufficient time synchronization for tracing of many application fields.…”

“…A more recent work is Flocklab 2 [10], which uses the programmable real-time unit (PRU) of a Beaglebone Green for GPIO tracing. For time synchronization, the system uses GNSS with an accuracy of approx.…”

“…There are distributed, time-synchronized GPIO logging systems implemented in existing testbeds [8]- [10]. However, they use custom hardware with FPGAs and require a specific testbed observer platform throughout the testbed.…”

Poster Abstract: Selective Flooding-Based Communication for Energy Harvesting Networks

“…We first evaluate the proposed protocol using the FlockLab [6] testbed, creating a network of 11 nodes and one host. We use an indoor solar harvesting data set [5] to estimate energy budgets at different office locations.…”

UMBRELLA: A One-Stop Shop Bridging the Gap From Lab to Real-World IoT Experimentation

“…Wireless Experimentation: With regards to wireless experimentation, some notable examples are the FIT IoT-Lab [7], FlockLab 2 Testbed [8], D-Cube [9], w-ILab [12], Cosmos Lab [16], etc. These testbeds are publicly accessible and can enable experimentation around the LPWAN area.…”