Periodic Reporting for period 2 - LightKone (Lightweight Computation for Networks at the Edge)
Berichtszeitraum: 2018-07-01 bis 2019-12-31
The LightKone project is developing a new Edge Computing model for general-purpose computation in which computations can be done directly at the edge. This is in contrast to existing Edge Computing models which are based on the cloud: in existing models edge data is aggregated and sent to the cloud where the computations are done, and decisions are sent back to the edge. In the LightKone model, the computations are done directly at the edge, which makes it more scalable and flexible, preparing it for the future where the edge will continue to grow faster than the cloud.
We provide a single unified reference architecture for the cloud-edge spectrum, called LiRA (LightKone Reference Architecture), published in a white paper as an extension of the OpenFog Reference Architecture. Our architecture is practical because we focus on data and not on the cloud. Data is managed throughout the cloud-edge spectrum following two principles of data consistency, namely decentralized lateral data sharing (between devices in the same layer on the spectrum) and convergent vertical data semantics (between devices in different layers on the spectrum). In the final project period, we implement this reference architecture as three released application frameworks, AntidoteDB, Achlys, and Legion, which cover widely different parts of the cloud-edge spectrum. It is impractical and unwieldy to cover this spectrum with a single platform, since it would greatly encumber our progress with little advantage. Instead, we have three application development platforms that provide a coherent service and overlap in functionality where this is necessary. First AntidoteDB, which is a causally consistent transactional data store based on CRDTs and extended for the edge. Antidote supports a new programming methodology called Just-Right Consistency. Second Achlys, which is an application platform for edge applications that run directly on the sensor networks themselves. Achlys contains a task model for defining applications, a resilient CRDT-based data store called Lasp, and a resilient communications library using hybrid gossip called Partisan. Achlys runs on highly dynamic networks using highly resilient communication and is able to perform dataflow computation within the store while maintaining resilience. Third Legion, which is a platform for developing mobile Web-based applications based on shared objects containing CRDTs inside mobile phones. Legion uses peer-to-peer communication between mobile nodes to reduce latency, and the use of CRDTs guarantees data consistency.
In addition to the three application frameworks, we have released the GRiSP embedded programming platform and the Yggdrasil network protocol development framework. GRiSP consists of software and hardware that allows Internet-of-Things applications to run directly on embedded systems boards on the sensor networks themselves. GRiSP provides out-of-the-box support for standard Pmod sensors and actuators and the full Erlang OTP programming system, allowing the fast and efficient prototyping of robust edge applications. Yggdrasil is a software framework that allows developing efficient network protocols, including hybrid gossip communication, directly for ad hoc wired and wireless networks. Yggdrasil and Achlys are ported on the GRiSP embedded programming platform, thus providing an innovative powerful and comprehensive development platform for edge applications.