The LPWAN Server is meant to be a flexible wrapper around the numerous IoT data delivery networks. To enable this flexibility, parts of the system support a plug-in architecture that allows for future expansion. In some cases, these expansion areas correspond with others (e.g., UI support for entering custom data for a network).
The Application Vendor uses the UI to interact with the system. The UI uses the REST API of the REST Server to access and update data. The REST Server then communicates with the remote network via the Internet. The remote networks pass data back, and the data is passed to the Reporting Protocols that send the data back to the Application Vendor's server(s).
Points of Customization
Note that there are four points of system customization:
Network Protocols - Each remote network may have a unique API that the REST Server uses. Some of these remote networks may also share APIs. New Network Protocols can be added to support new APIs as new servers join the LPWAN Server ecosystem.
Reporting Protocols - Application vendors will receive data from the REST Server. The mechanism of sending what data can be customized on a per-application level.
Database Adapters - LPWAN Server uses Prisma for the database layer. Prisma currently supports a few different databases, with many on the roadmap. LPWAN Server uses Postgresql as the default, but with simple modifications, LPWAN Server can be deployed with any database supported by Prisma.
UI Customizations - UI customizations can be made so data specific to a network type can have a unique user interface. For example, LoRa networks identify devices using an 8 byte binary value known as a DevEUI, where an NB-IoT network may use an IMEI, such as the one used by a mobile phone. This data is known to and used by the Network Protocols and passed to the remote networks. Currently deployed with the software:
- LoRa - Specifies the data specific to the networks supporting the LoRa protocols.
- IP - Supports a UI specific for IP-based devices.
- Default - A general purpose data specification format, where data is specified in the expected internal JSON format for the network type. This code is a last resort UI, for when the network-specific UIs are not available. The Default UI should not be seen in a production system.
The Data Model
The LPWAN Server data model is meant to be a general model that can represent the data of many remote networks, while providing significant customization for each type of network. The following outlines the basic elements of the system and how they interact:
Users - Usernames and passwords to log in to the system. Users can be "Admin", which gives them global rights to access and modify records. Normal users have permission to access and modify data that they've created.
Applications - The functional grouping of Devices that all serve essentially the same purpose, reporting the data back to a remote server. Applications report the data collected from Devices to some network server using a ReportingProtocol.
Devices - The devices that collect and report data back to the application. Devices often communicate via a specific NetworkType, though multiple NetworkTypes could be supported if the Device has the necessary hardware. Device settings are generally specified by a DeviceProfile.
DeviceProfiles - A collection of settings for Devices for a particular NetworkType. If a Device supports multiple NetworkTypes, each will use a different DeviceProfile.
Networks - The remote networks that the LPWAN Server uses to configure and access data from Devices. A Network has a base URL for communications with the Network, a NetworkType, basically defining the data that is relevant to the Network, and a NetworkProtocol that defines the API used to communicate with the Network. In addition, the Network includes data that is used to validate access with the remote network, which is defined by the NetworkType.
NetworkTypes - A way of collecting Networks into a common data configuration scheme. When provisioning Applications, Devices, or DeviceProfiles via the UI, the NetworkType selection enables custom UI elements that allow for providing this data. To allow the database to store this potential varying data, it is placed into the record as a JSON object string. When communicating with the REST interface, this data can be found in the Network, ApplicationNetworkTypeLink, DeviceNetworkTypeLink and DeviceProfile records. It is left to the caller of the REST API to provide the data expected for each NetworkType. This data is consumed by the NetworkProtocol for a Network to provision the remote network.
ApplicationNetworkTypeLinks - Links basic application data defined in Applications to a specific NetworkType, and includes the custom data for that NetworkType. Creation of an ApplicationNetworkTypeLink causes the system to call the NetworkProtocol for the remote networks of that type, provisioning the application data on the remote system.
DeviceNetworkTypeLinks - Links basic device data defined in Devices to a specific NetworkType, and includes the custom data for that NetworkType. Creation of a DeviceNetworkTypeLink causes the system to call the NetworkProtocol for the remote networks of that type, provisioning the device data on the remote system.