A Monitoring System for Edge Infrastructures

The Guifi.net network has grown over the past 15 years as a technological, social and economic project to provide Internet access nowadays to more than 80.000 people. This infrastructure was initially built with WiFi radio connections and, nowadays, also employs fibre optic links to reach thousands of households. The monitoring system currently in place is lagging behind the network evolution, requiring manual intervention and exposing a number of single points of failure. The technology provided by the LightKone project is helping UPC to develop a novel network monitoring system built with distribution, decentralisation and automation in mind that will take over the legacy one.

Introduction

Community networks such as Guifi.net are bottom-up, citizenship-driven technological, social and economic projects with the objective of creating an open, free and neutral telecommunications network based on a commons model. The whole infrastructure can be understood as a crowd-sourced, multi-tenant collection of heterogeneous network devices (wired and wireless), interconnected and with an organised IP addressing scheme. In particular, Guifi.net was born 15 years ago in Gurb, a rural village 70 km north of Barcelona, to overcome the lack of Internet access provision by the incumbent ISPs back then. As of today, the network consists of more than 35.000 operational nodes, including thousands of kilometers of fiber optics links, it covers most areas of Catalonia and is also present in several regions of Spain. Figure 1 captures Guifi.net around Barcelona and surrounding towns. Providing Internet access to more than 80.000 people, it is considered to be the largest community network worldwide.

Besides the network equipment such as routers, in Guifi.net there is a computing infrastructure located at the network edge. It is formed by a collection of heterogeneous computing devices ranging from single-board computers (SBCs), such as the popular Raspberry Pi, to mini-computers and desktop PCs. Most devices are located at users’ homes or in the premises of municipalities. These devices usually have the Cloudy platform installed on them to provide both network-related and user-targeted services.

The current monitoring system in Guifi.net is built around a centralized database that contains a list with all the network devices, all the monitoring servers, and the assignations between them (i.e., which monitor is in charge of each device). Monitors are geographically spread over the network, and the assignations are manually decided through the Guifi.net website. During normal operation, each monitoring server fetches its assigned devices list and periodically checks them for their status (response time, traffic on their different network interfaces, etc.). The collected data are stored locally at each server, available for visual inspection, by means of specific API-like calls performed through the main Guifi.net website. This current monitoring system, while in general terms works and accomplishes its duties, has important limitations regarding its robustness and resilience to cope with varying conditions of the network and its infrastructure. In particular, it does not deal properly with network partitions, in case a monitor ceases to operate (e.g., due to a hardware failure) the devices assigned remain unmonitored and collected data are stored at a single location without redundancy. Within the LightKone project, we have designed and implemented a new monitoring system for Guifi.net that overcomes the current one’s limitations by making use of the technologies the project has developed. This article describes its most remarkable aspects.

For a complete article, read the post published Medium.

By Roger Pueyo Centelles, Mennan Selimi, Felix Freitag, and Leandro Navarro, Universitat Politècnica de Catalunya