Crowdsourced computer networks refers to network infrastructure built by citizens and organisations who pool their resources and coordinate their efforts to make these networks happen. Community networks are a subset of crowdsourced networks that are structured to be open, free and neutral. In these the infrastructure is contributed by the participants and is managed as a common resource. Many crowdsourcing experiences have flourished in community networks. This paper discusses the case of guifi.net, a success case of a community network daily used by thousands of participants, focusing on its principles and the crowdsourcing processes and tools developed within the community, the role they play in the ecosystem that is guifi.net nowadays, the current status of its implementation, its measurable local impact, and the lessons learned in more than a decade.

This work presents a technological analysis of guifi.net, a free, neutral, and open-access community network. Guifi.net consists of more than 27,000 operational nodes, which makes it the world's largest community network in terms of the number of nodes and coverage area. This paper describes the characteristics of the network, the link level topology, its growth over a decade, and its resilience in terms of availability and reachability of network nodes. Our study is based on open data published by guifi.net regarding its nodes and wireless links, monitoring information, community database, and its web portal. The data includes historical information that covers the lifetime of the network. The scale and diversity of the network requires a separate analysis of the subsets of the entire dataset by area or by separating the core from the leaf nodes. This shows some degree of diversity in local characteristics caused by several demographic, geographic, technological, and network design factors.We focus on the following aspects: technological network diversity, topology characteristics, evolution of the network over time, analysis of robustness, and its effect on networking service availability. In addition, we analyse how the community, the technology used, the geographical region where the network is deployed, and its self-organised structure shape the network properties and determine its strengths and weaknesses.The study demonstrates that the guifi.net community network is diverse in technological choices for hardware, link protocols, and channels and uses a combination of routing protocols yet provides a common private IP network. The graph topology follows a powerlaw distribution for links in regions up to a few thousand Km 2 , limited to the scope of wireless links. Network growth has two aspects: a geographic growth of the network core using long distance links with wireless or fibre, and the local growth in density with leaf low-cost leaf nodes. The resilience of the network derived from the nodes' uptime and the structure of the graph varies across different regions with more fragile leafs than core nodes and diverse degrees of graph resilience to random failures or coordinated attacks, such as natural causes, depending on the network planning, structure, and maturity. The guifi.net community network results from a loosely coupled and decentralised organic growth that exhibits large local differences, diverse growth, and maturity under a common community license and social network.

This work is licensed under a Creative Commons "Attribution-NonCommercial-NoDerivatives 4.0 International" license.

Community networks have flourished around the world as complementary models for enabling access to the Internet and its services. Nevertheless, there is still an ongoing debate on how to make them sustainable and scalable beyond voluntary efforts and non-refundable contributions. The approach taken by Guifi.net has been to enable professional activity and to develop a set of tools to ensure the reinvestment of a fraction of the benefits of this professional activity. This has contributed to building the largest community network, with an annual turnover of millions of euros and the creation of dozens of direct jobs. The implementation of these tools is producing extensive data sets that allow characterisation of key parameters in the deployment and operation of these infrastructures to examine behaviours and trends and to identify good and bad practices, fraud, etc. A more detailed knowledge of the economic aspects has a positive effect on reducing the uncertainty of investments, expansion plans, and operations.

Community networking is an emerging model of a shared communication infrastructure in which communities of citizens build and own open networks. Community networks offer successfully IP-based networking to the user. Cloud computing infrastructures however, while common in today's Internet, hardy exist in community networks. We explain our approach to bring clouds into the Guifi.net community network. For this we have started integrating part of our cloud prototype into the Guifi.net community network management tools. A proof-of-concept cloud infrastructure is currently under deployment in the Guifi.net community network. Our long term vision is that the users of community networks will not need to consume cloud applications from the Internet, but find them within the community network.Peer ReviewedPostprint (published version