## 1 Introduction  
Prospective studies state that 70% of the world population will live in cities by 2050. Following this trend, the development of telecommunications technologies supporting new services is more and more focused on urban areas. Mobile cellular networks are a clear example: While 2G was deployed targeting full coverage of most of the territory in many countries, 3G was deployed with coverage concentrated in populated areas and 4G coverage maps showing smaller spots in the main cities.  
Living conditions in isolated rural communities in developing regions are difficult because they often lack access to basic services such as electricity, water, sanitation, healthcare, and education. ICTs could be key enablers of access to some of those services, but the rural-urban digital divide gets larger and larger as new technologies assume the conditions of densely populated areas. The reason for the rural-urban digital divide is three-fold: a difficult rural geography, high poverty rates, and a highly sparse population. This leads to high infrastructure deployment costs and low expected revenues, a fatal combination that prevents telecommunication operators from investing in rural telecommunications infrastructures, at least using conventional technologies and business models.  
In this context, the EHAS Foundation has been working on real rural telecommunications projects since 2004, aiming to find the optimal conditions for deploying sustainable rural communications networks in isolated areas of several countries in Latin America, and more intensively in Peruvian regions such as the mountainous areas in the Cuzzo province and the Amazon rainforest in several parts of the Loreto region. During the last 14 years, the target of those rural telecommunications deployments has evolved from telemedicine networks to general purpose telecommunications infrastructures; technologies have evolved to enhance the robustness, the capacity, and the quality of service support; furthermore, the business models proposed have become more complex and better suited for long-term sustainability in those regions. As well, during that process, the partnerships and alliances have evolved as feedback from previous projects showed how sustainability runs into problems as it develops. a direct relationship between the structure of heterogeneous interdisciplinary partnerships and alliances and sustainability has become more and more obvious, evolving from basic yet complex three-party alliances among NGOs, universities, and public institutions, to larger, complex networks involving Mobile Network Operators (MNOs) and Small Rural Operators (SRO), and making clear what the role of each of them is for the success of the project and for long-term sustainability.  
This paper illustrates and evaluates the evolution of partnerships and alliances explained above specifically for the case of the Napo Network, in the Peruvian Amazon rainforest, considering three stages: In stage 1 the alliances considered sufficient included universities, NGOs, and public governmental institutions; in stage 2, Mobile Network Operators (MNOs) and more diverse public institutions were added; in stage 3, Small Rural Operators (SRO) and other technological partners were also included in the consortium, and local organizations closer to communities where also included. a simple sustainability model is used to evaluate the relationship among those alliances and sustainability.