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RFC 7962 - Alternative Network Deployments: Taxonomy, Characterization, Technologies, and Architectures

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Internet Research Task Force (IRTF) J. Saldana, Ed. Request for Comments: 7962 University of Zaragoza Category: Informational A. Arcia-Moret ISSN: 2070-1721 University of Cambridge B. Braem iMinds E. Pietrosemoli The Abdus Salam ICTP A. Sathiaseelan University of Cambridge M. Zennaro The Abdus Salam ICTP August 2016
Alternative Network Deployments: Taxonomy, Characterization, Technologies, and Architectures Abstract This document presents a taxonomy of a set of "Alternative Network Deployments" that emerged in the last decade with the aim of bringing Internet connectivity to people or providing a local communication infrastructure to serve various complementary needs and objectives. They employ architectures and topologies different from those of mainstream networks and rely on alternative governance and business models. The document also surveys the technologies deployed in these networks, and their differing architectural characteristics, including a set of definitions and shared properties. The classification considers models such as Community Networks, Wireless Internet Service Providers (WISPs), networks owned by individuals but leased out to network operators who use them as a low-cost medium to reach the underserved population, networks that provide connectivity by sharing wireless resources of the users, and rural utility cooperatives. Saldana, et al. Informational [Page 1] RFC 7962 Alternative Network Deployments August 2016 Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Research Task Force (IRTF). The IRTF publishes the results of Internet-related research and development activities. These results might not be suitable for deployment. This RFC represents the consensus of the Global Access to the Internet for All Research Group of the Internet Research Task Force (IRTF). Documents approved for publication by the IRSG are not a candidate for any level of Internet Standard; see Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7962. Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Saldana, et al. Informational [Page 2] RFC 7962 Alternative Network Deployments August 2016 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Mainstream Networks . . . . . . . . . . . . . . . . . . . 5 1.2. Alternative Networks . . . . . . . . . . . . . . . . . . 5 2. Terms Used in This Document . . . . . . . . . . . . . . . . . 5 3. Scenarios Where Alternative Networks Are Deployed . . . . . . 7 3.1. Urban vs. Rural Areas . . . . . . . . . . . . . . . . . . 8 3.2. Topology Patterns Followed by Alternative Networks . . . 9 4. Classification Criteria . . . . . . . . . . . . . . . . . . . 10 4.1. Entity behind the Network . . . . . . . . . . . . . . . . 10 4.2. Purpose . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.3. Governance and Sustainability Model . . . . . . . . . . . 12 4.4. Technologies Employed . . . . . . . . . . . . . . . . . . 12 4.5. Typical Scenarios . . . . . . . . . . . . . . . . . . . . 13 5. Classification of Alternative Networks . . . . . . . . . . . 13 5.1. Community Networks . . . . . . . . . . . . . . . . . . . 14 5.2. Wireless Internet Service Providers (WISPs) . . . . . . . 16 5.3. Shared Infrastructure Model . . . . . . . . . . . . . . . 17 5.4. Crowdshared Approaches Led by the Users and Third-Party Stakeholders . . . . . . . . . . . . . . . . . . . . . . 19 5.5. Rural Utility Cooperatives . . . . . . . . . . . . . . . 21 5.6. Testbeds for Research Purposes . . . . . . . . . . . . . 22 6. Technologies Employed . . . . . . . . . . . . . . . . . . . . 22 6.1. Wired . . . . . . . . . . . . . . . . . . . . . . . . . . 22 6.2. Wireless . . . . . . . . . . . . . . . . . . . . . . . . 22 6.2.1. Media Access Control (MAC) Protocols for Wireless Links . . . . . . . . . . . . . . . . . . . . . . . . 23 6.2.1.1. 802.11 (Wi-Fi) . . . . . . . . . . . . . . . . . 23 6.2.1.2. Mobile Technologies . . . . . . . . . . . . . . . 24 6.2.1.3. Dynamic Spectrum . . . . . . . . . . . . . . . . 24 7. Upper Layers . . . . . . . . . . . . . . . . . . . . . . . . 26 7.1. Layer 3 . . . . . . . . . . . . . . . . . . . . . . . . . 26 7.1.1. IP Addressing . . . . . . . . . . . . . . . . . . . . 26 7.1.2. Routing Protocols . . . . . . . . . . . . . . . . . . 26 7.1.2.1. Traditional Routing Protocols . . . . . . . . . . 26 7.1.2.2. Mesh Routing Protocols . . . . . . . . . . . . . 27 7.2. Transport Layer . . . . . . . . . . . . . . . . . . . . . 27 7.2.1. Traffic Management When Sharing Network Resources . . 27 7.3. Services Provided . . . . . . . . . . . . . . . . . . . . 28 7.3.1. Use of VPNs . . . . . . . . . . . . . . . . . . . . . 29 7.3.2. Other Facilities . . . . . . . . . . . . . . . . . . 29 7.4. Security Considerations . . . . . . . . . . . . . . . . . 29 8. Informative References . . . . . . . . . . . . . . . . . . . 30 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 40 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42 Saldana, et al. Informational [Page 3] RFC 7962 Alternative Network Deployments August 2016 1. Introduction One of the aims of the Global Access to the Internet for All (GAIA) IRTF Research Group is "to document and share deployment experiences and research results to the wider community through scholarly publications, white papers, Informational and Experimental RFCs, etc." [GAIA]. In line with this objective, this document proposes a classification of "Alternative Network Deployments". This term includes a set of network access models that have emerged in the last decade with the aim of providing Internet connections, following topological, architectural, governance, and business models that differ from the so-called "mainstream" ones, where a company deploys the infrastructure connecting the users, who pay a subscription fee to be connected and make use of it. Several initiatives throughout the world have built these large-scale networks, using predominantly wireless technologies (including long distance links) due to the reduced cost of using unlicensed spectrum. Wired technologies such as fiber are also used in some of these networks. The classification considers several types of alternate deployments: Community Networks are self-organized networks wholly owned by the community; networks acting as Wireless Internet Service Providers (WISPs); networks owned by individuals but leased out to network operators who use such networks as a low-cost medium to reach the underserved population; networks that provide connectivity by sharing wireless resources of the users; and finally there are some rural utility cooperatives also connecting their members to the Internet. The emergence of these networks has been motivated by a variety of factors such as the lack of wired and cellular infrastructures in rural/remote areas [Pietrosemoli]. In some cases, Alternative Networks may provide more localized communication services as well as Internet backhaul support through peering agreements with mainstream network operators. In other cases, they are built as a complement or an alternative to commercial Internet access provided by mainstream network operators. The present document is intended to provide a broad overview of initiatives, technologies, and approaches employed in these networks, including some real examples. References describing each kind of network are also provided. Saldana, et al. Informational [Page 4] RFC 7962 Alternative Network Deployments August 2016 1.1. Mainstream Networks In this document, we will use the term "mainstream networks" to denote those networks sharing these characteristics: o Regarding scale, they are usually large networks spanning entire regions. o Top-down control of the network and centralized approach. o They require a substantial investment in infrastructure. o Users in mainstream networks do not participate in the network design, deployment, operation, governance, and maintenance. o Ownership of the network is never vested in the users themselves. 1.2. Alternative Networks The term "Alternative Network" proposed in this document refers to the networks that do not share the characteristics of "mainstream network deployments". Therefore, they may share some of the following characteristics: o Relatively small scale (i.e., not spanning entire regions). o Administration may not follow a centralized approach. o They may require a reduced investment in infrastructure, which may be shared by the users and commercial and non-commercial entities. o Users in Alternative Networks may participate in the network design, deployment, operation, and maintenance. o Ownership of the network is often vested in the users. 2. Terms Used in This Document Considering the role that the Internet currently plays in everyday life, this document touches on complex social, political, and economic issues. Some of the concepts and terminology used have been the subject of study of various disciplines outside the field of networking and are responsible for long debates whose resolution is out of the scope of this document. Saldana, et al. Informational [Page 5] RFC 7962 Alternative Network Deployments August 2016 o "Global north" and "global south". Although there is no consensus on the terms to be used when talking about the different development level of countries, we will employ the term "global south" to refer to nations with a relatively lower standard of living. This distinction is normally intended to reflect basic economic country conditions. In common practice, Japan in Asia, Canada and the United States in northern America, Australia and New Zealand in Oceania, and Europe are considered "developed" regions or areas [UN], so we will employ the term "global north" when talking about them. o The "Digital Divide". The following dimensions are considered to be meaningful when measuring the digital development state of a country: infrastructures (availability and affordability), the Information and Communications Technology (ICT) sector (human capital and technological industry), digital literacy, legal and regulatory framework, and content and services. A lack of digital development in one or more of these dimensions is what has been referred as the "Digital Divide" [Norris]. It should be noted that this "Divide" is not only present between different countries but between zones of the same country, despite its degree of development. o "Urban" and "rural" zones. There is no single definition of "rural" or "urban", as each country and various international organizations define these terms differently, mainly based on the number of inhabitants, the population density, and the distance between houses [UNStats]. For networking purposes, the primary distinction is likely the average distance between customers, typically measured by population density, as well as the distance to the nearest Internet point-of-presence, i.e., the distance to be covered by "middle mile" or backhaul connectivity. Some regions with low average population density may cluster almost all inhabitants into a small number of relatively dense small towns, for example, while residents may be dispersed more evenly in others. o Demand. In economics, it describes a consumer's desire and willingness to pay a price for a specific good or service. o Provision is the act of making an asset available for sale. In this document, we will mainly use it as the act of making a network service available to the inhabitants of a zone. o Underserved area. Area in which the telecommunication market permanently fails to provide the information and communications services demanded by the population. Saldana, et al. Informational [Page 6] RFC 7962 Alternative Network Deployments August 2016 o Free, open, and neutral networks. Their principles have been summarized this way [Baig]: * You have the freedom to use the network for any purpose as long as you do not harm the operation of the network itself, the rights of other users, or the principles of neutrality that allow contents and services to flow without deliberate interference. * You have the right to understand the network, to know its components, and to spread knowledge of its mechanisms and principles. * You have the right to offer services and content to the network on your own terms. * You have the right to join the network, and the responsibility to extend this set of rights to anyone according to these same terms. 3. Scenarios Where Alternative Networks Are Deployed Different studies have reported that as much as 60% of the people on the planet do not have Internet connectivity [Sprague] [InternetStats]. In addition, those unconnected are unevenly distributed: only 31% of the population in "global south" countries had access in 2014, against 80% in "global north" countries [WorldBank2016]. This is one of the reasons behind the inclusion of the objective to "significantly increase access to information and communications technology and strive to provide universal and affordable access to the Internet in least developed countries by 2020," as one of the targets in the Sustainable Development Goals (SDGs) [SDG], considered as a part of "Goal 9. Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation." For the purpose of this document, a distinction between "global north" and "global south" zones is made, highlighting the factors related to ICT, which can be quantified in terms of: o The availability of both national and international bandwidth, as well as equipment. o The difficulty in paying for the services and the devices required to access the ICTs. o The instability and/or lack of power supply. Saldana, et al. Informational [Page 7] RFC 7962 Alternative Network Deployments August 2016 o The scarcity of qualified staff. o The existence of a policy and regulatory framework that hinders the development of these models in favor of state monopolies or incumbents. In this context, the World Summit of the Information Society [WSIS] aimed at achieving "a people-centred, inclusive and development- oriented Information Society, where everyone can create, access, utilize and share information and knowledge. Therefore, enabling individuals, communities and people to achieve their full potential in promoting their sustainable development and improving their quality of life". It also called upon "governments, private sector, civil society and international organizations" to actively engage to work towards the bridging of the digital divide. Some Alternative Networks have been deployed in underserved areas, where citizens may be compelled to take a more active part in the design and implementation of ICT solutions. However, Alternative Networks (e.g., [Baig]) are also present in some "global north" countries, being built as an alternative to commercial ones managed by mainstream network operators. The consolidation of a number of mature Alternative Networks (e.g., Community Networks) sets a precedent for civil society members to become more active in the search for alternatives to provide themselves with affordable access. Furthermore, Alternative Networks could contribute to bridge the digital divide by increasing human capital and promoting the creation of localized content and services. 3.1. Urban vs. Rural Areas The differences presented in the previous section are not only present between countries, but within them too. This is especially the case for rural inhabitants, who represent approximately 55% of the world's population [IFAD2011], with 78% of them in "global south" countries [ITU2011]. According to the World Bank, adoption gaps "between rural and urban populations are falling for mobile phones but increasing for the internet" [WorldBank2016]. Although it is impossible to generalize among them, there exist some common features in rural areas that have prevented incumbent operators from providing access and that, at the same time, challenge the deployment of alternative infrastructures [Brewer] [Nungu] [Simo_c]. For example, a high network latency was reported in [Johnson_b], which could be in the order of seconds during some hours. Saldana, et al. Informational [Page 8] RFC 7962 Alternative Network Deployments August 2016 These challenges include: o Low per capita income, as the local economy is mainly based on subsistence agriculture, farming, and fishing. o Scarcity or absence of basic infrastructures, such as electricity, water, and access roads. o Low population density and distance (spatial or effective) between population clusters. o Underdeveloped social services, such as healthcare and education. o Lack of adequately educated and trained technicians, and high potential for those (few) trained to leave the community incentivized by better opportunities, higher salaries, or the possibility of starting their own companies [McMahon]. o High cost of Internet access [Mathee]. o Harsh environments leading to failure in electronic communication devices [Johnson_a], which reduces the reliability of the network. Some of these factors challenge the stability of Alternative Networks and the services they provide: scarcity of spectrum, scale, and heterogeneity of devices. However, the proliferation of Alternative Networks [Baig] together with the raising of low-cost, low- consumption, low-complexity off-the-shelf wireless devices have allowed and simplified the deployment and maintenance of alternative infrastructures in rural areas. 3.2. Topology Patterns Followed by Alternative Networks Alternative Networks, considered self-managed and self-sustained, follow different topology patterns [Vega_a]. Generally, these networks grow spontaneously and organically, that is, the network grows without specific planning and deployment strategy and the routing core of the network tends to fit a power law distribution. Moreover, these networks are composed of a high number of heterogeneous devices with the common objective of freely connecting and increasing the network coverage and the reliability. Although these characteristics increase the entropy (e.g., by increasing the number of routing protocols), they have resulted in an inexpensive solution to effectively increase the network size. One such example is Guifi.net [Vega_a], which has had an exponential growth rate in the number of operating nodes during the last decade. Saldana, et al. Informational [Page 9] RFC 7962 Alternative Network Deployments August 2016 Regularly, rural areas in these networks are connected through long- distance links and/or wireless mesh networks, which in turn convey the Internet connection to relevant organizations or institutions. In contrast, in urban areas, users tend to share and require mobile access. Since these areas are also likely to be covered by commercial ISPs, the provision of wireless access by virtual operators like [Fon] may constitute a way to extend the user capacity to the network. Other proposals like "Virtual Public Networks" [Sathiaseelan_a] can also extend the service. 4. Classification Criteria The classification of Alternative Network Deployments, presented in this document, is based on the following criteria: 4.1. Entity behind the Network The entity (or entities) or individuals behind an Alternative Network can be: o A community of users. o A public stakeholder. o A private company. o Supporters of a crowdshared approach. o A community that already owns the infrastructure and shares it with an operator, who, in turn, may also use it for backhauling purposes. o A research or academic entity. The above actors may play different roles in the design, financing, deployment, governance, and promotion of an Alternative Network. For example, each of the members of a Community Network maintains the ownership over the equipment they have contributed, whereas in others there is a single entity, e.g., a private company who owns the equipment, or at least a part of it. 4.2. Purpose Alternative Networks can be classified according to their purpose and the benefits they bring compared to mainstream solutions, regarding economic, technological, social, or political objectives. These benefits could be enjoyed mostly by the actors involved (e.g., lowering costs or gaining technical expertise) or by the local Saldana, et al. Informational [Page 10] RFC 7962 Alternative Network Deployments August 2016 community (e.g., Internet access in underserved areas) or by the society as a whole (e.g., network neutrality). The benefits provided by Alternative Networks include, but are not limited to: o Extending coverage to underserved areas (users and communities). o Providing affordable Internet access for all. o Reducing initial capital expenditures (for the network and the end user, or both). o Providing additional sources of capital (beyond the traditional carrier-based financing). o Reducing ongoing operational costs (such as backhaul or network administration). o Leveraging expertise and having a place for experimentation and teaching. o Reducing hurdles to adoption (e.g., digital literacy, literacy in general, and relevance). o Providing an alternative service in case of natural disasters and other extreme situations. o Community building, social cohesion, and quality of life improvement. o Experimentation with alternative governance and ownership models for treating network infrastructures as a commons. o Raising awareness of political debates around issues like network neutrality, knowledge sharing, access to resources, and more. Note that the different purposes of Alternative Networks can be more or less explicitly stated and they could also evolve over time based on the internal dynamics and external events. For example, the Red Hook WIFI network in Brooklyn [Redhook] started as a Community Network focusing more on local applications and community building [TidePools], but it became widely known when it played a key role as an alternative service available during the Sandy storm [Tech] [NYTimes]. Saldana, et al. Informational [Page 11] RFC 7962 Alternative Network Deployments August 2016 Moreover, especially for those networks with more open and horizontal governance models, the underlying motivations of those involved may be very diverse, ranging from altruistic ones related to the desire of free sharing of Internet connectivity and various forms of activism to personal benefits from the experience and expertise through the active participation in the deployment and management of a real and operational network. 4.3. Governance and Sustainability Model Different governance models are present in Alternative Networks. They may range from some open and horizontal models, with an active participation of the users (e.g., Community Networks) to a more centralized model, where a single authority (e.g., a company or a public stakeholder) plans and manages the network, even if it is (total or partially) owned by a community. Regarding sustainability, some networks grow "organically" as a result of the new users who join and extend the network, contributing their own hardware. In some other cases, the existence of previous infrastructure (owned by the community or the users) may lower the capital expenditures of an operator, who can therefore provide the service with better economic conditions. 4.4. Technologies Employed o Standard Wi-Fi. Many Alternative Networks are based on the standard IEEE 802.11 [IEEE.802.11] using the Distributed Coordination Function. o Wi-Fi-based Long Distance (WiLD) networks. These can work with either Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) or an alternative Time Division Multiple Access (TDMA) Media Access Control (MAC) [Simo_b]. o TDMA. It can be combined with a Wi-Fi protocol, in a non-standard way [airMAX]. This configuration allows each client to send and receive data using pre-designated timeslots. o 802.16-compliant (Worldwide Interoperability for Microwave Access (WiMax)) [IEEE.802.16] systems over non-licensed bands. o Dynamic Spectrum Solutions (e.g., based on the use of TV White Spaces). A set of television frequencies that can be utilized by secondary users in locations where they are unused, e.g., IEEE 802.11af [IEEE.802.11AF] or 802.22 [IEEE.802.22]. Saldana, et al. Informational [Page 12] RFC 7962 Alternative Network Deployments August 2016 o Satellite solutions can also be employed to give coverage to wide areas, as proposed in the RIFE project (https://rife-project.eu/). o Low-cost optical fiber systems are also used to connect households in different places. 4.5. Typical Scenarios The scenarios where Alternative Networks are usually deployed can be classified as: o Urban/rural areas. o "Global north" / "global south" countries. 5. Classification of Alternative Networks This section classifies Alternative Networks according to the criteria explained previously. Each of them has different incentive structures, maybe common technological challenges, but most importantly interesting usage challenges that feed into the incentives as well as the technological challenges. At the beginning of each subsection, a table is presented including a classification of each network according to the criteria listed in the "Classification Criteria" subsection. Real examples of each kind of Alternative Network are cited. Saldana, et al. Informational [Page 13] RFC 7962 Alternative Network Deployments August 2016 5.1. Community Networks +----------------+--------------------------------------------------+ | Entity behind | community | | the network | | +----------------+--------------------------------------------------+ | Purpose | all the goals listed in Section 4.2 may be | | | present | +----------------+--------------------------------------------------+ | Governance and | participatory administration model: non- | | sustainability | centralized and open building and maintenance; | | model | users may contribute their own hardware | +----------------+--------------------------------------------------+ | Technologies | Wi-Fi [IEEE.802.11] (standard and non-standard | | employed | versions) and optical fiber | +----------------+--------------------------------------------------+ | Typical | urban and rural | | scenarios | | +----------------+--------------------------------------------------+ Table 1: Characteristics Summary for Community Networks Community Networks are non-centralized, self-managed networks sharing these characteristics: o They start and grow organically, and they are open to participation from everyone, sharing an open participation agreement. Community members directly contribute active (not just passive) network infrastructure. The network grows as new hosts and links are added. o Knowledge about building and maintaining the network and ownership of the network itself is non-centralized and open. Different degrees of centralization can be found in Community Networks. In some of them, a shared platform (e.g., a website) may exist where minimum coordination is performed. Community members with the right permissions have an obvious and direct form of organizational control over the overall organization of the network (e.g., IP addresses, routing, etc.) in their community (not just their own participation in the network). o The network can serve as a backhaul for providing a whole range of services and applications, from completely free to even commercial services. Saldana, et al. Informational [Page 14] RFC 7962 Alternative Network Deployments August 2016 Hardware and software used in Community Networks can be very diverse and customized, even inside one network. A Community Network can have both wired and wireless links. Multiple routing protocols or network topology management systems may coexist in the network. These networks grow organically, since they are formed by the aggregation of nodes belonging to different users. A minimal governance infrastructure is required in order to coordinate IP addressing, routing, etc. Several examples of Community Networks are described in [Braem]. A technological analysis of a Community Network is presented in [Vega_b], which focuses on technological network diversity, topology characteristics, the evolution of the network over time, robustness and reliability, and networking service availability. These networks follow a participatory administration model, which has been shown to be effective in connecting geographically dispersed people, thus enhancing and extending digital Internet rights. Users adding new infrastructure (i.e., extensibility) can be used to formulate another definition: A Community Network is a network in which any participant in the system may add link segments to the network in such a way that the new segments can support multiple nodes and adopt the same overall characteristics as those of the joined network, including the capacity to further extend the network. Once these link segments are joined to the network, there is no longer a meaningful distinction between the previous and the new extent of the network. The term "participant" refers to an individual, who may become the user, provider, and manager of the network at the same time. In Community Networks, profit can only be made by offering services and not simply by supplying the infrastructure, because the infrastructure is neutral, free, and open (mainstream Internet Service Providers base their business on the control of the infrastructure). In Community Networks, everybody usually keeps the ownership of what he/she has contributed or leaves the stewardship of the equipment to the network as a whole (the commons), even loosing track of the ownership of a particular equipment itself, in favor of the community. The majority of Community Networks comply with the definition of Free Network, included in Section 2. Saldana, et al. Informational [Page 15] RFC 7962 Alternative Network Deployments August 2016 5.2. Wireless Internet Service Providers (WISPs) +----------------+--------------------------------------------------+ | Entity behind | company | | the network | | +----------------+--------------------------------------------------+ | Purpose | to serve underserved areas; to reduce capital | | | expenditures in Internet access; and to provide | | | additional sources of capital | +----------------+--------------------------------------------------+ | Governance and | operated by a company that provides the | | sustainability | equipment; centralized administration | | model | | +----------------+--------------------------------------------------+ | Technologies | wireless, e.g., [IEEE.802.11] and [IEEE.802.16] | | employed | and unlicensed frequencies | +----------------+--------------------------------------------------+ | Typical | rural (urban deployments also exist) | | scenarios | | +----------------+--------------------------------------------------+ Table 2: Characteristics Summary for WISPs WISPs are commercially operated wireless Internet networks that provide Internet and/or Voice over Internet (VoIP) services. They are most common in areas not covered by mainstream telecommunications companies or ISPs. WISPs mostly use wireless point-to-multipoint links using unlicensed spectrum but often must resort to licensed frequencies. Use of licensed frequencies is common in regions where unlicensed spectrum is either perceived to be crowded or too unreliable to offer commercial services, or where unlicensed spectrum faces regulatory barriers impeding its use. Most WISPs are operated by local companies responding to a perceived market gap. There is a small but growing number of WISPs, such as [Airjaldi] in India, that have expanded from local service into multiple locations. Since 2006, the deployment of cloud-managed WISPs has been possible with hardware from companies such as [Meraki] and later [OpenMesh] and others. Until recently, however, most of these services have been aimed at "global north" markets. In 2014, a cloud-managed WISP service aimed at "global south" markets was launched [Everylayer]. Saldana, et al. Informational [Page 16] RFC 7962 Alternative Network Deployments August 2016 5.3. Shared Infrastructure Model +----------------+--------------------------------------------------+ | Entity behind | shared: companies and users | | the network | | +----------------+--------------------------------------------------+ | Purpose | to eliminate a capital expenditures barrier (to | | | operators); lower the operating expenses | | | (supported by the community); and extend | | | coverage to underserved areas | +----------------+--------------------------------------------------+ | Governance and | the community rents the existing infrastructure | | sustainability | to an operator | | model | | +----------------+--------------------------------------------------+ | Technologies | wireless in non-licensed bands, mobile | | employed | femtocells, WiLD networks [WiLD], and/or low- | | | cost fiber | +----------------+--------------------------------------------------+ | Typical | rural areas, and more particularly rural areas | | scenarios | in "global south" regions | +----------------+--------------------------------------------------+ Table 3: Characteristics Summary for Shared Infrastructure In mainstream networks, the operator usually owns the telecommunications infrastructure required for the service or sometimes rents infrastructure to/from other companies. The problem arises in large areas with low population density, in which neither the operator nor the other companies have deployed infrastructure and such deployments are not likely to happen due to the low potential return on investment. When users already own deployed infrastructure, either individually or as a community, sharing that infrastructure with an operator can benefit both parties and is a solution that has been deployed in some areas. For the operator, this provides a significant reduction in the initial investment needed to provide services in small rural localities because capital expenditure is only associated with the access network. Renting capacity in the users' network for backhauling only requires an increment in the operating expenditure. This approach also benefits the users in two ways: they obtain improved access to telecommunications services that would not be accessible otherwise, and they can derive some income from the operator that helps to offset the network's operating costs, particularly for network maintenance. Saldana, et al. Informational [Page 17] RFC 7962 Alternative Network Deployments August 2016 One clear example of the potential of the "shared infrastructure model" nowadays is the deployment of 3G services in rural areas in which there is a broadband rural Community Network. Since the inception of femtocells (small, low-power cellular base stations), there are complete technical solutions for low-cost 3G coverage using the Internet as a backhaul. If a user or community of users has an IP network connected to the Internet with some excess capacity, placing a femtocell in the user premises benefits both the user and the operator, as the user obtains better coverage and the operator does not have to support the cost of the backhaul infrastructure. Although this paradigm was conceived for improved indoor coverage, the solution is feasible for 3G coverage in underserved rural areas with low population density (i.e., villages), where the number of simultaneous users and the servicing area are small enough to use low-cost femtocells. Also, the amount of traffic produced by these cells can be easily transported by most community broadband rural networks. Some real examples can be referenced in the TUCAN3G project, which deployed demonstrator networks in two regions in the Amazon forest in Peru [Simo_d]. In these networks [Simo_a], the operator and several rural communities cooperated to provide services through rural networks built up with WiLD links [WiLD]. In these cases, the networks belonged to the public health authorities and were deployed with funds that came from international cooperation for telemedicine purposes. Publications that justify the feasibility of this approach can also be found on that website. Saldana, et al. Informational [Page 18] RFC 7962 Alternative Network Deployments August 2016 5.4. Crowdshared Approaches Led by the Users and Third-Party Stakeholders +----------------+--------------------------------------------------+ | Entity behind | community, public stakeholders, private | | the network | companies, and supporters of a crowdshared | | | approach | +----------------+--------------------------------------------------+ | Purpose | sharing connectivity and resources | +----------------+--------------------------------------------------+ | Governance and | users share their capacity, coordinated by a | | sustainability | Virtual Network Operator (VNO); different models | | model | may exist, depending on the nature of the VNO | +----------------+--------------------------------------------------+ | Technologies | Wi-Fi [IEEE.802.11] | | employed | | +----------------+--------------------------------------------------+ | Typical | urban and rural | | scenarios | | +----------------+--------------------------------------------------+ Table 4: Characteristics Summary for Crowdshared Approaches These networks can be defined as a set of nodes whose owners share common interests (e.g., sharing connectivity; resources; and peripherals) regardless of their physical location. They conform to the following approach: the home router creates two wireless networks -- one of them is normally used by the owner, and the other one is public. A small fraction of the bandwidth is allocated to the public network to be employed by any user of the service in the immediate area. Some examples are described in [PAWS] and [Sathiaseelan_c]. Other examples are found in the networks created and managed by city councils (e.g., [Heer]). The "openwireless movement" (https://openwireless.org/) also promotes the sharing of private wireless networks. Some companies [Fon] also promote the use of Wi-Fi routers with dual access: a Wi-Fi network for the user and a shared one. Adequate Authentication, Authorization, and Accounting (AAA) policies are implemented, so people can join the network in different ways: they can buy a router, so they can share their connection and in turn, they get access to all the routers associated with the community. Some users can even get some revenue every time another user connects to their Wi-Fi Access Point. Users that are not part of the community can buy passes in order to use the network. Some mainstream telecommunications operators collaborate with these Saldana, et al. Informational [Page 19] RFC 7962 Alternative Network Deployments August 2016 communities by including the functionality required to create the two access networks in their routers. Some of these efforts are surveyed in [Shi]. The elements involved in a crowdshared network are summarized below: o Interest: A parameter capable of providing a measure (cost) of the attractiveness of a node in a specific location, at a specific instance in time. o Resources: A physical or virtual element of a global system. For instance, bandwidth; energy; data; and devices. o The owner: End users who sign up for the service and share their network capacity. As a counterpart, they can access another owner's home network capacity for free. The owner can be an end user or an entity (e.g., operator; virtual mobile network operator; or municipality) that is to be made responsible for any actions concerning his/her device. o The user: A legal entity or an individual using or requesting a publicly available electronic communications service for private or business purposes, without necessarily having subscribed to such service. o The VNO: An entity that acts in some aspects as a network coordinator. It may provide services such as initial authentication or registration and, eventually, trust relationship storage. A VNO is not an ISP given that it does not provide Internet access (e.g., infrastructure or naming). A VNO is not an Application Service Provider (ASP) either since it does not provide user services. VNOs may also be stakeholders with socio- environmental objectives. They can be local governments, grassroots user communities, charities, or even content operators, smart grid operators, etc. They are the ones who actually run the service. o Network operators: They have a financial incentive to lease out unused capacity [Sathiaseelan_b] at a lower cost to the VNOs. VNOs pay the sharers and the network operators, thus creating an incentive structure for all the actors: the end users get money for sharing their network, and the network operators are paid by the VNOs, who in turn accomplish their socio-environmental role. Saldana, et al. Informational [Page 20] RFC 7962 Alternative Network Deployments August 2016 5.5. Rural Utility Cooperatives +---------------------+---------------------------------------------+ | Entity behind the | rural utility cooperative | | network | | +---------------------+---------------------------------------------+ | Purpose | to serve underserved areas and to reduce | | | capital expenditures in Internet access | +---------------------+---------------------------------------------+ | Governance and | the cooperative partners with an ISP who | | sustainability | manages the network | | model | | +---------------------+---------------------------------------------+ | Technologies | wired (fiber) and wireless | | employed | | +---------------------+---------------------------------------------+ | Typical scenarios | rural | +---------------------+---------------------------------------------+ Table 5: Characteristics Summary for Rural Utility Cooperatives A utility cooperative is a type of cooperative that delivers a public utility to its members. For example, in the United States, rural electric cooperatives have provided electric service starting in the 1930s, especially in areas where investor-owned utility would not provide service, believing there would be insufficient revenue to justify the capital expenditures required. Similarly, in many regions with low population density, traditional Internet Service Providers such as telephone companies or cable TV companies are either not providing service at all or only offering low-speed DSL service. Some rural electric cooperatives started installing fiber optic lines to run their smart grid applications, but they found they could provide fiber-based broadband to their members at little additional cost [Cash]. In some of these cases, rural electric cooperatives have partnered with local ISPs to provide Internet connection to their members [Carlson]. More information about these utilities and their management can be found in [NewMexico] and [Mitchell]. Saldana, et al. Informational [Page 21] RFC 7962 Alternative Network Deployments August 2016 5.6. Testbeds for Research Purposes +------------------+------------------------------------------------+ | Entity behind | research/academic entity | | the network | | +------------------+------------------------------------------------+ | Purpose | research | +------------------+------------------------------------------------+ | Governance and | the management is initially coordinated by the | | sustainability | research entity, but it may end up in a | | model | different model | +------------------+------------------------------------------------+ | Technologies | wired and wireless | | employed | | +------------------+------------------------------------------------+ | Typical | urban and rural | | scenarios | | +------------------+------------------------------------------------+ Table 6: Characteristics Summary for Testbeds In some cases, the initiative to start the network is not from the community but from a research entity (e.g., a university), with the aim of using it for research purposes [Samanta] [Bernardi]. The administration of these networks may start being centralized in most cases (administered by the academic entity) and may end up in a non-centralized model in which other local stakeholders assume part of the network administration (for example, see [Rey]). 6. Technologies Employed 6.1. Wired In many ("global north" or "global south") countries, it may happen that national service providers decline to provide connectivity to tiny and isolated villages. So in some cases, the villagers have created their own optical fiber networks. This is the case in Lowenstedt, Germany [Lowenstedt] or in some parts of Guifi.net [Cerda-Alabern]. 6.2. Wireless The vast majority of Alternative Network Deployments are based on different wireless technologies [WNDW]. Below we summarize the options and trends when using these features in Alternative Networks. Saldana, et al. Informational [Page 22] RFC 7962 Alternative Network Deployments August 2016 6.2.1. Media Access Control (MAC) Protocols for Wireless Links Different protocols for MAC, which also include physical layer (PHY) recommendations, are widely used in Alternative Network Deployments. Wireless standards ensure interoperability and usability to those who design, deploy, and manage wireless networks. In addition, they then ensure the low cost of equipment due to economies of scale and mass production. The standards used in the vast majority of Alternative Networks come from the IEEE Standard Association's IEEE 802 Working Group. Standards developed by other international entities can also be used, such as, e.g., the European Telecommunications Standards Institute (ETSI). 6.2.1.1. 802.11 (Wi-Fi) The standard we are most interested in is 802.11 a/b/g/n/ac, as it defines the protocol for Wireless LAN. It is also known as "Wi-Fi". The original release (a/b) was issued in 1999 and allowed for rates up to 54 Mbit/s. The latest release (802.11ac) approved in 2013 reaches up to 866.7 Mbit/s. In 2012, the IEEE issued an 802.11 standard that consolidated all the previous amendments [IEEE.802.11]. The document is freely downloadable from the IEEE Standards Association [IEEE]. The MAC protocol in 802.11 is called CSMA/CA and was designed for short distances; the transmitter expects the reception of an acknowledgment for each transmitted unicast packet and if a certain waiting time is exceeded, the packet is retransmitted. This behavior makes necessary the adaptation of several MAC parameters when 802.11 is used in long links [Simo_b]. Even with this adaptation, distance has a significant negative impact on performance. For this reason, many vendors implement alternative medium access techniques that are offered alongside the standard CSMA/CA in their outdoor 802.11 products. These alternative proprietary MAC protocols usually employ some type of TDMA. Low-cost equipment using these techniques can offer high throughput at distances above 100 kilometers. Different specifications of 802.11 operate in different frequency bands. 802.11b/g/n operates in 2.4 GHz, but 802.11a/n/ac operates in 5 GHz. This fact is used in some Community Networks in order to separate ordinary and "backbone" nodes: o Typical routers running mesh firmware in homes, offices, and public spaces operate at 2.4 GHz. Saldana, et al. Informational [Page 23] RFC 7962 Alternative Network Deployments August 2016 o Special routers running mesh firmware as well but broadcasting and receiving on the 5 GHz band are used in point-to-point connections only. They are helpful to create a "backbone" on the network that can both connect neighborhoods to one another when reasonable connections with 2.4 GHz nodes are not possible, and they ensure that users of 2.4 GHz nodes are within a few hops to strong and stable connections to the rest of the network. 6.2.1.2. Mobile Technologies Global System for Mobile Communications (GSM), from ETSI, has also been used in Alternative Networks as a Layer 2 option, as explained in [Mexican], [Village], and [Heimerl]. Open source GSM code projects such as OpenBTS (http://openbts.org) or OpenBSC (http://openbsc.osmocom.org/trac/) have created an ecosystem with the participation of several companies such as, e.g., [Rangenetworks], [Endaga], and [YateBTS]. This enables deployments of voice, SMS, and Internet services over Alternative Networks with an IP-based backhaul. Internet navigation is usually restricted to relatively low bit rates (see, e.g., [Osmocom]). However, leveraging on the evolution of Third Generation Partnership Project (3GPP) standards, a trend can be observed towards the integration of 4G [Spectrum] [YateBTS] or 5G [Openair] functionalities, with significant increase of achievable bit rates. Depending on factors such as the allocated frequency band, the adoption of licensed spectrum can have advantages over the eventually higher frequencies used for Wi-Fi, in terms of signal propagation and, consequently, coverage. Other factors favorable to 3GPP technologies, especially GSM, are the low cost and energy consumption of handsets, which facilitate its use by low-income communities. 6.2.1.3. Dynamic Spectrum Some Alternative Networks make use of TV White Spaces [Lysko] -- a set of UHF and VHF television frequencies that can be utilized by secondary users in locations where they are unused by licensed primary users such as television broadcasters. Equipment that makes use of TV White Spaces is required to detect the presence of existing unused TV channels by means of a spectrum database and/or spectrum sensing in order to ensure that no harmful interference is caused to primary users. In order to smartly allocate interference-free channels to the devices, cognitive radios are used that are able to modify their frequency, power, and modulation techniques to meet the strict operating conditions required for secondary users. Saldana, et al. Informational [Page 24] RFC 7962 Alternative Network Deployments August 2016 The use of the term "White Spaces" is often used to describe "TV White Spaces" as the VHF and UHF television frequencies were the first to be exploited on a secondary use basis. There are two dominant standards for TV White Space communication: (i) the 802.11af standard [IEEE.802.11AF] -- an adaptation of the 802.11 standard for TV White Space bands -- and (ii) the IEEE 802.22 standard [IEEE.802.22] for long-range rural communication. 6.2.1.3.1. 802.11af 802.11af [IEEE.802.11AF] is a modified version of the 802.11 standard operating in TV White Space bands using cognitive radios to avoid interference with primary users. The standard is often referred to as "White-Fi" or "Super Wi-Fi" and was approved in February 2014. 802.11af contains much of the advances of all the 802.11 standards including recent advances in 802.11ac such as up to four bonded channels, four spatial streams, and very high-rate 256 QAM (Quadrature Amplitude Modulation) but with improved in-building penetration and outdoor coverage. The maximum data rate achievable is 426.7 Mbit/s for countries with 6/7 MHz channels and 568.9 Mbit/s for countries with 8 MHz channels. Coverage is typically limited to 1 km although longer range at lower throughput and using high gain antennas will be possible. Devices are designated as enabling stations (Access Points) or dependent stations (clients). Enabling stations are authorized to control the operation of a dependent station and securely access a geolocation database. Once the enabling station has received a list of available White Space channels, it can announce a chosen channel to the dependent stations for them to communicate with the enabling station. 802.11af also makes use of a registered location server -- a local database that organizes the geographic location and operating parameters of all enabling stations. 6.2.1.3.2. 802.22 802.22 [IEEE.802.22] is a standard developed specifically for long- range rural communications in TV White Space frequencies and was first approved in July 2011. The standard is similar to the 802.16 (WiMax) [IEEE.802.16] standard with an added cognitive radio ability. The maximum throughput of 802.22 is 22.6 Mbit/s for a single 8 MHz channel using 64-QAM modulation. The achievable range using the default MAC scheme is 30 km; however, 100 km is possible with special scheduling techniques. The MAC of 802.22 is specifically customized for long distances -- for example, slots in a frame destined for more distant Consumer Premises Equipment (CPE) are sent before slots destined for nearby CPEs. Saldana, et al. Informational [Page 25] RFC 7962 Alternative Network Deployments August 2016 Base stations are required to have a Global Positioning System (GPS) and a connection to the Internet in order to query a geolocation spectrum database. Once the base station receives the allowed TV channels, it communicates a preferred operating TV White Space channel with the CPE devices. The standard also includes a coexistence mechanism that uses beacons to make other 802.22 base stations aware of the presence of a base station that is not part of the same network. 7. Upper Layers 7.1. Layer 3 7.1.1. IP Addressing Most Community Networks use private IPv4 address ranges, as defined by [RFC1918]. The motivation for this was the lower cost and the simplified IP allocation because of the large available address ranges. Most known Alternative Networks started in or around the year 2000. IPv6 was fully specified by then, but almost all Alternative Networks still use IPv4. A survey [Avonts] indicated that IPv6 rollout presented a challenge to Community Networks. However, some of them have already adopted it, such as ninux.org. 7.1.2. Routing Protocols As stated in previous sections, Alternative Networks are composed of possibly different Layer 2 devices, resulting in a mesh of nodes. A connection between different nodes is not guaranteed, and the link stability can vary strongly over time. To tackle this, some Alternative Networks use mesh routing protocols for Mobile Ad Hoc Networks (MANETs), while other ones use more traditional routing protocols. Some networks operate multiple routing protocols in parallel. For example, they may use a mesh protocol inside different islands and rely on traditional routing protocols to connect these islands. 7.1.2.1. Traditional Routing Protocols The Border Gateway Protocol (BGP), as defined by [RFC4271], is used by a number of Community Networks because of its well-studied behavior and scalability. For similar reasons, smaller networks opt to run the Open Shortest Path First (OSPF) protocol, as defined by [RFC2328]. Saldana, et al. Informational [Page 26] RFC 7962 Alternative Network Deployments August 2016 7.1.2.2. Mesh Routing Protocols A large number of Alternative Networks use customized versions of the Optimized Link State Routing (OLSR) Protocol [RFC3626]. The open source project [OLSR] has extended the protocol with the Expected Transmission Count (ETX) metric [Couto] and other features for its use in Alternative Networks, especially wireless ones. A new version of the protocol, named OLSRv2 [RFC7181], is becoming used in some Community Networks [Barz]. Better Approach To Mobile Ad Hoc Networking (B.A.T.M.A.N.) Advanced [Seither] is a Layer 2 routing protocol, which creates a bridged network and allows seamless roaming of clients between wireless nodes. Some networks also run the BatMan-eXperimental Version 6 (BMX6) protocol [Neumann_a], which is based on IPv6 and tries to exploit the social structure of Alternative Networks. Babel [RFC6126] is a Layer 3 loop-avoiding distance-vector routing protocol that is robust and efficient both in wired and wireless mesh networks. In [Neumann_b], a study of three proactive mesh routing protocols (BMX6, OLSR, and Babel) is presented, in terms of scalability, performance, and stability. 7.2. Transport Layer 7.2.1. Traffic Management When Sharing Network Resources When network resources are shared (as, e.g., in the networks explained in Section 5.4), special care has to be taken with the management of the traffic at upper layers. From a crowdshared perspective, and considering just regular TCP connections during the critical sharing time, the Access Point offering the service is likely to be the bottleneck of the connection. This is the main concern of sharers, having several implications. In some cases, an adequate Active Queue Management (AQM) mechanism that implements a Less-than-Best-Effort (LBE) [RFC6297] policy for the user is used to protect the sharer. Achieving LBE behavior requires the appropriate tuning of well-known mechanisms such as Explicit Congestion Notification (ECN) [RFC3168], Random Early Detection (RED) [RFC7567], or other more recent AQM mechanisms that aid low latency such as Controlled Delay (CoDel) [CoDel] and Proportional Integral controller Enhanced (PIE) [PIE] design. Saldana, et al. Informational [Page 27] RFC 7962 Alternative Network Deployments August 2016 7.3. Services Provided This section provides an overview of the services provided by the network. Many Alternative Networks can be considered Autonomous Systems, being (or aspiring to be) a part of the Internet. The services provided can include, but are not limited to: o Web browsing. o Email. o Remote desktop (e.g., using my home computer and my Internet connection when I am away). o FTP file sharing (e.g., distribution of software and media). o VoIP (e.g., with SIP). o Peer-to-Peer (P2P) file sharing. o Public video cameras. o DNS. o Online game servers. o Jabber instant messaging. o Weather stations. o Network monitoring. o Videoconferencing/streaming. o Radio streaming. o Message/bulletin board. o Local cloud storage services. Due to bandwidth limitations, some services (file sharing, VoIP, etc.) may not be allowed in some Alternative Networks. In some of these cases, a number of federated proxies provide web-browsing service for the users. Saldana, et al. Informational [Page 28] RFC 7962 Alternative Network Deployments August 2016 Some specialized services have been specifically developed for Alternative Networks: o Inter-network peering/VPNs (e.g., https://wiki.freifunk.net/IC-VPN). o Community-oriented portals (e.g., http://tidepools.co/). o Network monitoring/deployment/maintenance platforms. o VoIP sharing between networks, allowing cheap calls between countries. o Sensor networks and citizen science built by adding sensors to devices. o Community radio/TV stations. Other services (e.g., local wikis as used in community portals; see https://localwiki.org) can also provide useful information when supplied through an Alternative Network, although they were not specifically created for them. 7.3.1. Use of VPNs Some "micro-ISPs" may use the network as a backhaul for providing Internet access, setting up VPNs from the client to a machine with Internet access. Many Community Networks also use VPNs to connect multiple disjoint parts of their networks together. In some others, every node establishes a VPN tunnel as well. 7.3.2. Other Facilities Other facilities, such as NTP or Internet Relay Chat (IRC) servers may also be present in Alternative Networks. 7.4. Security Considerations No security issues have been identified for this document. Saldana, et al. Informational [Page 29] RFC 7962 Alternative Network Deployments August 2016 8. Informative References [Airjaldi] AirJaldi Networks, "Airjaldi Service", 2015, <https://airjaldi.com/>. [airMAX] Ubiquiti Networks, Inc., "airMAX", 2016, <https://www.ubnt.com/broadband/>. [Avonts] Avonts, J., Braem, B., and C. Blondia, "A Questionnaire based Examination of Community Networks", IEEE 9th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), pp. 8-15, DOI 10.1109/WiMOB.2013.6673333, October 2013. [Baig] Baig, R., Roca, R., Freitag, F., and L. Navarro, "guifi.net, a crowdsourced network infrastructure held in common", Computer Networks, Vol. 90, Issue C, pp. 150-165, DOI 10.1016/j.comnet.2015.07.009, October 2015. [Barz] Barz, C., Fuchs, C., Kirchhoff, J., Niewiejska, J., and H. Rogge, "OLSRv2 for Community Networks", Computer Networks, Vol. 93, Issue P2, pp. 324-341, December 2015, <http://dx.doi.org/10.1016/j.comnet.2015.09.022>. [Bernardi] Bernardi, B., Buneman, P., and M. Marina, "Tegola Tiered Mesh Network Testbed in Rural Scotland", Proceedings of the 2008 ACM workshop on Wireless networks and systems for developing regions, pp. 9-16, DOI 10.1145/1410064.1410067, 2008. [Braem] Braem, B., Baig Vinas, R., Kaplan, A., Neumann, A., Vilata i Balaguer, I., Tatum, B., Matson, M., Blondia, C., Barz, C., Rogge, H., Freitag, F., Navarro, L., Bonicioli, J., Papathanasiou, S., and P. Escrich, "A Case for Research with and on Community Networks", ACM SIGCOMM Computer Communication Review, Vol. 43, Issue 3, pp. 68-73, DOI 10.1145/2500098.2500108, July 2013. [Brewer] Brewer, E., Demmer, M., Du, B., Ho, M., Kam, M., Nedevschi, S., Pal, J., Patra, R., Surana, S., and K. Fall, "The Case for Technology in Developing Regions", IEEE Computer Society, Vol. 38, Issue 6, pp. 25-38, DOI 10.1109/MC.2005.204, 2005. Saldana, et al. Informational [Page 30] RFC 7962 Alternative Network Deployments August 2016 [Carlson] Carlson, S. and C. Mitchell, "RS Fiber: Fertile Fields for New Rural Internet Cooperative", Institute for Local Self- Reliance and Next Century Cities, April 2016, <https://ilsr.org/wp-content/uploads/downloads/2016/04/ rs-fiber-report-2016.pdf>. [Cash] Cash, C., "CO-MO'S D.I.Y. Model for Building Broadband", National Rural Electric Cooperative Association (NRECA), November 2015, <http://remagazine.coop/co-mo-broadband/>. [Cerda-Alabern] Cerda-Alabern, L., "On the topology characterization of Guifi.net", Proceedings of the IEEE 8th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), pp. 389-396, DOI 10.1109/WiMOB.2012.6379103, October 2012. [CoDel] Nichols, K., Jacobson, V., McGregor, A., and J. Iyengar, "Controlled Delay Active Queue Management", Work in Progress, draft-ietf-aqm-codel-04, June 2016. [Couto] De Couto, D., Aguayo, D., Bicket, J., and R. Morris, "A high-throughput path metric for multi-hop wireless routing", Wireless Networks, Vol. 11, Issue 4, pp. 419-434, DOI 10.1007/s11276-005-1766-z, July 2005. [Endaga] Alleven, M., "Endaga raises $1.2M to help it bring cellular to remote villages", FierceWireless Tech News, December 2014, <http://www.fiercewireless.com/tech/story/ endaga-raises-12m-help-it-bring-cellular-remote- villages/2014-12-03>. [Everylayer] Everylayer, Inc. (formerly Volo Broadband), "Everylayer", 2015, <http://www.everylayer.com/>. [Fon] Fon, "Fon is the Global WiFi Network", 2014, <https://corp.fon.com/en>. [GAIA] Internet Research Task Force, "Charter: Global Access to the Internet for All Research Group (GAIA)", 2016, <https://irtf.org/gaia>. Saldana, et al. Informational [Page 31] RFC 7962 Alternative Network Deployments August 2016 [Heer] Heer, T., Hummen, R., Viol, N., Wirtz, H., Gotz, S., and K. Wehrle, "Collaborative municipal Wi-Fi networks- challenges and opportunities", 8th IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOM Workshops), pp. 588-593, DOI 10.1109/PERCOMW.2010.5470505, 2010. [Heimerl] Heimerl, K., Shaddi, H., Ali, K., Brewer, E., and T. Parikh, "Local, sustainable, small-scale cellular networks", In ICTD 2013, Cape Town, South Africa, DOI 10.1145/2516604.2516616, 2013. [IEEE] Institute of Electrical and Electronics Engineers (IEEE), "IEEE Standards Association", <https://standards.ieee.org/>. [IEEE.802.11] IEEE, "IEEE Standard for Information technology-- Telecommunications and information exchange between systems Local and metropolitan area networks--Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications", IEEE 802.11-2012, DOI 10.1109/ieeestd.2012.6178212, April 2012, <http://standards.ieee.org/getieee802/ download/802.11-2012.pdf>. [IEEE.802.11AF] IEEE, "IEEE Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications - Amendment 5: Television White Spaces (TVWS) Operation", IEEE 802.11af-2013, DOI 10.1109/ieeestd.2014.6744566, February 2014, <http://standards.ieee.org/getieee802/ download/802.11af-2013.pdf>. [IEEE.802.16] IEEE, "IEEE Standard for Information technology - Telecommunications and information exchange between systems - Broadband wireless metropolitan area networks (MANs) - IEEE Standard for Air Interface for Broadband Wireless Access Systems", IEEE 802.16-2012, DOI 10.1109/ieeestd.2012.6272299, August 2012, <http://standards.ieee.org/getieee802/ download/802.16-2012.pdf>. Saldana, et al. Informational [Page 32] RFC 7962 Alternative Network Deployments August 2016 [IEEE.802.22] IEEE, "IEEE Standard for Information technology-- Local and metropolitan area networks-- Specific requirements-- Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Policies and procedures for operation in the TV Bands", IEEE 802.22-2011, DOI 10.1109/ieeestd.2011.5951707, July 2011, <http://ieeexplore.ieee.org/servlet/ opac?punumber=5951705>. [IFAD2011] International Fund for Agricultural Development (IFAD), "Rural Poverty Report 2011", ISBN 978-92-9072-200-7, 2011. [InternetStats] Internet World Stats, "World Internet Users and 2015 Population Stats", <http://www.internetworldstats.com/stats.htm>. [ITU2011] International Telecommunication Union, "World Telecommunication/ICT Indicators Database - 2011", <http://www.itu.int/en/ITU-D/Statistics/Pages/ publications/wtid.aspx>. [Johnson_a] Johnson, D. and K. Roux, "Building Rural Wireless Networks: Lessons Learnt and Future Directions", In Proceedings of the ACM workshop on Wireless networks and systems for developing regions, pp. 17-22, DOI 10.1145/1410064.1410068, 2008. [Johnson_b] Johnson, D., Pejovic, V., Belding, E., and G. van Stam, "Traffic Characterization and Internet Usage in Rural Africa", In Proceedings of the 20th International Conference Companion on World Wide Web, pp. 493-502, DOI 10.1145/1963192.1963363, 2011. [Lowenstedt] Huggler, J., "German villagers set up their own broadband network", June 2014, <http://www.telegraph.co.uk/news/worldnews/europe/ germany/10871150/ German-villagers-set-up-their-own-broadband-network.html>. Saldana, et al. Informational [Page 33] RFC 7962 Alternative Network Deployments August 2016 [Lysko] Lysko, A., Masonta, M., Mofolo, M., Mfupe, L., Montsi, L., Johnson, D., Mekuria, F., Ngwenya, D., Ntlatlapa, N., Hart, A., Harding, C., and A. Lee, "First large TV white spaces trial in South Africa: A brief overview", 6th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), pp. 407-414, DOI 10.1109/ICUMT.2014.7002136, October 2014. [Mathee] Mathee, K., Mweemba, G., Pais, A., Stam, V., and M. Rijken, "Bringing Internet connectivity to rural Zambia using a collaborative approach", International Conference on Information and Communication Technologies and Development, pp. 1-12, DOI 10.1109/ICTD.2007.4937391, 2007. [McMahon] McMahon, R., Gurstein, M., Beaton, B., Donnell, S., and T. Whiteducke, "Making Information Technologies Work at the End of the Road", Journal of Information Policy, Vol. 4, pp. 250-269, DOI 10.5325/jinfopoli.4.2014.0250, 2014. [Meraki] Cisco Systems, "Meraki", 2016, <https://www.meraki.com/>. [Mexican] Varma, S., "Ignored by big companies, Mexican village creates its own mobile service", August 2013, <http://timesofindia.indiatimes.com/world/rest-of-world/ Ignored-by-big-companies-Mexican-village-creates-its-own- mobile-service/articleshow/22094736.cms>. [Mitchell] Mitchell, C., "Broadband At the Speed of Light: How Three Communities Built Next-Generation Networks", Institute for Local Self-Reliance (ILSR), April 2012, <http://ilsr.org/ wp-content/uploads/2012/04/muni-bb-speed-light.pdf>. [Neumann_a] Neumann, A., Lopez, E., and L. Navarro, "An evaluation of BMX6 for community wireless networks", In IEEE 8th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), pp. 651-658, DOI 10.1109/WiMOB.2012.6379145, 2012. [Neumann_b] Neumann, A., Lopez, E., and L. Navarro, "Evaluation of mesh routing protocols for wireless community networks", Computer Networks, Vol. 93, Part 2, pp. 308-323, December 2015, <http://dx.doi.org/10.1016/j.comnet.2015.07.018>. Saldana, et al. Informational [Page 34] RFC 7962 Alternative Network Deployments August 2016 [NewMexico] New Mexico Department of Information Technology, "Broadband Guide for Electric Utilities", CTC Technology & Energy, Version 1, April 2015, <http://www.doit.state.nm.us/broadband/reports/ NMBBP_FiberGuide_ElectricUtilities.pdf>. [Norris] Norris, P., "Digital Divide: Civic Engagement, Information Poverty, and the Internet Worldwide", Cambridge University Press, ISBN 0521807514, 2001. [Nungu] Nungu, A., Knutsson, B., and B. Pehrson, "On Building Sustainable Broadband Networks in Rural Areas", Technical Symposium at ITU Telecom World, pp. 135-140, October 2011. [NYTimes] Gall, C. and J. Glanz, "U.S. Promotes Network to Foil Digital Spying", The New York Times, April 2014, <http://www.nytimes.com/2014/04/21/us/ us-promotes-network-to-foil-digital-spying.html?_r=1>. [OLSR] OLSR.org, "OLSR", 2016, <http://www.olsr.org/>. [Openair] OpenAirInterface, "OpenAirInterface: 5G software alliance for democratising wireless innovation", 2016, <http://www.openairinterface.org/>. [OpenMesh] Open Mesh, "Open Mesh", 2016, <http://www.open-mesh.com/>. [Osmocom] Open Source Mobile Communications (Osmocom), "Cellular Infrastructure", GPRS bitrates, 2016, <https://osmocom.org/projects/osmopcu/wiki/GPRS_bitrates>. [PAWS] Sathiaseelan, A., Crowcroft, J., Goulden, M., Greiffenhagen, C., Mortier, R., Fairhurst, G., and D. McAuley, "Public Access WiFi Service (PAWS)", Digital Economy All Hands Meeting, University of Aberdeen, October 2012. [PIE] Pan, R., Natarajan, P., Baker, F., and G. White, "PIE: A Lightweight Control Scheme To Address the Bufferbloat Problem", Work in Progress, draft-ietf-aqm-pie-09, August 2016. Saldana, et al. Informational [Page 35] RFC 7962 Alternative Network Deployments August 2016 [Pietrosemoli] Pietrosemoli, E., Zennaro, M., and C. Fonda, "Low cost carrier independent telecommunications infrastructure", Global Information Infrastructure and Networking Symposium, pp. 1-4, DOI 10.1109/GIIS.2012.6466655, December 2012. [Rangenetworks] Range Networks, "Range Networks", 2016, <http://www.rangenetworks.com>. [Redhook] Red Hook WIFI, "Red Hook WIFI, a project of the Red Hook Initiative", 2016, <http://redhookwifi.org/>. [Rey] Rey-Moreno, C., Bebea-Gonzalez, I., Foche-Perez, I., Quispe-Taca, R., Linan-Benitez, L., and J. Simo-Reigadas, "A telemedicine WiFi network optimized for long distances in the Amazonian jungle of Peru", Proceedings of the 3rd Extreme Conference on Communication: The Amazon Expedition, Article No. 9, DOI 10.1145/2414393.2414402, 2011. [RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G., and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918, February 1996, <http://www.rfc-editor.org/info/rfc1918>. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, DOI 10.17487/RFC2328, April 1998, <http://www.rfc-editor.org/info/rfc2328>. [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition of Explicit Congestion Notification (ECN) to IP", RFC 3168, DOI 10.17487/RFC3168, September 2001, <http://www.rfc-editor.org/info/rfc3168>. [RFC3626] Clausen, T., Ed. and P. Jacquet, Ed., "Optimized Link State Routing Protocol (OLSR)", RFC 3626, DOI 10.17487/RFC3626, October 2003, <http://www.rfc-editor.org/info/rfc3626>. [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, <http://www.rfc-editor.org/info/rfc4271>. Saldana, et al. Informational [Page 36] RFC 7962 Alternative Network Deployments August 2016 [RFC6126] Chroboczek, J., "The Babel Routing Protocol", RFC 6126, DOI 10.17487/RFC6126, April 2011, <http://www.rfc-editor.org/info/rfc6126>. [RFC6297] Welzl, M. and D. Ros, "A Survey of Lower-than-Best-Effort Transport Protocols", RFC 6297, DOI 10.17487/RFC6297, June 2011, <http://www.rfc-editor.org/info/rfc6297>. [RFC7181] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg, "The Optimized Link State Routing Protocol Version 2", RFC 7181, DOI 10.17487/RFC7181, April 2014, <http://www.rfc-editor.org/info/rfc7181>. [RFC7567] Baker, F., Ed. and G. Fairhurst, Ed., "IETF Recommendations Regarding Active Queue Management", BCP 197, RFC 7567, DOI 10.17487/RFC7567, July 2015, <http://www.rfc-editor.org/info/rfc7567>. [Samanta] Samanta, V., Knowles, C., Wagmister, J., and D. Estrin, "Metropolitan Wi-Fi Research Network at the Los Angeles State Historic Park", The Journal of Community Informatics, Vol. 4, No. 1, May 2008, <http://ci-journal.net/index.php/ciej/article/ viewArticle/427>. [Sathiaseelan_a] Sathiaseelan, A., Rotsos, C., Sriram, C., Trossen, D., Papadimitriou, P., and J. Crowcroft, "Virtual Public Networks", In IEEE 2013 Second European Workshop on Software Defined Networks (EWSDN) pp. 1-6, DOI 10.1109/EWSDN.2013.7, October 2013. [Sathiaseelan_b] Sathiaseelan, A. and J. Crowcroft, "LCD-Net: Lowest Cost Denominator Networking", ACM SIGCOMM Computer Communication Review, Vol. 43, No. 2, April 2013, <http://dx.doi.org/10.1145/2479957.2479966>. [Sathiaseelan_c] Sathiaseelan, A., Mortier, R., Goulden, M., Greiffenhagen, C., Radenkovic, M., Crowcroft, J., and D. McAuley, "A Feasibility Study of an In-the-Wild Experimental Public Access WiFi Network", Proceedings of the Fifth ACM Symposium on Computing for Development, pp. 33-42, DOI 10.1145/2674377.2674383, 2014. Saldana, et al. Informational [Page 37] RFC 7962 Alternative Network Deployments August 2016 [SDG] United Nations, "Sustainable Development Goals", Sustainable Development Knowledge Platform, 2015, <https://sustainabledevelopment.un.org/?menu=1300>. [Seither] Seither, D., Koenig, A., and M. Hollick, "Routing performance of Wireless Mesh Networks: A practical evaluation of BATMAN advanced", IEEE 36th Conference on Local Computer Networks (LCN), pp. 897-904, DOI 10.1109/LCN.2011.6115569, October 2011. [Shi] Shi, J., Gui, L., Koutsonikolas, D., Qiao, C., and G. Challen, "A Little Sharing Goes a Long Way: The Case for Reciprocal Wifi Sharing", HotWireless '15 Proceedings of the 2nd International Workshop on Hot Topics in Wireless, DOI 10.1145/2799650.2799652, September 2015. [Simo_a] Simo-Reigadas, J., Morgado, E., Municio, E., Prieto-Egido, I., and A. Martinez-Fernandez, "Assessing IEEE 802.11 and IEEE 802.16 as backhaul technologies for rural 3G femtocells in rural areas of developing countries", Proceedings of EUCNC, 2014. [Simo_b] Simo-Reigadas, J., Martinez-Fernandez, A., Ramos-Lopez, J., and J. Seoane-Pascual, "Modeling and Optimizing IEEE 802.11 DCF for Long-Distance Links", IEEE Transactions on Mobile Computing, Vol. 9, Issue 6, pp. 881-896, DOI 10.1109/TMC.2010.27, 2010. [Simo_c] Simo-Reigadas, J., Martinez-Fernandez, A., Osuna, P., Lafuente, S., and J. Seoane-Pascual, "The Design of a Wireless Solar-Powered Router for Rural Environments Isolated from Health Facilities", IEEE Wireless Communications, Vol. 15, Issue 3, pp. 24-30, DOI 0.1109/MWC.2008.4547519, June 2008. [Simo_d] Simo-Reigadas, J., Municio, E., Morgado, E., Castro, E., Martinez-Fernandez, A., Solorzano, L., and I. Prieto- Egido, "Sharing low-cost wireless infrastructures with telecommunications operators to bring 3G services to rural communities", Computer Networks, Vol. 93, Issue P2, pp. 245-259, December 2015, <http://dx.doi.org/10.1016/j.comnet.2015.09.006>. [Spectrum] Laursen, L., "Software-Defined Radio Will Let Communities Build Their Own 4G Networks", November 2015, <http://spectrum.ieee.org/telecom/wireless/ softwaredefined-radio-will-let-communities-build-their- own-4g-networks>. Saldana, et al. Informational [Page 38] RFC 7962 Alternative Network Deployments August 2016 [Sprague] Sprague, K., Grijpink, F., Manyika, J., Moodley, L., Chappuis, B., Pattabiraman, K., and J. Bughin, "Offline and falling behind: Barriers to Internet adoption", McKinsey and Company, August 2014. [Tech] Kazansky, B., "In Red Hook, Mesh Network Connects Sandy Survivors Still Without Power", November 2012, <http://techpresident.com/news/23127/red-hook-mesh- network-connects-sandy-survivors-still-without-power>. [TidePools] Baldwin, J., "TidePools: Social WiFi", Parsons, the New School for Design, Doctoral dissertation, Master thesis, 2011, <http://www.scribd.com/doc/94601219/ TidePools-Social-WiFi-Thesis>. [UN] United Nations Statistics Division (UNSD), "Composition of macro geographical (continental) regions, geographical sub-regions, and selected economic and other groupings", October 2013, <http://unstats.un.org/unsd/methods/m49/ m49regin.htm#ftnc>. [UNStats] United Nations Statistics Division (UNSD), "Urban and total population by sex: 1996-2005", Table 6 - Demographic Yearbook 2005, <http://unstats.un.org/unsd/demographic/products/dyb/ dyb2005/notestab06.pdf>. [Vega_a] Vega, D., Cerda-Alabern, L., Navarro, L., and R. Meseguer, "Topology patterns of a community network: Guifi.net", IEEE 8th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), pp. 612-619, DOI 10.1109/WiMOB.2012.6379139, October 2012. [Vega_b] Vega, D., Baig, R., Cerda-Alabern, L., Medina, E., Meseguer, R., and L. Navarro, "A technological overview of the guifi.net community network", Computer Networks, Vol. 93, Issue P2, pp. 260-278, December 2015, <http://dx.doi.org/10.1016/j.comnet.2015.09.023>. [Village] Heimerl, K. and E. Brewer, "The Village Base Station", Proceedings of the 4th ACM Workshop on Networked Systems for Developing Regions, Article No. 14, DOI 10.1145/1836001.1836015, 2010. Saldana, et al. Informational [Page 39] RFC 7962 Alternative Network Deployments August 2016 [WiLD] Patra, R., Nedevschi, S., Surana, S., Sheth, A., Subramanian, L., and E. Brewer, "WiLDNet: Design and Implementation of High Performance WiFi Based Long Distance Networks", NSDI, Vol. 1, No. 1, pp. 1, April 2007. [WNDW] WNDW, "Wireless Networking in the Developing World, 3rd Edition", The WNDW Project, 2013, <http://wndw.net>. [WorldBank2016] World Bank, "World Development Report 2016: Digital Dividends", Washington, DC: The World Bank, ISBN 978-1-4648-0672-8, DOI 10.1596/978-1-4648-0671-1, 2016, <http://www-wds.worldbank.org/external/default/WDSContentS erver/WDSP/IB/2016/01/13/090224b08405ea05/2_0/Rendered/ PDF/World0developm0000digital0dividends.pdf>. [WSIS] International Telecommunications Union, "Declaration of Principles. Building the Information Society: A global challenge in the new millennium", WSIS-03 / GENEVA / DOC / 4-E, December 2003, <http://www.itu.int/wsis>. [YateBTS] YateBTS, "YateBTS", 2016, <http://yatebts.com/>. Acknowledgements This work has been partially funded by the CONFINE European Commission project (FP7 - 288535). Arjuna Sathiaseelan and Andres Arcia Moret were funded by the EU H2020 RIFE project (Grant Agreement no: 644663). Jose Saldana was funded by the EU H2020 Wi-5 project (Grant Agreement no: 644262). The editor and the authors of this document wish to thank the following individuals who have participated in the drafting, review, and discussion of this memo: Panayotis Antoniadis, Paul M. Aoki, Roger Baig, Jaume Barcelo, Steven G. Huter, Aldebaro Klautau, Rohan Mahy, Vesna Manojlovic, Mitar Milutinovic, Henning Schulzrinne, Rute Sofia, and Dirk Trossen. A special thanks to the GAIA Working Group chairs Mat Ford and Arjuna Sathiaseelan for their support and guidance. Saldana, et al. Informational [Page 40] RFC 7962 Alternative Network Deployments August 2016 Contributors Leandro Navarro U. Politecnica Catalunya Jordi Girona, 1-3, D6 Barcelona 08034 Spain Phone: +34 93 401 6807 Email: leandro@ac.upc.edu Carlos Rey-Moreno University of the Western Cape Robert Sobukwe road Bellville 7535 South Africa Phone: +27 (0)21 959 2562 Email: crey-moreno@uwc.ac.za Ioannis Komnios Democritus University of Thrace Department of Electrical and Computer Engineering Kimmeria University Campus Xanthi 67100 Greece Phone: +306945406585 Email: ikomnios@ee.duth.gr Steve Song Network Startup Resource Center Lunenburg, Nova Scotia Canada Phone: +1 902 529 0046 Email: stevesong@nsrc.org David Lloyd Johnson Meraka, CSIR 15 Lower Hope St Rosebank 7700 South Africa Phone: +27 (0)21 658 2740 Email: djohnson@csir.co.za Saldana, et al. Informational [Page 41] RFC 7962 Alternative Network Deployments August 2016 Javier Simo-Reigadas Escuela Tecnica Superior de Ingenieria de Telecomunicacion Campus de Fuenlabrada Universidad Rey Juan Carlos Madrid Spain Phone: +34 91 488 8428 Fax: +34 91 488 7500 Email: javier.simo@urjc.es Authors' Addresses Jose Saldana (editor) University of Zaragoza Dpt. IEC Ada Byron Building Zaragoza 50018 Spain Phone: +34 976 762 698 Email: jsaldana@unizar.es Andres Arcia-Moret University of Cambridge 15 JJ Thomson Avenue Cambridge FE04 United Kingdom Phone: +44 (0) 1223 763610 Email: andres.arcia@cl.cam.ac.uk Bart Braem iMinds Gaston Crommenlaan 8 (bus 102) Gent 9050 Belgium Phone: +32 3 265 38 64 Email: bart.braem@iminds.be Saldana, et al. Informational [Page 42] RFC 7962 Alternative Network Deployments August 2016 Ermanno Pietrosemoli The Abdus Salam ICTP Via Beirut 7 Trieste 34151 Italy Phone: +39 040 2240 471 Email: ermanno@ictp.it Arjuna Sathiaseelan University of Cambridge 15 JJ Thomson Avenue Cambridge CB30FD United Kingdom Phone: +44 (0)1223 763781 Email: arjuna.sathiaseelan@cl.cam.ac.uk Marco Zennaro The Abdus Salam ICTP Strada Costiera 11 Trieste 34100 Italy Phone: +39 040 2240 406 Email: mzennaro@ictp.it Saldana, et al. Informational [Page 43]

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