RFC 7962
Alternative Network Deployments: Taxonomy, Characterization, Technologies, and Architectures
Pages: 43
Informational
Informational
Part 1 of 2 – Pages 1 to 22
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 ArchitecturesAbstract
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.
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.
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
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.
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.
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.
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.
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.
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.
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
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].
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].
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.
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.
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.
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].
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.
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.
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
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.
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].
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]).
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