tech-invite   World Map     

IETF     RFCs     Groups     SIP     ABNFs    |    3GPP     Specs     Glossaries     Architecture     IMS     UICC    |    search     info

RFC 7962

 
 
 

Alternative Network Deployments: Taxonomy, Characterization, Technologies, and Architectures

Part 2 of 2, p. 22 to 43
Prev Section

 


prevText      Top      ToC       Page 22 
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.

Top      Up      ToC       Page 23 
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.

Top      Up      ToC       Page 24 
   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.

Top      Up      ToC       Page 25 
   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.

Top      Up      ToC       Page 26 
   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].

Top      Up      ToC       Page 27 
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.

Top      Up      ToC       Page 28 
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.

Top      Up      ToC       Page 29 
   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.

Top      Up      ToC       Page 30 
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.

Top      Up      ToC       Page 31 
   [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>.

Top      Up      ToC       Page 32 
   [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>.

Top      Up      ToC       Page 33 
   [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>.

Top      Up      ToC       Page 34 
   [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>.

Top      Up      ToC       Page 35 
   [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.

Top      Up      ToC       Page 36 
   [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>.

Top      Up      ToC       Page 37 
   [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.

Top      Up      ToC       Page 38 
   [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>.

Top      Up      ToC       Page 39 
   [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.

Top      Up      ToC       Page 40 
   [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.

Top      Up      ToC       Page 41 
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

Top      Up      ToC       Page 42 
   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

Top      Up      ToC       Page 43 
   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