Alternative Network Deployments. Taxonomy, characterization, technologies and architectures
draft-irtf-gaia-alternative-network-deployments-01
The information below is for an old version of the document.
draft-irtf-gaia-alternative-network-deployments-01
Global Access to the Internet for All J. Saldana, Ed.
Internet-Draft University of Zaragoza
Intended status: Informational A. Arcia-Moret
Expires: January 2, 2016 University of Cambridge
B. Braem
iMinds
E. Pietrosemoli
ICTP
A. Sathiaseelan
University of Cambridge
M. Zennaro
Abdus Salam ICTP
July 1, 2015
Alternative Network Deployments. Taxonomy, characterization,
technologies and architectures
draft-irtf-gaia-alternative-network-deployments-01
Abstract
This document presents a taxonomy of "Alternative Network
deployments", and a set of definitions and shared properties. It
also discusses the technologies employed in these network
deployments, and their differing architectural characteristics.
The term "Alternative Network Deployments" includes a set of network
access models that have emerged in the last decade with the aim of
bringing Internet connectivity to people, using topological,
architectural and business models different from the so-called
"traditional" ones, where a company deploys or leases the network
infrastructure for connecting the users, who pay a subscription fee
to be connected and make use of it.
Several initiatives throughout the world have built large scale
alternative Networks, using predominantly wireless technologies
(including long distance) due to the reduced cost of using the
unlicensed spectrum. Wired technologies such as fiber are also used
in some of these alternate networks. There are several types of
alternate networks: community networks, which are self-organized and
decentralized networks wholly owned by the community; networks owned
by individuals who act as 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, and finally there are networks that provide connectivity
by sharing wireless resources of the users.
Saldana, et al. Expires January 2, 2016 [Page 1]
Internet-Draft Alternative Network Deployments July 2015
The emergence of these networks can be motivated by different causes
such as the reluctance, or the impossibility, of network operators to
provide wired and cellular infrastructures to rural/remote areas. In
these cases, the networks have self sustainable business models that
provide more localized communication services as well as Internet
backhaul support through peering agreements with traditional network
operators. Some other times, networks are built as a complement and
an alternative to commercial Internet access provided by
"traditional" network operators.
The present classification considers different existing network
models such as Community Networks, open wireless services, user-
extensible services, traditional local Internet Service Providers
(ISPs), new global ISPs, etc. Different criteria are used in order
to build a classification as e.g., the ownership of the equipment,
the way the network is organized, the participatory model, the
extensibility, if they are driven by a community, a company or a
local stakeholder (public or private), etc.
According to the developed taxonomy, a characterization of each kind
of network is presented in terms of specific network characteristics
related to architecture, organization, etc.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 2, 2016.
Copyright Notice
Copyright (c) 2015 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
Saldana, et al. Expires January 2, 2016 [Page 2]
Internet-Draft Alternative Network Deployments July 2015
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Traditional networks . . . . . . . . . . . . . . . . . . 5
1.2. Criteria for the classification of Alternative Networks . 5
1.2.1. Commercial model / promoter . . . . . . . . . . . . . 5
1.2.2. Goals and motivation . . . . . . . . . . . . . . . . 6
1.2.3. Administrative model . . . . . . . . . . . . . . . . 6
1.2.4. Technologies employed . . . . . . . . . . . . . . . . 6
1.2.5. Typical scenarios . . . . . . . . . . . . . . . . . . 7
2. Classification of Alternative Networks . . . . . . . . . . . 7
2.1. Community Networks . . . . . . . . . . . . . . . . . . . 7
2.1.1. Free Networks . . . . . . . . . . . . . . . . . . . . 9
2.2. Wireless Internet Service Providers WISPs . . . . . . . . 10
2.3. Shared infrastructure model . . . . . . . . . . . . . . . 11
2.4. Crowdshared approaches, led by the people and third party
stakeholders . . . . . . . . . . . . . . . . . . . . . . 12
2.5. Testbeds for research purposes . . . . . . . . . . . . . 15
3. Scenarios where Alternative Networks are deployed . . . . . . 15
3.1. Digital Divide and Alternative Networks . . . . . . . . . 15
3.2. Urban vs. rural areas . . . . . . . . . . . . . . . . . . 17
3.3. Gap between demanded and provided communications services 18
3.4. Topology patterns followed by Alternative Networks . . . 18
4. Technologies employed . . . . . . . . . . . . . . . . . . . . 19
4.1. Wired . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.2. Wireless . . . . . . . . . . . . . . . . . . . . . . . . 19
4.2.1. Antennas . . . . . . . . . . . . . . . . . . . . . . 19
4.2.2. Physical link length . . . . . . . . . . . . . . . . 20
4.2.2.1. Line-of-Sight . . . . . . . . . . . . . . . . . . 20
4.2.2.2. Transmitted and Received Power . . . . . . . . . 20
4.2.3. Media Access Control (MAC) Protocols for Wireless
Links . . . . . . . . . . . . . . . . . . . . . . . . 21
4.2.3.1. 802.11 (Wi-Fi) . . . . . . . . . . . . . . . . . 21
4.2.3.2. GSM . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.3.3. Dynamic Spectrum . . . . . . . . . . . . . . . . 23
5. Upper layers . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1. Layer 3 . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1.1. IP addressing . . . . . . . . . . . . . . . . . . . . 24
5.1.2. Routing protocols . . . . . . . . . . . . . . . . . . 25
5.1.2.1. Traditional routing protocols . . . . . . . . . . 25
5.1.2.2. Mesh routing protocols . . . . . . . . . . . . . 25
Saldana, et al. Expires January 2, 2016 [Page 3]
Internet-Draft Alternative Network Deployments July 2015
5.2. Transport layer . . . . . . . . . . . . . . . . . . . . . 26
5.2.1. Traffic Management when sharing network resources . . 26
5.2.2. Multi-hop issues . . . . . . . . . . . . . . . . . . 26
5.3. Services provided . . . . . . . . . . . . . . . . . . . . 27
5.3.1. Intranet services . . . . . . . . . . . . . . . . . . 27
5.3.2. Access to the Internet . . . . . . . . . . . . . . . 28
5.3.2.1. Web browsing proxies . . . . . . . . . . . . . . 28
5.3.2.2. Use of VPNs . . . . . . . . . . . . . . . . . . . 28
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 28
7. Contributing Authors . . . . . . . . . . . . . . . . . . . . 28
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
9. Security Considerations . . . . . . . . . . . . . . . . . . . 30
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.1. Normative References . . . . . . . . . . . . . . . . . . 30
10.2. Informative References . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction
Several initiatives throughout the world have built large scale
networks that are alternative to the traditional network operator
deployments using predominantly wireless technologies (including long
distance) due to the reduced cost of using the unlicensed spectrum.
Wired technologies such as fiber are also used in some of these
alternate networks. There are several types of alternate
deployments: community networks are self-organized and decentralized
networks wholly owned by the community; networks owned by individuals
who act 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,
and finally there are networks that provide connectivity by sharing
wireless resources of the users.
The emergence of these networks can be motivated by different causes,
as the reluctance, or the impossibility, of network operators to
provide wired and cellular infrastructures to rural/remote areas
[Pietrosemoli]. In these cases, the networks have self sustainable
business models that provide more localized communication services as
well as Internet backhaul support (i.e. uplink connection) through
peering agreements with traditional network operators. Some other
times, they are built as a complement and an alternative to
commercial Internet access provided by "traditional" network
operators.
One of the aims of the Global Access to the Internet for All (GAIA)
IRTF initiative is "to document and share deployment experiences and
research results to the wider community through scholarly
publications, white papers, Informational and Experimental RFCs,
Saldana, et al. Expires January 2, 2016 [Page 4]
Internet-Draft Alternative Network Deployments July 2015
etc." In line with this objective, this document is intended to
propose a classification of these "Alternative Network Deployments".
This term includes a set of network access models that have emerged
in the last decade with the aim of bringing Internet connectivity to
people, following topological, architectural and business models
different from the so-called "traditional" ones, where a company
deploys the infrastructure connecting the users, who pay a
subscription fee to be connected and make use of it. The document is
intended to be largely descriptive providing a broad overview of
initiatives, technologies and approaches employed in these networks.
Research references describing each kind of network are also
provided.
1.1. Traditional networks
In this document we will use the term "traditional networks" to
denote those sharing these characteristics:
- Regarding scale, they are usually large networks spanning entire
regions.
- Top-down control of the network and centralized approaches are
used.
- They require a substantial investment in infrastructure.
- Users in traditional networks tend to be passive consumers, as
opposed to active stakeholders, in the network design, deployment,
operation and maintenance.
1.2. Criteria for the classification of Alternative Networks
The classification of Alternative Network Deployments, presented in
this document, is based on the next criteria:
1.2.1. Commercial model / promoter
The entity (or entities) or individuals promoting an Alternative
Network can be:
o a community of users
o a public stakeholder
o a private company
o crowdshared approaches are also considered
Saldana, et al. Expires January 2, 2016 [Page 5]
Internet-Draft Alternative Network Deployments July 2015
o shared infrastructure
o they can be created as a testbed by a research or academic entity
1.2.2. Goals and motivation
Alternative networks can also be classified according to the
underlying motivation for them, i.e., addressing deployment and usage
hurdles:
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 on-going operational costs (such as backhaul or network
administration)
o leveraging expertise
o reducing hurdles to adoption (digital literacy; literacy, in
general; relevance, etc.)
o extending coverage to underserved areas (users and communities)
o network neutrality guarantees
1.2.3. Administrative model
o centralized
o distributed
1.2.4. Technologies employed
o normal Wi-Fi
o Wi-Fi modified for long distances (WiLD), either with CSMA/CA or
with an alternative TDMA MAC [Simo_b]
o 802.16-compliant systems over non-licensed bands
o Dynamic Spectrum Solutions (e.g. based on the use of white spaces)
o satellite solutions
o low-cost optical fiber systems
Saldana, et al. Expires January 2, 2016 [Page 6]
Internet-Draft Alternative Network Deployments July 2015
1.2.5. Typical scenarios
The scenarios where Alternative Networks are usually deployed can be:
o urban
o rural
o rural in developing countries
2. Classification of Alternative Networks
This section classifies Alternative Networks (ANs) according to their
intended usage. Each of them has different incentive structures,
maybe common technological challenges, but most importantly
interesting usage challenges which feeds 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 "Criteria for the classification of Alternative Networks"
subsection.
2.1. Community Networks
+--------------------+----------------------------------------------+
| Commercial | community |
| model/promoter | |
+--------------------+----------------------------------------------+
| Goals and | reducing hurdles; to serve underserved |
| motivation | areas; network neutrality |
+--------------------+----------------------------------------------+
| Administration | distributed |
+--------------------+----------------------------------------------+
| Technologies | Wi-Fi, optical fiber |
+--------------------+----------------------------------------------+
| Typical scenarios | urban and rural |
+--------------------+----------------------------------------------+
Table 1: Community Networks' characteristics summary
Community Networks are large-scale, distributed, self-managed
networks sharing these characteristics:
- They are built and organized in a decentralized and open manner.
- They start and grow organically, they are open to participation
from everyone, sometimes sharing an open peering agreement.
Saldana, et al. Expires January 2, 2016 [Page 7]
Internet-Draft Alternative Network Deployments July 2015
Community members directly contribute active (not just passive)
network infrastructure.
- Knowledge about building and maintaining the network and ownership
of the network itself is decentralized and open. Community members
have an obvious and direct form of organizational control over the
overall operation of the network in their community (not just their
own participation in the network).
- 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,
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 minimum
governance infrastructure is required in order to coordinate IP
addressing, routing, etc. An example of this kind of Community
Network is described in [Braem]. These networks follow a
participatory model, which has been shown effective in connecting
geographically dispersed people, thus enhancing and extending digital
Internet rights.
The fact of the 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.
In Community Networks, the profit can only be made by services and
not by the infrastructure itself, because the infrastructure is
neutral, free, and open (traditional Internet Service Providers,
ISPs, base their business on the control of the infrastructure). In
Community Networks, everybody keeps the ownership of what he/she has
contributed.
Community Networks may also be called "Free Networks" or even
"Network Commons" [FNF]. The majority of Community Networks
accomplishes the definition of Free Network, included in the next
subsection.
Saldana, et al. Expires January 2, 2016 [Page 8]
Internet-Draft Alternative Network Deployments July 2015
2.1.1. Free Networks
A definition of Free Network (which may be the same as Community
Network) is proposed by the Free Network Foundation (see
http://thefnf.org) as:
"A free network equitably grants the following freedoms to all:
Freedom 0 - The freedom to communicate for any purpose, without
discrimination, interference, or interception.
Freedom 1 - The freedom to grow, improve, communicate across, and
connect to the whole network.
Freedom 2- The freedom to study, use, remix, and share any network
communication mechanisms, in their most reusable forms."
The principles of Free, Open and Neutral Networks have also been
summarized (see http://guifi.net/en/FONCC) this way:
- 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.
Saldana, et al. Expires January 2, 2016 [Page 9]
Internet-Draft Alternative Network Deployments July 2015
2.2. Wireless Internet Service Providers WISPs
+--------------------+----------------------------------------------+
| Commercial | company |
| model/promoter | |
+--------------------+----------------------------------------------+
| Goals and | to serve underserved areas; to reduce CAPEX |
| motivation | in Internet access |
+--------------------+----------------------------------------------+
| Administration | centralized |
+--------------------+----------------------------------------------+
| Technologies | wireless, unlicensed frequencies |
+--------------------+----------------------------------------------+
| Typical scenarios | rural |
+--------------------+----------------------------------------------+
Table 2: WISPs' characteristics summary
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 incumbent telcos or ISPs.
WISPs often use wireless point-to-point or point-to-multipoint in the
unlicensed frequencies but licensed frequency use is common too
especially in regions where unlicensed spectrum is either perceived
as crowded or where unlicensed spectrum may have 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 [Airjaldi] in India that have expanded from local service
into multiple locations.
Since 2006, the deployment of cloud-managed WISPs has been possible
with companies like Meraki and later OpenMesh and others. Until
recently, however, most of these services have been aimed at
industrialized markets. Everylayer [Everylayer], launched in 2014,
is the first cloud-managed WISP service aimed at emerging markets.
Saldana, et al. Expires January 2, 2016 [Page 10]
Internet-Draft Alternative Network Deployments July 2015
2.3. Shared infrastructure model
+----------------+--------------------------------------------------+
| Commercial | shared: companies and users |
| model/promoter | |
+----------------+--------------------------------------------------+
| Goals and | to eliminate a CAPEX barrier (to operators); |
| motivation | lower the OPEX (supported by the community); to |
| | extend coverage to underserved areas |
+----------------+--------------------------------------------------+
| Administration | distributed |
+----------------+--------------------------------------------------+
| Technologies | wireless in non-licensed bands and/or low-cost |
| | fiber |
+----------------+--------------------------------------------------+
| Typical | rural areas, and more particularly rural areas |
| scenarios | in developing regions |
+----------------+--------------------------------------------------+
Table 3: Shared infrastructure characteristics summary
In conventional networks, the operator usually owns the
telecommunications infrastructures required for the service, or
sometimes rents these infrastructures to other companies. The
problem arises in large areas with low population density, in which
neither the operator nor other companies have deployed infrastructure
and such deployments are not likely to happen due to the low
potential return of investment.
When users already own a deployed infrastructure, either individually
or as a community, sharing that infrastructure with an operator
represents an interesting win-win solution that starts to be
exploited in some contexts. For the operator, this supposes a
significant reduction of the initial investment needed to provide
services in small rural localities because the CAPEX is only
associated to the access network, as renting capacity in the users'
network for backhauling supposes is only an increment in the OPEX.
This approach also benefits the users in two ways: they obtain
improved access to telecommunications services that would not be
otherwise accessible, and they can get some income from the operator
that helps to afford the network's OPEX, 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, there are complete technical solutions for
low-cost 3G coverage using the Internet as a backhaul. If a user or
Saldana, et al. Expires January 2, 2016 [Page 11]
Internet-Draft Alternative Network Deployments July 2015
community of users has an IP network connected to the Internet with
some capacity in excess, 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
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 European Commission FP7
TUCAN3G project, (see http://www.ict-tucan3g.eu/) which deployed
demonstrative networks in two regions in the Amazon forest in Peru.
In these networks [Simo_a], the operator and several rural
communities have cooperated to provide services through rural
networks built up with WiLD links [WiLD]. In these cases, the
networks belong to the health public authorities and were deployed
with funds come from international cooperation for telemedicine
purposes. Publications that justify the feasibility of this approach
can also been found in that website.
2.4. Crowdshared approaches, led by the people and third party
stakeholders
+-----------------------+-------------------------------------------+
| Commercial | community, public stakeholders, private |
| model/promoter | companies |
+-----------------------+-------------------------------------------+
| Goals and motivation | sharing connectivity and resources |
+-----------------------+-------------------------------------------+
| Administration | distributed |
+-----------------------+-------------------------------------------+
| Technologies | wireless |
+-----------------------+-------------------------------------------+
| Typical scenarios | urban and rural |
+-----------------------+-------------------------------------------+
Table 4: Crowdshared approaches characteristics summary
These networks can be defined as a set of nodes whose owners share
common interests (e.g. sharing connectivity; resources; 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
Saldana, et al. Expires January 2, 2016 [Page 12]
Internet-Draft Alternative Network Deployments July 2015
examples are described in [PAWS] and [Sathiaseelan_c]. Other example
is constituted by the networks created and managed by City Councils
(e.g., [Heer]).
In the same way, some companies [Fon] develop and sell Wi-Fi routers
with a dual access: a Wi-Fi network for the user, and a shared one.
A user community is created, and people can join the network in
different ways: they can buy a router, so they share their connection
and in turn they get access to all the routers associated to the
community. Some users can even get some revenue every time another
user connects to their Wi-Fi spot. Other users can just buy some
passes in order to use the network. Some telecommunications
operators can collaborate with the community, including in their
routers the possibility of creating these two networks.
As in the case of main Internet Service Providers in France,
Community Networks for urban areas are conceived as a set of APs
sharing a common SSID among the clients favouring the nomadic access.
For users in France, ISPs promise to cause a little impact on their
service agreement when the shared network service is activated on
clients' APs. Nowadays, millions of APs are deployed around the
country performing services of nomadism and 3G offloading, however as
some studies demonstrate, at walking speed, there is a fair chance of
performing file transfers [Castignani_a], [Castignani_b]. Scenarios
studied in France and Luxembourg show that the density of APs in
urban areas (mainly in downtown and residential areas) is quite big
and from different ISPs. Moreover, performed studies reveal that
aggregating available networks can be beneficial to the client by
using an application that manages the best connection among the
different networks. For improving the scanning process (or topology
recognition), which consumes the 90% of the connection/reconnection
process to the Community Network, the client may implement several
techniques for selecting the best AP [Castignani_c].
A Virtual Private Network (VPN) is created for public traffic, so it
is completely secure and separated from the owner's connection. The
network capacity shared may employ a low priority, a less-than-best-
effort or scavenger approach, so as not to harm the traffic of the
owner of the connection [Sathiaseelan_a].
The elements involved in a crowd-shared network are summarized below:
- Interest: a parameter capable of providing a measure (cost) of the
attractiveness of a node towards a specific location, in a specific
instance in time.
- Resources: A physical or virtual element of a global system. For
instance, bandwidth; energy; data; devices.
Saldana, et al. Expires January 2, 2016 [Page 13]
Internet-Draft Alternative Network Deployments July 2015
- The owner: End users who sign up for the service and share their
network capacity. As a counterpart, they can access another owners'
home access for free. The owner can be an end user or an entity
(e.g. operator; virtual operator; municipality) that is to be made
responsible for any actions concerning his/her device.
- 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.
- The Virtual Network Operator (VNO): An entity that acts in some
aspects as a network coordinator. It may provide services such as
initial authentication or registering, and eventually, trust
relationship storage. A VNO is not an ISP given that it does not
provide Internet access (e.g. infrastructure; naming). A VNO is
neither an Application Service Provider (ASP) since it does not
provide user services. Virtual Operators may also be stakeholders
with socio-environmental objectives. They can be a local government,
grass root user communities, charities, or even content operators,
smart grid operators, etc. They are the ones who actually run the
service.
- Network operators, who have a financial incentive to lease out the
unused capacity [Sathiaseelan_b] at 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, the network operators are paid by the VNOs,
who in turn accomplish their socio-environmental role.
Saldana, et al. Expires January 2, 2016 [Page 14]
Internet-Draft Alternative Network Deployments July 2015
2.5. Testbeds for research purposes
+--------------------+----------------------------------------------+
| Commercial | research / academic entity |
| model/promoter | |
+--------------------+----------------------------------------------+
| Goals and | research |
| motivation | |
+--------------------+----------------------------------------------+
| Administration | centralized initially, but it may end up in |
| | a distributed model. |
+--------------------+----------------------------------------------+
| Technologies | wired and wireless |
+--------------------+----------------------------------------------+
| Typical scenarios | urban and rural |
+--------------------+----------------------------------------------+
Table 5: Testbeds' characteristics summary
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
distributed model in which other local stakeholders assume part of
the network administration [Rey].
3. Scenarios where Alternative Networks are deployed
Alternative Network Deployments are present in every part of the
world. Even in some high-income countries, these networks have been
built as an alternative to commercial ones managed by traditional
network operators. This section discusses the scenarios where
Alternative Networks have been deployed.
3.1. Digital Divide and Alternative Networks
Although there is no consensus on a precise definition for the term
"developing country", it is generally used to refer to nations with a
relatively lower standard of living. Developing countries have also
been defined as those which are in transition from traditional
lifestyles towards the modern lifestyle which began in the Industrial
Revolution. When it comes to quantify to which extent a country is a
developing country, the Human Development Index has been proposed by
the United Nations in order to consider the Gross National Income
(GNI), the life expectancy and the education level of the population
in a single indicator. Additionally, the Gini Index (World Bank
Saldana, et al. Expires January 2, 2016 [Page 15]
Internet-Draft Alternative Network Deployments July 2015
estimate) may be used to measure the inequality, as it estimates the
dispersion of the national income (see
http://data.worldbank.org/indicator/SI.POV.GINI).
However, at the beginning of the 90's the debates about how to
quantify development in a country were shaken by the appearance of
Internet and mobile phones, which many authors consider the beginning
of the Information Society. With the beginning of this Digital
Revolution, defining development based on Industrial Society concepts
started to be challenged, and links between digital development and
its impact on human development started to flourish. The following
dimensions are considered to be meaningful when measuring the digital
development state of a country: infrastructures (availability and
affordability); ICT (Information and Communications Technology)
sector (human capital and technological industry); digital literacy;
legal and regulatory framework; and content and services. The lack
or less extent of digital development in one or more of these
dimensions is what has been referred as Digital Divide. This divide
is a new vector of inequality which - as it happened during the
Industrial Revolution - generates a lot of progress at the expense of
creating a lot economic poverty and exclusion. The Digital Divide is
considered to be a consequence of other socio-economic divides,
while, at the same time, a reason for their rise.
In this context, the so-called "developing countries", in order not
to be left behind of this incipient digital revolution, motivated the
World Summit of the Information Society which aimed at achieving "a
people-centred, inclusive and development-oriented Information
Society, where everyone can create, access, utilize and share
information and knowledge, enabling individuals, communities and
peoples to achieve their full potential in promoting their
sustainable development and improving their quality of life" [WSIS],
and called upon "governments, private sector, civil society and
international organizations" to actively engage to accomplish it
[WSIS].
Most efforts from governments and international organizations focused
initially on improving and extending the existing infrastructure in
order not to leave their population behind. As an example, one of
the goals of the Digital Agenda for Europe [DAE] is "to increase
regular internet usage from 60% to 75% by 2015, and from 41% to 60%
among disadvantaged people."
Universal Access and Service plans have taken different forms in
different countries over the years, with very uneven success rates,
but in most cases inadequate to the scale of the problem. Given its
incapacity to solve the problem, some governments included Universal
Service and Access obligations to mobile network operators when
Saldana, et al. Expires January 2, 2016 [Page 16]
Internet-Draft Alternative Network Deployments July 2015
liberalizing the telecommunications market. In combination with the
overwhelming and unexpected uptake of mobile phones by poor people,
this has mitigated the low access indicators existing in many
developing countries at the beginning of the 90s [Rendon].
Although the contribution made by mobile network operators in
decreasing the access gap is undeniable, their model presents some
constraints that limit the development outcomes that increased
connectivity promises to bring. Prices, tailored for the more
affluent part of the population, remain unaffordable to many, who
invest large percentages of their disposable income in
communications. Additionally, the cost of prepaid packages, the only
option available for the informal economies existing throughout
developing countries, is high compared with the rate longer-term
subscribers pay.
The consolidation of many Alternative Networks (e.g. Community
Networks) in high income countries sets a precedent for civil society
members from the so-called developing countries to become more active
in the search for alternatives to provide themselves with affordable
access. Furthermore, Alternative Networks could contribute to other
dimensions of the digital development like increased human capital
and the creation of contents and services targeting the locality of
each network.
3.2. Urban vs. rural areas
The Digital Divide presented in the previous section is not only
present between countries, but within them too. This is specially
the case for rural inhabitants, which represents approximately 55% of
the world's population, from which 78% inhabit in developing
countries. Although it is impossible to generalize among them, there
exist some common features that have determined the availability of
ICT infrastructure in these regions. The disposable income of their
dwellers is lower than those inhabiting urban areas, with many
surviving on a subsistence economy. Many of them are located in
geographies difficult to access and exposed to extreme weather
conditions. This has resulted in the almost complete lack of
electrical infrastructure. This context, together with their low
population density, discourages telecommunications operators to
provide similar services to those provided to urban dwellers, since
they do not deem them profitable.
The cost of the wireless infrastructure required to set up a network,
including powering it (e.g. via solar energy), is within the range of
availability if not of individuals at least of entire communities.
The social capital existing in these areas can allow for Alternative
Network set-ups where a reduced number of nodes may cover communities
Saldana, et al. Expires January 2, 2016 [Page 17]
Internet-Draft Alternative Network Deployments July 2015
whose dwellers share the cost of the infrastructure and the gateway
and access it via inexpensive wireless devices. Some examples are
presented in [Pietrosemoli] and [Bernardi].
In this case, the lack of awareness and confidence of rural
communities to embark themselves in such tasks can become major
barriers to their deployment. Scarce technical skills in these
regions have also been pointed as a challenge for their success, but
the proliferation of urban Community Networks, where scarcity of
spectrum, scale, and heterogeneity of devices pose tremendous
challenges to their stability and the services they aim to provide,
has fuelled the creation of robust low-cost low-consumption low-
complexity off-the-shelf wireless devices which make much easier the
deployment and maintenance of these alternative infrastructures in
rural areas.
3.3. Gap between demanded and provided communications services
Beyond the Digital Divide, either international or domestic, there
are many situations in which the market fails to provide the
information and communications services demanded by the population.
When this happens permanently in an area, citizens may be compelled
to take a more active part in the design and implementation of ICT
solutions, hence promoting Alternative Networks.
3.4. Topology patterns followed by Alternative Networks
Alternative Networks, considered self-managed and self-sustained,
follow different topology patterns [Vega]. 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 fits fairly well a power law distribution.
Moreover, the network is composed of a high number of heterogeneous
devices with the common objective of freely connecting and increasing
the network coverage. 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 example corresponds to Guifi.net [Vega] with an
exponential grow rate in the number of operating nodes during the
last decade.
Regularly rural areas in these networks are connected through long-
distance links (the so-called community mesh approach) which in turn
convey the Internet connection to relevant organisations 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
Saldana, et al. Expires January 2, 2016 [Page 18]
Internet-Draft Alternative Network Deployments July 2015
capacity (or gain connection) to the network. Other proposals like
Virtual Public Networks [Sathiaseelan_a] can also extend the service.
4. Technologies employed
4.1. Wired
In many (developed or developing) countries it may happen that
national service providers may decline to provide connectivity to
tiny and isolated villages. So in some cases the villagers have
created their own optical fiber networks. It is the case of
Lowenstedt in Germany [Lowenstedt], or some parts of Guifi.net
[Cerda-Alabern].
4.2. Wireless
The vast majority of the Alternative Network Deployments are based on
different wireless technologies [WNDW]. Below we summarize topics to
be considered in such deployments. Different considerations about
the available options are presented, including physical and Media
Access Control (MAC) layers. In addition, the trends (and some
recommendations) when using these features in Alternative Networks
are summarized.
4.2.1. Antennas
Three kinds of antennas are suitable to be used in these networks:
omnidirectional, low-gain directional and high-gain directional
antennas.
For local access, omnidirectional antennas are the most useful, since
they provide the same coverage in all directions of the plane in
which they are located. Above and below this plane, the received
signal will diminish, so the maximum benefits are obtained when the
client is at approximately the same height as the Access Point.
For indoor clients, omnidirectional antennas are generally fine,
because the numerous reflections normally found in indoor
environments negate the advantage of using directional antennas.
For outdoor clients, directional antennas can be quite useful to
extend coverage to an Access Point fitted with an omnidirectional
one.
When building point-to-point links, the highest gain antennas are the
best choice, since their narrow beamwidth mitigates interference from
other users and can provide the longest links [Flickenger],
[Zennaro].
Saldana, et al. Expires January 2, 2016 [Page 19]
Internet-Draft Alternative Network Deployments July 2015
Despite the fact that the free space loss is directly proportional to
the square of the frequency, it is normally advisable to use higher
frequencies for point-to-point links when there is a clear line of
sight, because it is normally easier to get higher gain antennas, the
protection against interferences is better and the spectrum
saturation is lower. Deploying high gain antennas at both ends will
more than compensate for the additional free space loss.
On the contrary, lower frequencies offer advantages when the line of
sight may be blocked because they can leverage diffraction to reach
the intended receiver.
In the case of mesh networking, where the antenna should connect to
several other nodes, it is better to use omnidirectional antennas.
The same type of polarization must be used at both ends of any radio
link. For point-to-point links, parabolic antennas exist that may
transmit/receive two different signals simultaneously at the same
frequency but with orthogonal polarizations, thus permitting to
increase the achievable throughput significantly and to improve the
protection to multipath and to other transmission impairments.
4.2.2. Physical link length
4.2.2.1. Line-of-Sight
For short distance transmission, there is no strict requirement of
line of sight between the transmitter and the receiver, and multipath
can guarantee communication despite the existence of obstacles in the
direct path.
For longer distances, the first requirement is the existence of an
unobstructed line of sight between the transmitter and the receiver.
For very long paths, the earth curvature is an obstacle that must be
cleared, but the trajectory of the radio beam is not strictly a
straight line due to the bending of the rays as a consequence of non-
uniformities of the atmosphere. Most of the time this bending will
mean that the radio horizon extends further than the optical horizon.
4.2.2.2. Transmitted and Received Power
Once a clear radio-electric line of sight is obtained, it is required
that the received power is significantly above the sensitivity of the
receiver, by what is known as the "link margin". The greater the
link margin, the more reliable the link. For mission critical
applications 20 dB margin is suggested, but for non critical ones 10
dB might suffice.
Saldana, et al. Expires January 2, 2016 [Page 20]
Internet-Draft Alternative Network Deployments July 2015
The sensitivity of the receiver decreases with the transmission
speed, so more power is needed at greater transmission speeds.
Different options can be considered in order to achieve a given link
margin (also called "fade margin"):
a) To increase the output power.The maximum transmitted power is
specified by each country's regulation, and for unlicensed
frequencies is much lower than for licensed frequencies.
b) To increase the antenna gain. There is no limit in the gain of
the receiving antenna, but high gain antennas are bulkier, present
more wind resistance and require sturdy mounts to comply with tighter
alignment requirements. The transmitter antenna gain is also
regulated and can be different for point-to-point as for point-to-
multipoint links.
c) To reduce the propagation loss, by using a more favorable
frequency or a shorter path.
d) To use a more sensitive receiver. Receiver sensitivity can be
improved by using better circuits, but it is ultimately limited by
the thermal noise, which is proportional to temperature and
bandwidth. One can increase the sensitivity by using a smaller
receiving bandwidth, or by settling to lower throughput even in the
same receiver bandwidth.
4.2.3. Media Access Control (MAC) Protocols for Wireless Links
Different protocols for Media Access Control, 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.
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,
as e.g. the European Telecommunications Standards Institute (ETSI).
4.2.3.1. 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) issued in 2011
reaches up to 866.7 Mbit/s. In 2012, the IEEE issued the 802.11-2012
Standard that consolidates all the previous amendments. The document
is freely downloadable from IEEE Standards [IEEE].
Saldana, et al. Expires January 2, 2016 [Page 21]
Internet-Draft Alternative Network Deployments July 2015
4.2.3.1.1. Deployment planning for 802.11 wireless networks
To provide physical connectivity, wireless network devices must
operate in the same part of the radio spectrum. This means that
802.11a radios will talk to 802.11a radios at around 5 GHz, and
802.11b/g radios will talk to other 802.11b/g radios at around 2.4
GHz. But an 802.11a device cannot interoperate with an 802.11b/g
device, since they use completely different parts of the
electromagnetic spectrum. More specifically, wireless interfaces
must agree on a common channel. If one 802.11b radio card is set to
channel 2 while another is set to channel 11, then the radios cannot
communicate with each other.
Each 802.11 device can operate in one of four possible modes:
1. Master mode (also called AP or infrastructure mode) is used to
create a service that looks like a traditional Access Point.
Wireless interfaces in master mode can only communicate with
interfaces that are associated with them in managed mode.
2. Managed mode is sometimes also referred to as client mode.
Wireless interfaces in managed mode will join a network created by a
master, and will automatically change their channel to match it.
Managed mode interfaces do not communicate with each other directly,
and only communicate with an associated master.
3. Ad-hoc mode creates a multipoint-to-multipoint network where
there is no single master node or AP. In ad-hoc mode, each wireless
interface communicates directly with its neighbors. Ad-hoc mode is
often also called Mesh Networking.
4. Monitor mode is used by some tools (such as Kismet) to passively
listen to all radio traffic on a given channel.
When implementing a point-to-point or point-to-multipoint link, one
radio will typically operate in master mode, while the other(s)
operate in managed mode. Ad-hoc is more flexible but has a number of
performance issues as compared to using the master / managed modes.
4.2.3.1.2. Long Distances in 802.11
The MAC protocol in 802.11 is called CSMA/CA (Carrier Sense Multiple
Access with Collision Avoidance) and was designed for short
distances; the transmitter expects the reception of an acknowledgment
for each transmitted unicast packet; 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, the distance has a
Saldana, et al. Expires January 2, 2016 [Page 22]
Internet-Draft Alternative Network Deployments July 2015
significant negative impact on the 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 (Time Division Multiple Access). Low cost
equipment using these techniques can offer high throughput at
distances above 100 kilometers.
4.2.3.2. GSM
GSM (Global System for Mobile Communications), from ETSI, has also
been used in Alternative Networks as Layer 2 option, as explained in
[Mexican].
4.2.3.3. Dynamic Spectrum
Some Alternative Networks make use of TV White Spaces - a set of UHF
and VHF television frequencies that can be utilized by secondary
users in locations where it is 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 which are able to modify their
frequency, power and modulation techniques to meet the strict
operating conditions required for secondary users.
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.2013] - an adaptation of the 802.11 standard
for TV white space bands and (ii) the IEEE 802.22 standard
[IEEE.802-22.2011] for long-range rural communication.
4.2.3.3.1. 802.11af
802.11af [IEEE.802-11AF.2013] 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
modulation but with improved in-building penetration and outdoor
coverage. The maximum data rate achievable is 426.7 Mbps for
countries with 6/7 MHz channels and 568.9 Mbps for countries with 8
Saldana, et al. Expires January 2, 2016 [Page 23]
Internet-Draft Alternative Network Deployments July 2015
MHz channels. Coverage is typically limited to 1km 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.
4.2.3.3.2. 802.22
802.22 [IEEE.802-22.2011] is a standard developed specifically for
long range rural communications in TV white space frequencies and
first approved in July 2011. The standard is similar to the 802.16
(WiMax) [IEEE.802-16.2008] standard with an added cognitive radio
ability. The maximum throughput of 802.22 is 22.6 Mbps 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 (CPEs) are sent
before slots destined for nearby CPEs.
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 white space TV
channel with the CPE devices. The standard also includes a co-
existence 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.
5. Upper layers
5.1. Layer 3
5.1.1. IP addressing
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
presents a challenge to Community Networks.
Saldana, et al. Expires January 2, 2016 [Page 24]
Internet-Draft Alternative Network Deployments July 2015
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.
5.1.2. Routing protocols
As stated in previous sections, Alternative Networks are composed of
possibly different layer 2 devices, resulting in a mesh of nodes.
Connection between different nodes is not guaranteed and the link
stability can vary strongly over time. To tackle this, some
Alternative Networks use mesh network routing protocols while other
networks use more traditional routing protocols. Some networks
operate multiple routing protocols in parallel. For example, they
use a mesh protocol inside different islands and use traditional
routing protocols to connect these islands.
5.1.2.1. 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].
5.1.2.2. Mesh routing protocols
A large number of Alternative Networks use the Optimized Link State
Routing Protocol (OLSR) routing protocol as defined in [RFC3626].
The pro-active link state routing protocol is a good match with
Alternative Networks because it has good performance in mesh networks
where nodes have multiple interfaces.
The Better Approach To Mobile Adhoc Networking (BATMAN) [Abolhasan]
protocol was developed by members of the Freifunk community. The
protocol handles all routing at layer 2, creating one bridged
network.
Parallel to BGP, some networks also run the BatMan-eXperimental
(BMX6) protocol [Neumann]. This is an advanced version of the BATMAN
protocol which is based on IPv6 and tries to exploit the social
structure of Alternative Networks.
Saldana, et al. Expires January 2, 2016 [Page 25]
Internet-Draft Alternative Network Deployments July 2015
5.2. Transport layer
5.2.1. Traffic Management when sharing network resources
When network resources are shared, a special care has to be put on
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. There should be an
adequate Active Queue Management (AQM) mechanism that implements a
Lower-than-best-effort (LBE) [RFC6297] policy for the user and
protects the sharer. Achieving LBE behavior requires the appropriate
tuning of the well known mechanisms such as Explicit Congestion
Notification (ECN) [RFC3168], or Random Early Detection (RED)
[RFC2309], or other more recent AQM mechanisms such as Controlled
Delay (CoDel) and [I-D.ietf-aqm-codel] PIE (Proportional Integral
controller Enhanced) [I-D.ietf-aqm-pie] that aid on keeping low
latency.
However, other bottlenecks besides client's access bottleneck may not
be controlled by the previously mentioned protocols. Therefore,
recently proposed transport protocols like LEDBAT [Ros], [Komnios]
with the purpose of transporting scavenger traffic may be a solution.
LEDBAT requires the cooperation of both the client and the server to
achieve certain target delay, therefore controlling the impact of the
user along all the path.
There are applications that manage aspects of the network from the
sharer side and from the client side. From sharer's side, there are
applications to centralize the management of the APs conforming the
network that have been recently proposed by means of SDN
[Sathiaseelan_a], [Suresh]. There are also other proposals such as
Wi2Me [Lampropulos] that manage the connection to several Community
Networks from the client's side. These applications have shown to
improve the client performance compared to a single-Community Network
client.
5.2.2. Multi-hop issues
On the other hand, transport protocols inside a multiple hop wireless
mesh network are likely to suffer performance degradation for
multiple reasons, e.g., hidden terminal problem, unnecessary delays
on the TCP ACK clocking that decrease the throughout or route
changing [Hanbali]. There are some options for network
configuration. The implementation of an easy-to-adopt solution for
TCP over mesh networks may be implemented from two different
perspectives. One way is to use a TCP-proxy to transparently deal
Saldana, et al. Expires January 2, 2016 [Page 26]
Internet-Draft Alternative Network Deployments July 2015
with the different impairments ([RFC3135]). Another way is to adopt
end-to-end solutions for monitoring the connection delay so that the
receiver adapts the TCP reception window (rwnd) [Castignani_c].
Similarly, the ACK Congestion Control (ACKCC) mechanism [RFC5690]
could deal with TCP-ACK clocking impairments due to inappropriate
delay on ACK packets. ACKCC compensates in an end-to-end fashion the
throughput degradation due to the effect of media contention as well
as the unfairness experienced by multiple uplink TCP flows in a
congested Wi-Fi access.
5.3. Services provided
This section provides an overview of the services between hosts
inside the network. They can be divided into Intranet services,
connecting hosts between them, and Internet services, connecting to
nodes outside the network.
5.3.1. Intranet services
Intranet services can include, but are not limited to:
- VoIP (e.g. with SIP)
- Remote desktop (e.g. using my home computer and my Internet
connection when I am on holidays in a village).
- FTP file sharing (e.g. distribution of Linux software).
- P2P file sharing.
- Public video cameras.
- DNS.
- Online games servers.
- Jabber instant messaging.
- IRC chat.
- Weather stations.
- NTP.
- Network monitoring.
- Videoconferencing / streaming.
Saldana, et al. Expires January 2, 2016 [Page 27]
Internet-Draft Alternative Network Deployments July 2015
- Radio streaming.
5.3.2. Access to the Internet
5.3.2.1. Web browsing proxies
A number of federated proxies may provide web browsing service for
the users. Other services (file sharing, skype, etc.) are not
usually allowed in many Alternative Networks due to bandwidth
limitations.
5.3.2.2. 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.
6. 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:
Paul M. Aoki, Roger Baig, Jaume Barcelo, Steven G. Huter, Rohan
Mahy, Rute Sofia, Dirk Trossen.
A special thanks to the GAIA Working Group chairs Mat Ford and Arjuna
Sathiaseelan for their support and guidance.
7. Contributing Authors
Leandro Navarro
U. Politecnica Catalunya
Jordi Girona, 1-3, D6
Barcelona 08034
Spain
Phone: +34 934016807
Email: leandro@ac.upc.edu
Saldana, et al. Expires January 2, 2016 [Page 28]
Internet-Draft Alternative Network Deployments July 2015
Carlos Rey-Moreno
University of the Western Cape
Robert Sobukwe road
Bellville 7535
South Africa
Phone: 0027219592562
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
Village Telco Limited
Halifax
Canada
Phone:
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
Javier Simo-Reigadas
Escuela Tecnica Superior de Ingenieria de Telecomunicacion
Campus de Fuenlabrada
Universidad Rey Juan Carlos
Madrid
Spain
Phone: 91 488 8428 / 7500
Email: javier.simo@urjc.es
Saldana, et al. Expires January 2, 2016 [Page 29]
Internet-Draft Alternative Network Deployments July 2015
8. IANA Considerations
This memo includes no request to IANA.
9. Security Considerations
No security issues have been identified for this document.
10. References
10.1. Normative References
[IEEE] Institute of Electrical and Electronics Engineers, IEEE,
"IEEE Standards association", 2012.
[IEEE.802-11AF.2013]
"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 Standard 802.11af, Oct
2009, <http://standards.ieee.org/getieee802/
download/802.11af-2013.pdf>.
[IEEE.802-16.2008]
"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
Standard 802.16, Jun 2008,
<http://standards.ieee.org/getieee802/
download/802.16-2012.pdf>.
[IEEE.802-22.2011]
"Information technology - Telecommunications and
information exchange between systems - 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 Standard
802.22, Jul 2011, <http://standards.ieee.org/getieee802/
download/802.11af-2013.pdf>.
[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
E. Lear, "Address Allocation for Private Internets", BCP
5, RFC 1918, February 1996.
Saldana, et al. Expires January 2, 2016 [Page 30]
Internet-Draft Alternative Network Deployments July 2015
[RFC2309] Braden, B., Clark, D., Crowcroft, J., Davie, B., Deering,
S., Estrin, D., Floyd, S., Jacobson, V., Minshall, G.,
Partridge, C., Peterson, L., Ramakrishnan, K., Shenker,
S., Wroclawski, J., and L. Zhang, "Recommendations on
Queue Management and Congestion Avoidance in the
Internet", RFC 2309, April 1998.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC3135] Border, J., Kojo, M., Griner, J., Montenegro, G., and Z.
Shelby, "Performance Enhancing Proxies Intended to
Mitigate Link-Related Degradations", RFC 3135, June 2001.
[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP", RFC
3168, September 2001.
[RFC3626] Clausen, T. and P. Jacquet, "Optimized Link State Routing
Protocol (OLSR)", RFC 3626, October 2003.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC5690] Floyd, S., Arcia, A., Ros, D., and J. Iyengar, "Adding
Acknowledgement Congestion Control to TCP", RFC 5690,
February 2010.
[RFC6297] Welzl, M. and D. Ros, "A Survey of Lower-than-Best-Effort
Transport Protocols", RFC 6297, June 2011.
10.2. Informative References
[Abolhasan]
Abolhasan, M., Hagelstein, B., and J. Wang, "Real-world
performance of current proactive multi-hop mesh
protocols", In Communications, 2009. APCC 2009. 15th Asia-
Pacific Conference on (pp. 44-47). IEEE. , 2009.
[Airjaldi]
Rural Broadband (RBB) Pvt. Ltd., Airjaldi., "Airjaldi
service", Airjaldi web page, www.airjaldi.net , 2015.
[Avonts] Avonts, J., Braem, B., and C. Blondia, "A Questionnaire
based Examination of Community Networks", Proceedings
Wireless and Mobile Computing, Networking and
Communications (WiMob), 2013 IEEE 8th International
Conference on (pp. 8-15) , 2013.
Saldana, et al. Expires January 2, 2016 [Page 31]
Internet-Draft Alternative Network Deployments July 2015
[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 (WiNS-DR '08). ACM, New York, NY, USA,
9-16 , 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, no. 3, pp. 68-73, 2013.
[Castignani_a]
Castignani, G., Loiseau, L., and N. Montavont, "An
Evaluation of IEEE 802.11 Community Networks Deployments",
Information Networking (ICOIN), 2011 International
Conference on , vol., no., pp.498,503, 26-28 , 2011.
[Castignani_b]
Castignani, G., Monetti, J., Montavont, N., Arcia-Moret,
A., Frank, R., and T. Engel, "A Study of Urban IEEE 802.11
Hotspot Networks: Towards a Community Access Network",
Wireless Days (WD), 2013 IFIP , pp.1,8, 13-15 , 2013.
[Castignani_c]
Castignani, G., Arcia-Moret, A., and N. Montavont, "A
study of the discovery process in 802.11 networks",
SIGMOBILE Mob. Comput. Commun. Rev., vol. 15, no. 1, p. 25
, 2011.
[Cerda-Alabern]
Cerda-Alabern, L., "On the topology characterization of
Guifi.net", Proceedings Wireless and Mobile Computing,
Networking and Communications (WiMob), 2012 IEEE 8th
International Conference on (pp. 389-396) , 2012.
[DAE] European Commission, EC., "A Digital Agenda for Europe",
Communication from the Commission of 19 May 2010 to the
European Parliament, the Council, the European Economic
and Social Committee and the Committee of the Regions - A
Digital Agenda for Europe , 2010.
[Everylayer]
former Volo Broadband, Everylayer., "Everylayer",
Everylayer web page, http://www.everylayer.com/ , 2015.
Saldana, et al. Expires January 2, 2016 [Page 32]
Internet-Draft Alternative Network Deployments July 2015
[Flickenger]
Flickenger, R., Okay, S., Pietrosemoli, E., Zennaro, M.,
and C. Fonda, "Very Long Distance Wi-Fi Networks", NSDR
2008, The Second ACM SIGCOMM Workshop on Networked Systems
for Developing Regions. USA, 2008 , 2008.
[FNF] The Free Network Foundation, FNF., "The Free Network
Foundation", The Free Network Foundation web page,
https://thefnf.org/ , 2014.
[Fon] Fon Wireless Limited, Fon., "What is Fon", Fon web page,
https://corp.fon.com/en , 2014.
[Hanbali] Hanbali, A., Altman, E., and P. Nain, "A Survey of TCP
over Ad Hoc Networks", IEEE Commun. Surv. Tutorials, vol.
7, pp. 22-36 , 2005.
[Heer] Heer, T., Hummen, R., Viol, N., Wirtz, H., Gotz, S., and
K. Wehrle, "Collaborative municipal Wi-Fi networks-
challenges and opportunities", Pervasive Computing and
Communications Workshops (PERCOM Workshops), 2010 8th IEEE
International Conference on (pp. 588-593). IEEE. , 2010.
[I-D.ietf-aqm-codel]
Nichols, K., Jacobson, V., McGregor, A., and J. Jana,
"Controlled Delay Active Queue Management", draft-ietf-
aqm-codel-01 (work in progress), April 2015.
[I-D.ietf-aqm-pie]
Pan, R., Natarajan, P., Baker, F., and G. White, "PIE: A
Lightweight Control Scheme To Address the Bufferbloat
Problem", draft-ietf-aqm-pie-01 (work in progress), March
2015.
[Komnios] Komnios, I., Sathiaseelan, A., and J. Crowcroft, "LEDBAT
performance in subpacket regimes", IEEE/IFIP WONS,
Austria, April 2014 , 2014.
[Lampropulos]
Lampropulos, A., Castignani, G., Blanc, A., and N.
Montavont, "Wi2Me: A Mobile Sensing Platform for Wireless
Heterogeneous Networks", 32nd International Conference on
Distributed Computing Systems Workshops (ICDCS Workshops),
2012, pp. 108-113 , 2012.
Saldana, et al. Expires January 2, 2016 [Page 33]
Internet-Draft Alternative Network Deployments July 2015
[Lowenstedt]
Huggler, J., "Lowenstedt Villagers Built Own Fiber Optic
Network", The Telegraph, 03 Jun 2014, available at
http://www.telegraph.co.uk/news/worldnews/europe/
germany/10871150/
German-villagers-set-up-their-own-broadband-network.html ,
2014.
[Mexican] Varma, S., "Lowenstedt Villagers Built Own Fiber Optic
Network", The Times of India, 27 Aug 2013, available at
http://timesofindia.indiatimes.com/world/rest-of-world/
Ignored-by-big-companies-Mexican-village-creates-its-own-
mobile-service/articleshow/22094736.cms , 2013.
[Neumann] Neumann, A., Lopez, E., and L. Navarro, "An evaluation of
bmx6 for community wireless networks", In Wireless and
Mobile Computing, Networking and Communications (WiMob),
2012 IEEE 8th International Conference on (pp. 651-658).
IEEE. , 2012.
[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, Aberdeen , Oct 2012.
[Pietrosemoli]
Pietrosemoli, E., Zennaro, M., and C. Fonda, "Low cost
carrier independent telecommunications infrastructure", In
proc. 4th Global Information Infrastructure and Networking
Symposium, Choroni, Venezuela , 2012.
[Rendon] Rendon, A., Ludena, P., and A. Martinez Fernandez,
"Tecnologias de la Informacion y las Comunicaciones para
zonas rurales Aplicacion a la atencion de salud en paises
en desarrollo", CYTED. Programa Iberoamericano de Ciencia
y Tecnologia para el Desarrollo , 2011.
[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, ExtremeCom '11 ACM, 2011.
[Ros] Ros, D. and M. Welzl, "Assessing LEDBAT's Delay Impact",
Communications Letters, IEEE , vol.17, no.5, pp.1044,1047,
May 2013 , 2013.
Saldana, et al. Expires January 2, 2016 [Page 34]
Internet-Draft Alternative Network Deployments July 2015
[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, North America, 4 , May 2008.
[Sathiaseelan_a]
Sathiaseelan, A., Rotsos, C., Sriram, C., Trossen, D.,
Papadimitriou, P., and J. Crowcroft, "Virtual Public
Networks", In Software Defined Networks (EWSDN), 2013
Second European Workshop on (pp. 1-6). IEEE. , 2013.
[Sathiaseelan_b]
Sathiaseelan, A. and J. Crowcroft, "LCD-Net: Lowest Cost
Denominator Networking", ACM SIGCOMM Computer
Communication Review , Apr 2013.
[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", ACM DEV 5, Proceedings of the Fifth
ACM Symposium on Computing for Development, San Jose , Dec
2014 pp 33-42, 2014.
[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", EUCNC
2014 , 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, 9(6), pp. 881-896 , 2010.
[Suresh] Suresh, L., Schulz-Zander, J., Merz, R., Feldmann, A., and
T. Vazao, "Towards Programmable Enterprise WLANs with
ODIN", In Proceedings of the first workshop on Hot topics
in software defined networks (HotSDN '12). ACM, New York,
NY, USA, 115-120 , 2012.
[Vega] Vega, D., Cerda-Alabern, L., Navarro, L., and R. Meseguer,
"Topology patterns of a community network: Guifi. net.",
Proceedings Wireless and Mobile Computing, Networking and
Communications (WiMob), 2012 IEEE 8th International
Conference on (pp. 612-619) , 2012.
Saldana, et al. Expires January 2, 2016 [Page 35]
Internet-Draft Alternative Network Deployments July 2015
[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, p. 1) , Apr 2007.
[WNDW] Wireless Networking in the Developing World/Core
Contributors, "Wireless Networking in the Developing
World, 3rd Edition", The WNDW Project, available at
wndw.net , 2013.
[WSIS] International Telecommunications Union, ITU, "Declaration
of Principles. Building the Information Society: A global
challenge in the new millenium", World Summit on the
Information Society, 2003, at http://www.itu.int/wsis,
accessed 12 January 2004. , Dec 2013.
[Zennaro] Zennaro, M., Fonda, C., Pietrosemoli, E., Muyepa, A.,
Okay, S., Flickenger, R., and S. Radicella, "On a long
wireless link for rural telemedicine in Malawi", 6th
International Conference on Open Access, Lilongwe, Malawi
, Nov 2008.
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
Saldana, et al. Expires January 2, 2016 [Page 36]
Internet-Draft Alternative Network Deployments July 2015
Bart Braem
iMinds
Gaston Crommenlaan 8 (bus 102)
Gent 9050
Belgium
Phone: +32 3 265 38 64
Email: bart.braem@iminds.be
Ermanno Pietrosemoli
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
Abdus Salam ICTP
Strada Costiera 11
Trieste 34100
Italy
Phone: +39 040 2240 406
Email: mzennaro@ictp.it
Saldana, et al. Expires January 2, 2016 [Page 37]