[gaia] draft-manyfolks: loose definition of "traditional network"
"Jose Saldana" <jsaldana@unizar.es> Mon, 16 February 2015 16:36 UTC
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From: Jose Saldana <jsaldana@unizar.es>
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Date: Mon, 16 Feb 2015 17:36:45 +0100
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Cc: 'Matthew Ford' <ford@isoc.org>
Subject: [gaia] draft-manyfolks: loose definition of "traditional network"
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Hi all. I need your opinion (and your help) about this: Mat suggests to include a loose definition of a "traditional network", in order to compare the alternatives with it. > > 2. Classification > > > > 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. > > > > This classification is agnostic from the technical point of view. > > Technology in this case must be taken as implementation. Moreover, > > many of these networks are implemented in a way that several > > technologies (Ad-Hoc Wi-Fi, Infrastructure Wi-Fi, Optical Fiber, > > IPv4, IPv6, RFC1918, OLSR, BMX6, etc.) coexist. > > I wonder if it might be helpful for the reader to include a loose definition of > 'traditional' network, to compare these alternatives with. What is the defining > characteristic that makes these alternatives different? What about something like this?: In this document we will use the term "traditional networks" to denote those where a telecommunications company deploys an infrastructure and offers it to the end users, who pay a subscription fee to be connected and make use of it. The company is usually the owner and the manager of the infrastructure. Thanks in advance, Jose > -----Mensaje original----- > De: Matthew Ford [mailto:ford@isoc.org] > Enviado el: viernes, 06 de febrero de 2015 12:57 > Para: Jose Saldana > CC: gaia@irtf.org > Asunto: Re: [gaia] New Version Notification for draft-manyfolks-gaia-community- > networks-02.txt > > Hi Jose, > > > On 21 Jan 2015, at 17:21, Jose Saldana <jsaldana@unizar.es> wrote: > > > > Hi all, > > > > We have just updated (and uploaded) a new version of the "Manyfolks draft": > Alternative Network Deployments. Taxonomy and characterization. > > > > URL: http://www.ietf.org/internet-drafts/draft-manyfolks-gaia-community- > networks-02.txt > > > > 8< snip >8 > > > > > If you want to have a look to it and send your comments, it would be fine. > > > > Sure! > > A general observation: I find the taxonomical aspect a bit lacking at present. I would > like to have a sharper identification of the characteristics of identified alternative > network types that distinguishes them. Is it the commercial model? Is it the > centralisation or decentralisation of network management? The descriptions are fine > as far as they go, but if there's something unique about the different types that > clearly distinguishes them it would help to call that out better. Maybe a matrix of the > various identified types of network and some of the important characteristics would > be appropriate. > > Some more detailed comments inline: > > > > > > > > > Global Access to the Internet for All J. Saldana, Ed. > > Internet-Draft University of Zaragoza > > Intended status: Informational A. Arcia-Moret > > Expires: July 25, 2015 Universidad de Los Andes > > B. Braem > > iMinds > > L. Navarro > > U. Politecnica Catalunya > > E. Pietrosemoli > > ICTP > > C. Rey-Moreno > > University of the Western Cape > > A. Sathiaseelan > > University of Cambridge > > M. Zennaro > > Abdus Salam ICTP > > January 21, 2015 > > > > Please review: https://www.rfc-editor.org/policy.html#policy.authlist > > I suggest you may want to consider identifying a single Editor and moving other > authors to a Contributing authors section. > > > > > Alternative Network Deployments. Taxonomy and characterization > > Given how much of the document is dedicated to discussing the technologies > employed in alternative networks, and their architecture, I wonder about extending > the title, e.g. > > "Alternative Networks: Taxonomy, characterization, technologies and architectures" > > > draft-manyfolks-gaia-community-networks-02 > > > > Abstract > > > > This document presents a taxonomy of "Alternative Network > > deployments", and a set of definitions and shared characteristics. > > It also discusses the technologies employed in these network deployments, and their > differing architectural characteristics. > > > This term includes a set of network access models emerged in the last > > s/models emerged/models that have emerged/ > > > 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 the network > > s/deploys/deploys or leases/ > > > infrastructure for connecting the users, who pay for it. > > Maybe s/who pay for it/who pay a subscription fee to be connected and make use > of it/ > > > Several initiatives throughout the world have built large scale > > networks that are alternative to the traditional network operator > > deployments using predominately wireless technologies (including long > > s/predominately/predominantly > > > 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 such alternate > > network: networks such as 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 > > such as the reluctance, or the impossibility, of network operators to > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 1] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > provide wired and cellular infrastructures to rural/remote areas. In > > these cases, the networks have self sustainable business models that > > provide more localised 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 (public or private) stakeholder, 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 July 25, 2015. > > > > 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 > > publication of this document. Please review these documents > > carefully, as they describe your rights and restrictions with respect > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 2] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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. Requirements Language . . . . . . . . . . . . . . . . . . 5 > > 2. Classification . . . . . . . . . . . . . . . . . . . . . . . 5 > > 2.1. Community Networks . . . . . . . . . . . . . . . . . . . 5 > > 2.1.1. Free Networks . . . . . . . . . . . . . . . . . . . . 6 > > 2.2. Wireless Internet Service Providers WISPs . . . . . . . . 7 > > 2.3. Shared infrastructure model . . . . . . . . . . . . . . . 7 > > 2.4. Crowdshared approaches, led by the people and third party > > stakeholders . . . . . . . . . . . . . . . . . . . . . . 8 > > 2.5. Testbeds for research purposes . . . . . . . . . . . . . 9 > > 3. Scenarios where Alternative Networks are deployed . . . . . . 9 > > 3.1. Digital Divide and Alternative Networks . . . . . . . . . 9 > > 3.2. Urban vs. rural areas . . . . . . . . . . . . . . . . . . 11 > > 4. Technologies employed . . . . . . . . . . . . . . . . . . . . 12 > > 4.1. Wired . . . . . . . . . . . . . . . . . . . . . . . . . . 12 > > 4.2. Wireless . . . . . . . . . . . . . . . . . . . . . . . . 12 > > 4.2.1. Antennas . . . . . . . . . . . . . . . . . . . . . . 13 > > 4.2.2. Link length . . . . . . . . . . . . . . . . . . . . . 14 > > 4.2.2.1. Line-of-Sight . . . . . . . . . . . . . . . . . . 14 > > 4.2.2.2. Transmitted and Received Power . . . . . . . . . 15 > > 4.2.2.3. Medium Access Protocol . . . . . . . . . . . . . 16 > > 4.2.3. Layer 2 . . . . . . . . . . . . . . . . . . . . . . . 16 > > 4.2.3.1. 802.11 (Wi-Fi) . . . . . . . . . . . . . . . . . 16 > > 4.2.3.2. GSM . . . . . . . . . . . . . . . . . . . . . . . 18 > > 4.2.3.3. Dynamic Spectrum . . . . . . . . . . . . . . . . 18 > > 5. Network and architecture issues . . . . . . . . . . . . . . . 20 > > 5.1. Layer 3 . . . . . . . . . . . . . . . . . . . . . . . . . 20 > > 5.1.1. IP addressing . . . . . . . . . . . . . . . . . . . . 20 > > 5.1.2. Routing protocols . . . . . . . . . . . . . . . . . . 20 > > 5.1.2.1. Traditional routing protocols . . . . . . . . . . 21 > > 5.1.2.2. Mesh routing protocols . . . . . . . . . . . . . 21 > > 5.2. Upper layers . . . . . . . . . . . . . . . . . . . . . . 21 > > 5.2.1. Services provided by Alternative Networks . . . . . . 22 > > 5.2.1.1. Intranet services . . . . . . . . . . . . . . . . 22 > > 5.2.1.2. Access to the Internet . . . . . . . . . . . . . 23 > > 5.3. Topology . . . . . . . . . . . . . . . . . . . . . . . . 23 > > 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24 > > 7. Contributing Authors . . . . . . . . . . . . . . . . . . . . 24 > > 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 > > 9. Security Considerations . . . . . . . . . . . . . . . . . . . 25 > > 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 25 > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 3] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 10.1. Normative References . . . . . . . . . . . . . . . . . . 25 > > 10.2. Informative References . . . . . . . . . . . . . . . . . 28 > > Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 > > > > 1. Introduction > > > > Several initiatives throughout the world have built large scale > > networks that are alternative to the traditional network operator > > deployments using predominately wireless technologies (including long > > s/predominately/predominantly > > > 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 such alternate > > network: networks such as 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 localised communication services as > > well as Internet backhaul support 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, > > 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 emerged in the last > > s/models emerged/models that have emerged/ > > > 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 for it. The document is > > Maybe s/who pay for it/who pay a subscription fee to be connected and make use > of it/ > > > 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. > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 4] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 1.1. Requirements Language > > > > The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", > > "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" > in this > > document are to be interpreted as described in RFC 2119 [RFC2119]. > > This document is not on the standards track, so this section is not necessary. Also, > capitalisation of words like CAN and MAY later in the draft is not appropriate. > > > > > 2. Classification > > > > 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. > > > > This classification is agnostic from the technical point of view. > > Technology in this case must be taken as implementation. Moreover, > > many of these networks are implemented in a way that several > > technologies (Ad-Hoc Wi-Fi, Infrastructure Wi-Fi, Optical Fiber, > > IPv4, IPv6, RFC1918, OLSR, BMX6, etc.) coexist. > > I wonder if it might be helpful for the reader to include a loose definition of > 'traditional' network, to compare these alternatives with. What is the defining > characteristic that makes these alternatives different? > > > > > 2.1. Community Networks > > > > 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 agreeing to an open peering agreement. > > Community members directly contribute active network infrastructure > > (not just passive 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. > > > > No need to capitalise CAN. This document is not standards track or normative. This > applies throughout the document, but I'm not going to comment every time. > > > 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. The network CAN be managed by multiple routing > > protocols or network topology management systems. > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 5] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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. A clear example of this kind of Community > > Network is described in [Braem]. These networks are effective in > > enhancing and extending digital Internet rights following a > > participatory model. > > I couldn't parse the final sentence of that para. > > > > > 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 network 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 > > extent of the network 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. > > See earlier comment about providing a definition of traditional ISP. If there are other > defining characteristics, it could help to identify them up front. > > > > > 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. > > > > 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." > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 6] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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. > > > > 2.2. Wireless Internet Service Providers WISPs > > > > WISPs are commercially-operated wireless Internet networks that > > provide Internet and/or Voice Over Internet (VoIP) services. They > > are most common in areas not covered by 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. > > What I miss in this section is some text that talks about why a WISP is able to > succeed where an incumbent or traditional ISP is not. If WISPs are for-profit > enterprises, then why are they able to make a return, or why do incumbents choose > not to? > > > > > Since 2006, the deployment of cloud-managed WISPs has been possible > > I think a sentence defining 'cloud-managed' would be helpful here. > > > with companies like Meraki and later OpenMesh and others. Until > > recently, however, most of these services have been aimed at > > industrialised markets. Everylayer [Everylayer], launched in 2014, > > is the first cloud-managed WISP service aimed at emerging markets. > > > > 2.3. Shared infrastructure model > > > > These networks are owned by individuals but leased out to network > > operators who use them as a low cost medium to reach the underserved > > population. > > > > > > Can you give a more expansive example. Do you mean something like FON (I > guess not as that is described in the next section)? How is this different from an > (M)VNO? > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 7] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 2.4. Crowdshared approaches, led by the people and third party > > stakeholders > > > > 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. The node location exhibits a > > space and time correlation which is the basis to establish a robust > > connectivity model over time. > > I couldn't really parse that last sentence. > > > > > These networks conform to the following approach: the home router > > creates two wireless networks: one of them is normally used by the > > owner, and the other one is public. A small fraction of the > > bandwidth is allocated to the public network, to be employed by any > > user of the service in the immediate area. Some examples are > > described in [PAWS] and [Sathiaseelan_c]. Other 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. > > > > 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 summarised 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. > > > > - 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 > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 8] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > (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. > > > > 2.5. Testbeds for research purposes > > > > 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]. > > This section is kind of amusing to me, given the origins of the Internet. Maybe it is > Comcast, BT, Telefonica et al. that are the 'Alternative Networks'? :) > > > > > 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 > > > > There is no definition for what a developing country represents that > > has been recognized internationally, but the term is generally used > > to describe a nation with a low level of material well-being. In > > this sense, one of the most commonly used classification is the one > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 9] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > by the World Bank, who ranks countries according to their Gross > > National Income (GNI) per Capita: low income, middle income, and high > > income, being those falling within the low and middle income groups > > considered developing economies. 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. Additionally, the Human Development Index, which > > considers not only the GNI but also life expectancy and education, > > has been proposed by the United Nations to rank countries according > > to their well-being and not solely based on economic terms. These > > classifications are used to give strong signals to the international > > community about the need of special concessions in support of these > > countries, implying a correlation between development and increased > > well-being. > > > > 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 organisations" to actively engage to accomplish it > > [WSIS]. > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 10] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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 > > 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 > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 11] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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 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 > > 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 been also 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. > > > > 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]. > > > > 4.2. Wireless > > > > Different wireless technologies [WNDW] can be employed in Alternative > > Network deployments. Below we summarise topics to be considered in > > such deployments: > > > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 12] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 4.2.1. Antennas > > > > Three kinds of antennas are suitable to be used in these networks: > > omnidirectional, directional and high gain 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. > > > > When using an omnidirectional antenna outdoors to provide > > connectivity to a large area, people often select high gain antennas > > located at the highest structure available to extend the coverage. > > In many cases this is counterproductive, since a high gain > > omnidirectional antenna will have a very narrow beamwidth in the > > vertical plane, meaning that clients that are below the plane of the > > antenna will receive a very weak signal (and by the reciprocity > > property of all antennas, the antenna will also receive a feeble > > signal from the client). A moderate gain omnidirectional of about 8 > > to 10 dBi is normally preferable. Higher gain omnidirectional > > antennas are only advisable when the farthest way client is roughly > > in the same plane. > > > > 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]. > > > > 24 to 34 dBi antennas are commercially available at both the > > unlicensed 2.4 GHz and 5 GHz bands, and even higher gain antennas can > > be found in the newer unlicensed bands at 17 GHz and 24 GHz. > > > > 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 at 5 > > GHz. Deploying high gain antennas at both ends will more than > > compensate for the additional free space loss. Furthermore, higher > > frequencies can make do with lower altitude antenna placement since > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 13] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > the Fresnel ellipsoid (the volume around the optical line occuppied > > by radio waves, which should be free from obstacles), is inversely > > proportional to the square root of the frequency. > > > > On the contrary, lower frequencies offer advantages when the line of > > sight is blocked because they can leverage diffraction to reach the > > intended receiver. > > > > It is common to find dual radio Access Points, at two different > > frequency bands. One way of benefiting from this arrangement is to > > attach a directional antenna to the high frequency radio for > > connection to the backbone and an omnidirectional one to the lower > > frequency to provide local access. > > > > 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 polarisation must be used at both ends of any radio > > link. For point-to-point links, some vendors use two radios > > operating at the same frequency but with orthogonal polarisations, > > thus doubling the achievable throughput, and also offering added > > protection to multipath and other transmission impairments. > > > > 4.2.2. 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 path 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. > > > > Another factor to be considered is that the Fresnel zone (the volume > > around the optical line) must be unencumbered from obstacles for the > > maximum signal to be captured at the receiver. The size of the > > Fresnel ellipsoid grows with the distance between the end points and > > with the wavelength of the signal, which in turn is inversely > > proportional to the frequency. > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 14] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > For optimum signal reception the end points must be high enough to > > clear any obstacle in the path and leave extra "elbow room" for the > > Fresnel zone. This can be achieved by using suitable masts at either > > end, or by taking advantage of existing structures or hills. > > > > 4.2.2.2. Transmitted and Received Power > > > > Once a clear radio-electric line of sight (including the Fresnel zone > > clearance) is obtained, one must ascertain that the received power is > > well 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. > > > > The sensitivity of the receiver decreases with the transmission > > speed, so more power is needed at greater transmission speeds. > > > > The received power is determined by the transmitted power, the gain > > of the transmitting and receiving antennas and the propagation loss. > > > > The propagation loss is the sum of the free space loss (proportional > > to the square of the the frequency and the square of the distance), > > plus additional factors like attenuation in the atmosphere by gases > > or meteorological effects (which are strongly frequency dependent), > > multipath and diffraction losses. > > > > Multipath is more pronounced in trajectories over water. If they > > cannot be avoided special countermeasures should be taken. > > > > In order to achieve a given link margin (also called "fade margin"), > > one can: > > > > a) 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) 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. Many countries impose a limit in the combination > > of transmitted power and antenna gain, EIRP (Equivalent Isotropically > > Irradiated Power) which can be different for point-to- point or > > point-to-multipoint links. > > > > c) Reduce the propagation loss, by using a more favorable frequency > > or a shorter path. > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 15] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > d) 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. This step is often done automatically in > > many protocols, in which the transmission speed can be reduced from > > 150 Mbit/s to 6 Mbit/s if the receiver power is not enough to sustain > > the maximum throughput. > > > > 4.2.2.3. Medium Access Protocol > > > > A completely different limiting factor is related to the medium > > access protocol. Wi-Fi was designed for short distance, and the > > transmitter expects the reception of an acknowledgment for each > > transmitted packet in a certain amount of time; if the waiting time > > is exceeded, the packet is retransmitted. This will significantly > > reduce the throughput at long distance, so for long distance > > applications it is better to use a different medium access technique, > > in which the receiver does not wait for an acknowledgement of the > > transited packet. This strategy of TDMA (Time Domain Multiple > > Access) has been adopted by many equipment vendors who offer > > proprietary protocols alongside the standard Wi-Fi in order to > > increase the throughput at longer distances. Low cost equipment > > using TDMA can offer high throughput at distances over 100 > > kilometers. > > > > 4.2.3. Layer 2 > > > > 4.2.3.1. 802.11 (Wi-Fi) > > > > Wireless standards ensure interoperability and usability to those who > > design, deploy and manage wireless networks. The standards used in > > the vast majority of Community Networks come from the IEEE Standard > > Association's IEEE 802 Working Group. > > > > The standard we are most interested in is 802.11 a/b/g/n, > > [IEEE.802-11A.1999], [IEEE.802-11B.1999], [IEEE.802-11G.2003], > > [IEEE.802-11N.2009] as it defines the protocol for Wireless LAN. > > Different 802.11 amendments have been released, as shown in the table > > below, also including their frequencies and approximate ranges. > > > > > > > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 16] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > |802.11| Release | Freq |BWdth | Data Rate per | Approx range (m) | > > |prot | date | (GHz)|(MHz) |stream (Mbit/s) | indoor | outdoor | > > +------+---------+------+------+----------------+--------+----------+ > > | a |Sep 1999 | 5 | 20 | 6,9,12, 18, 24,| 35 | 120 | > > | | | | | 36, 48, 54 | | | > > | b |Sep 1999 | 2.4 | 20 | 1, 2, 5.5, 11 | 35 | 140 | > > | g |Jun 2003 | 2.4 | 20 | 6,9,12, 18, 24,| 38 | 140 | > > | | | | | 36, 48, 54 | | | > > | n |Oct 2009 | 2.4/5| 20 | 7.2, 14.4, 21.7| 70 | 250 | > > | | | | | 28.9, 43.3, | | | > > | | | | | 57.8, 65, 72.2 | | | > > | n |Oct 2009 | 2.4/5| 40 | 15, 30, 45, 60,| 70 | 250 | > > | | | | | 90, 120, | | | > > | | | | | 135, 150 | | | > > | ac |Nov 2011 | 5 | 20 | Up to 87.6 | | | > > | ac |Nov 2011 | 5 | 40 | Up to 200 | | | > > | ac |Nov 2011 | 5 | 80 | Up to 433.3 | | | > > | ac |Nov 2011 | 5 | 160 | Up to 866.7 | | | > > > > In 2012 IEEE issued the 802.11-2012 Standard that consolidates all > > the previous amendments. The document is freely downloadable from > > IEEE Standards [IEEE]. > > > > 4.2.3.1.1. Deployment planning for 802.11 wireless networks > > > > Before packets can be forwarded and routed to the Internet, layers > > one (the physical) and two (the data link) need to be connected. > > Without link local connectivity, network nodes cannot talk to each > > other and route packets. > > > > 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. > > > > When two wireless interfaces are configured to use the same protocol > > on the same radio channel, then they are ready to negotiate data link > > layer connectivity. Each 802.11a/b/g 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. The > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 17] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > wireless interface creates a network with a specified name (called > > the SSID, Service Set IDentifier) and channel, and offers network > > services on it. While in master mode, wireless interfaces manage all > > communications related to the network (authenticating wireless > > clients, handling channel contention, repeating packets, etc.) > > 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. > > They then present any necessary credentials to the master, and if > > those credentials are accepted, they are associated with the master. > > 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 neighbours. Nodes must be > > in range of each other to communicate, and must agree on a network > > name and channel. 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 in monitor > > mode, wireless interfaces transmit no data. This is useful for > > analysing problems on a wireless link or observing spectrum usage in > > the local area. Monitor mode is not used for normal communications. > > > > 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. In a multipoint-to-multipoint mesh, the > > radios all operate in ad-hoc mode so that they can communicate with > > each other directly. Managed mode clients cannot communicate with > > each other directly, so a high repeater site is required in master or > > ad-hoc mode. Ad-hoc is more flexible but has a number of performance > > issues as compared to using the master / managed modes. > > > > 4.2.3.2. GSM > > > > GSM 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 > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 18] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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 WiFi 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 > > 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 > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 19] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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 CPEs are sent before slots destined for > > nearby CPEs. > > > > Base stations are required to have a 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 Client Premises > > Equipment (CPE) devices. The standard also has 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. Network and architecture issues > > > > 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. > > > > Most Community Networks use private IPv4 address ranges, as defined > > by RFC 1918 [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 > > > > 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 islands. > > > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 20] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 5.1.2.1. Traditional routing protocols > > > > The BGP protocol, as defined by RFC 4271 [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 OSPF protocol, > > as defined by RFC 2328 [RFC2328]. > > > > 5.1.2.2. Mesh routing protocols > > > > A large number of Alternative Networks use the OLSR routing protocol > > as defined in RFC 3626 [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 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. > > > > 5.2. Upper layers > > > > From 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 Less than Best Effort (LBE) policy > > for the user and protects the sharer. Achieving LBE behaviour > > requires the appropriate tuning of the well known mechanisms such as > > ECN, or RED, or others more recent AQM mechanisms such as CoDel and > > PIE that aid on keeping low latency RFC 6297 [RFC6297]. > > > > The user traffic should not interfere with the sharer's traffic. > > 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. > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 21] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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 centralise 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. > > > > 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 > > with the different impairments (RFC 3135 [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 RFC 5690 [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. > > > > 5.2.1. Services provided by Alternative Networks > > > > 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. > > > > 5.2.1.1. 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. > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 22] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > - Public video cameras. > > > > - DNS. > > > > - Online games servers. > > > > - Jabber instant messaging. > > > > - IRC chat. > > > > - Weather stations. > > > > - NTP. > > > > - Network monitoring. > > > > - Videoconferencing / streaming. > > > > - Radio streaming. > > > > 5.2.1.2. Access to the Internet > > > > 5.2.1.2.1. 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. > > > > 5.2.1.2.2. 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. > > > > 5.3. Topology > > > > Alternative Networks follow different topology patterns, as studied > > in [Vega]. > > > > 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 July 25, 2015 [Page 23] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > capacity (or gain connection) to the network. Other proposals like > > Virtual Public Networks [Sathiaseelan_a] can also extend the service. > > > > 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]. > > > > 6. Acknowledgements > > > > This work has been partially funded by the CONFINE European > > Commission Project (FP7 - 288535). > > > > 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 Matt Ford and > > s/Matt/Mat/ > > > Arjuna Sathiaseelan for their support and guidance. > > > > 7. Contributing Authors > > > > > > > > > > > > > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 24] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > 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 > > > > 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 > > > > > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 25] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > [IEEE.802-11A.1999] > > "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 - High-speed Physical Layer in > > the 5 GHZ Band", IEEE Standard 802.11a, Sept 1999, > > <http://standards.ieee.org/getieee802/ > > download/802.11a-1999.pdf>. > > > > [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.802-11B.1999] > > "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 - Higher-Speed Physical Layer > > Extension in the 2.4 GHz Band", IEEE Standard 802.11b, > > Sept 1999, <http://standards.ieee.org/getieee802/ > > download/802.11b-1999.pdf>. > > > > [IEEE.802-11G.2003] > > "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 4: Further Higher > > Data Rate Extension in the 2.4 GHz Band", IEEE Standard > > 802.11g, Jun 2003, <http://standards.ieee.org/getieee802/ > > download/802.11g-2003.pdf>. > > > > > > > > > > > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 26] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > [IEEE.802-11N.2009] > > "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: Enhancements for > > Higher Throughput", IEEE Standard 802.11n, Oct 2009, > > <http://standards.ieee.org/getieee802/ > > download/802.11n-2009.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", IE > > EE > > 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. > > > > [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate > > Requirement Levels", BCP 14, RFC 2119, March 1997. > > > > [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. > > > > [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. > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 27] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > [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. > > > > [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. > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 28] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > [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. > > > > [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. > > > > [FNF] The Free Network Foundation, FNF., "The Free Network > > Foundation", The Free Network Foundation web page, > > https://thefnf.org/ , 2014. > > > > [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. > > > > [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. > > > > [IEEE] Institute of Electrical and Electronics Engineers, IEEE, > > "IEEE Standards association", 2012. > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 29] > > Internet-Draft Alternative Network Deployments January 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. > > > > [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. > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 30] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > [Ros] Ros, D. and M. Welzl, "Assessing LEDBAT's Delay Impact", > > Communications Letters, IEEE , vol.17, no.5, pp.1044,1047, > > May 2013 , 2013. > > > > [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. > > > > [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. > > > > [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. > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 31] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > [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 > > Universidad de Los Andes > > Facultad de Ingenieria. Sector La Hechicera > > Merida 5101 > > Venezuela > > > > Phone: +58 274 2402811 > > Email: andres.arcia@ula.ve > > > > > > Bart Braem > > iMinds > > Gaston Crommenlaan 8 (bus 102) > > Gent 9050 > > Belgium > > > > Phone: +32 3 265 38 64 > > Email: bart.braem@iminds.be > > > > > > > > > > > > > > > > > > > > Saldana, et al. Expires July 25, 2015 [Page 32] > > Internet-Draft Alternative Network Deployments January 2015 > > > > > > Leandro Navarro > > U. Politecnica Catalunya > > Jordi Girona, 1-3, D6 > > Barcelona 08034 > > Spain > > > > Phone: +34 934016807 > > Email: leandro@ac.upc.edu > > > > > > Ermanno Pietrosemoli > > ICTP > > Via Beirut 7 > > Trieste 34151 > > Italy > > > > Phone: +39 040 2240 471 > > Email: ermanno@ictp.it > > > > > > Carlos Rey-Moreno > > University of the Western Cape > > Robert Sobukwe road > > Bellville 7535 > > South Africa > > > > Phone: 0027219592562 > > Email: crey-moreno@uwc.ac.za > > > > > > 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 July 25, 2015 [Page 33] > > Mat
- [gaia] draft-manyfolks: loose definition of "trad… Jose Saldana
- Re: [gaia] draft-manyfolks: loose definition of "… Steve Song
- Re: [gaia] draft-manyfolks: loose definition of "… Matthew Ford