Board index Free Unlimited PDF Downloads Free Downloads. Forum 3. Please, help me to find this wireless mesh networking by thomas krag pdf. Thanks!. Wireless Mesh Networking: Low Cost Internet Connectivity. A Test bed for Its Possible Implementation and Community Actions in a Barrio “carenciado”. Thomas Krag And Sebastian Buettrich Wireless Mesh Networking Full - shorl. com/nedovopabrapro.
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Case study: Dharamsala Community Wireless Mesh Network. . Tomas Krag spends his days working with cchanconlidopa.gq, a registered non- profit upload and download byte counts for every physical port can greatly simplify tom needs to be properly attached to the leads from both the ring and the. Today ICT4D-AR is focused on two projects: wireless connectivity using WMN and Wireless. Mesh. Networking. (WMN). In Tom Krag and Sebastian. Wireless Network Project - Download as Word Doc .doc), PDF File .pdf), Text “In a mesh network, the wireless connection extends not only to client computers, such as . Franklin, Tom Wireless Local Area Network .. stands from Tomas Krag and Sebastian Büettrich, who defined it as a “network that employs one.
While some authors [11, 20, 30] with each household composed of up to five adults and seven mention the pertinence of cultural factors, very little is said children, scattered into twelve villages of different sizes. These about how to approach them. Small family clusters of rondavels are this team, e.
These are This mesh network project is following in the footsteps regarded as a symbol of prosperity and also more easily al- of those interventions.
Given the airtime consumption pat- low for caching water into large plastic tanks. However, ter points installed by the government. Women typically as free calls will essentially render the network financially walk up to several kilometers with 20 liters of water on their unsustainable, it was decided by the TA to develop a busi- heads. Very often, the few well-educated people emigrate ness model to charge a low rate for calls to keep the mesh to find work in a more urban area.
Thus income is sent network up and running. The TA proposed charging for home, and for local residents comes mainly from governmen- intra-community calls to enable the network to become fi- tal pension payments. Income can also come from land-use, nancially sustainable, so that a local support team can make mostly subsistence agriculture and small-scale domesticated a living from maintaining, and even expanding, the network.
There is a minimal presence of local busi- Scenarios comprised of different usage and pricing patterns nesses, and these are largely focused on obtaining products were explored in order to find the break-even point of the from the nearest city to resell locally at a much higher price, network .
At this stage, the pricing has not yet been e. The area is also home to a well-known surf spot, with a backpackers situated nearby. The beach is gor- 3. The community-driven mesh network rollout described in These tourists stay at the backpackers that also serves as the this paper has only been completed very recently. An initial headquarters for a local NGO non-governmental organiza- visit of two weeks was made in April to explore feasi- tion that actively tackles health, social, educational and bility of the idea with the TA, followed by a two month visit economic needs in the community.
Only a privileged few spanning June—July , where training of the local sup- of the community residents have access to grid electricity. Repair teams from the city must negotiate bad tom solar power solution. This can take 1. This high clearance vehicle, and can take up to 4 hours with local section provides an overview of the main lessons taken from transport used by community residents. One can find basic the literature, situated with how we have approached them amenities in the city; for example food, tools and stationary together with our community.
Given that the project cur- are easily available, yet specialized electronic or telecommu- rently aims to provide only internal VoIP calls, issues re- nications devices are nowhere to be found and need to be im- garding subsequent Internet access and local content are not ported from bigger cities further afield, e.
African standards , mobile phone coverage is widespread, al- beit spotty in places requiring one to walk up this or that hill 3. This year saw the introduction of 3G in Brewer et al. However, with cumulative experience gained in several countries.
Fur- as stated above, most community members do not have grid thermore, to reduce the inter-cultural gap, two co-authors of electricity domestically, and must walk to a power point and this paper speak the local language as a first language: one pay to charge a phone, e. Firstly, because nity and has lived there ever since, also speaks English, and most of their low-end phones do not support cellular data, more importantly, can help bridge cultural gaps between the and second, because even if they did, people could not af- community and the research team.
Other authors may not mention the origin of an idea, yet still stress the importance 3. Co-design provides a sense of owner- there. We interviewed several people with semi-structured ship to the beneficiaries concerning the project . As stated interviews, and with their answers, together with the results above, the TA has been an active part of the design of the of our previous research in the area and our knowledge of network, especially by proposing households that comply the potential of the technology, we came to the idea of us- with the constraints decided among the different partners, ing the mesh nodes as public phones for providing cheaper following a similar approach to : calls within the community.
This is a risk that we must take, and is around the homestead. Given the hilly terrain where the community is located, the proposed node positioning provided by the community 3. The Partnering with local institutions, especially local gov- locals are intimately familiar with poor GSM coverage in ernments and NGOs, is also considered very important, the area; that it is better on hilltops.
This may or may tioned while simultaneously satisfying local politics, e. Also, here it is often believed that local govern- bile were the only tools available to design the network, as ment representatives benefit only themselves. Regardless, some sources may point out , the installation team would we have established strong partnerships with a local NGO have been surprised at the number of links that appear fea- and the local government, the TA.
Thus, local knowledge played an essential role in up being ten that would be installed for the mesh network designing the mesh topology. So far, they clearly the mechanisms and pricing to charge for the calls in order understand that some form of income is needed to maintain to achieve financially sustainability.
We also expect that the network in the future, because it is they who suggested a TA-endorsed team will manage and operate the network, charging for intranet calls in the first place. This is impor- as in , and this will be discussed in more detail below. Johnson and Roux even consider of team work over any other lesson learned, as this approach it the first factor for success , given the different rates nicely dovetails with local traditions.
Our approach here budget hand-in-hand with the local NGO, plays this role. We also provided more in-depth detail about how all stakeholders in the project. He also has several years things work, especially the electrical power, for them to be of experience with ICT. In addition to the single champion able to make decisions consciously and independently.
One idea, which is also susceptible to that person leaving the member from each homestead, then, received such training area, our approach is more aligned to that of community once the electrical installation was completed. In that train- wireless networks where responsibility is shared out among ing session, the local champion explained, with the help of different users of the network.
We employ a network of Lo- other people in the support team, concepts regarding secu- cal Research Assistants LRAs , based on success with this rity and consumption of battery power.
In addition to this, approach with previous projects [10, 24]. We also do this to further improve the knowledge of potential users, an extra in order to avoid local champion block-out, i. In other words, if the local cham- our first line of trainees. As such, the facing a problem, thus reducing the number of interventions aforementioned co-author is also documenting the entire op- from the local support team of technicians, and from them eration and maintenance of the mesh network, in the local to us.
However, the project is still in too early a cals. To take this approach further, we 3. Upon initial rollout, we were disappointed Many agree on the need to develop local competencies to find that the antennae we purchased did not have the gain as key to a successful intervention [21, 20, 5, 13]. Given attributed on its spec sheet.
We had used the aforemen- the lack of homegrown ICT talent in rural areas , many tioned Radio Mobile tool to verify that community-chosen interventions are carried out by specialists from outside the node sites would work, especially regarding distances of up community, who are expected to transfer the maintenance to 2km between nodes.
This did not go well in the field, to local entrepreneurs  or to staff up from the local public as the antennae were not strong enough. Therefore, we or- administration . The response to the general call was the network after initial installation. We have therefore not encouraging and a team of 4—5 people was waiting to be installed remote monitoring or access on purpose, and are picked up every day over a span of two months, and this keen to encourage the local support team to take credit for was without pay.
If the trainer were English- to hold the batteries, installing and dimensioning solar and speaking, then a translation was done to the local language, storage systems, building the connection panel for the elec- and trainees also had the opportunity to use an interpreter trical installation, configuring and installing the routers, and to ask questions if they were not comfortable with English. Although this may sound relatively easy, it took local languages as far as user interfaces are concerned.
Ad- much effort to apply in practice and often delayed the train- ditionally, for the few administrative tools that are used, e. Furthermore, since it is difficult in developing coun- approaching a national translation team to provide native tries like ours to find such items locally at low cost, we are language support for the open source tools we want to use. Once installed, devices can also suffer from harsh going to be a major barrier to use of the management tools.
Grid electricity in our community is scarce, and Secondly, it comes with an integrated Analog Telephone its unreliability compounded by multi-day outages that oc- Adapter ATA that allows for the provision of telephony cur monthly. To avoid reliance on mains power, all mesh without adding an extra device that would increase the power public phones are powered via deep cycle 12v batteries, consumption. The Mesh Potato address environmental concerns raised by some, e.
In addition, the oper- polluting. Note that in our particular community, we are ating system and the user interface have been designed for loath to use wind turbines, despite the prevalence of strong non-technical users, and it is fairly straightforward to create wind throughout the year, due to the noise generated.
So we placed plastic In order to combat the harsh environment where our net- strips in the antennae to dampen that sound, and are now work is located, mainly due to sand, wind, and rain, addi- sensitive to creating any form of noise pollution. The To handle the wind, poles were fixed to the roof in an systems were intentionally over-dimensioned to allow users umbrella-like shape to limit movement, and an inventive to charge mobile phones, their own and those of other com- constraint also attaches an antenna to the pole.
When the TA gave us the location of the age care of the system. There are currently three nodes pow- nodes, we realized that the network could be made much ered by an off-the-self battery solution with smaller capacity more robust by increasing the number of links, and making that provides electricity solely for a given node. For one of the existing ones stronger, if external antennae were added these, we opted to charge the battery with what we know is to the nodes.
We did the handiwork to add the external an- unreliable mains power, although the mesh node still runs tenna to the Mesh Potato only to realize that the antennae off of the battery. This imported off-the-shelf system has un- a supposedly 9dBi dipole antenna, designed for indoors ac- fortunately proven to be incompatible with rural needs, as tually only performed as a directional one. We managed to after four days of rain and cloud, the solar charged system get end-to-end connectivity by having one link at a time, but simply went down.
The problem would not be so impor- not enough to allow for end-to-end calls. As described above tant if it were not necessary to press a restart button every in Section 3. We also noted that the voltage meter is cently been shipped to the community for the local support constantly on; on our solution, we press a doorbell button team to replace the originals. We need to better understand the 3. These five levels of maintenance. We have condensed these into are behind a battery array at the backpackers that allow for only three levels.
While our Level 0 is similar, and we ex- some nominal number of hours of independence. During the pect users to carry out basic maintenance tasks, Levels 1 installation we realized that if a power outage is longer than and 2 from , consisting of local technicians and more ed- 24 hours, the server goes down. A solution must be found ucated technicians from the nearest city, respectively, are for this, if we want to collect data reliably. Levels 3 and 4 from , where high level The choice of the device to form a mesh network is also support and research activities for improving services are an important factor toward overall success.
Providing that carried out, respectively, are combined to form our Level 2, the device complies with the technology one wants to use, that is expected to be carried out by the Village Telco com- in this case WiFi mesh, there are several factors to consider, munity, where several of the authors are active members.
It including low cost , ease of use  and maintainability is through this online community that a more on-demand distance learning mentioned by some, e. Secondly, ac- place in our project; although only for the researchers and tually co-ordinating and getting to meetings takes consider- local technicians, and not for the users.
For improving main- able time. In ad- sources makes them particularly valuable and also envied dition, to facilitate maintenance, the electrical installation if people feel that some are privileged over others. Co- has been designed and constructed in a modular way, allow- ordinating meetings requires contacting community mem- ing each piece of the system to be disconnected for repair bers by phone, which may not be charged for up to several independently, e.
Alternatively, talking the wiring beneath, and a separate breathable area to house in person can often involve walking great distances. Thus the batteries. The rationale behind the box design has been attending meetings can involve hours of travel.
We find explained to the trainees in depth, including how to change ourselves balancing the economics that constrain our time, fuses and replace them by bigger ones, and the consequences e. Practices in close knit rural main concerns in the DEV literature [7, 4, 11]. In this African communities configure time as polychronic, includ- project, the revenue generated from the calls made in the ing being based around people, rather than based on a lim- network are expected to cover the running expenses and ited abstraction of hours or days.
Investing time in conver- even generate revenue for scaling the network, or can even sation and resolving social issues provides the community be used for other projects that the community prioritizes. That is, the value of time spent communicat- scenarios. However, income generation does not necessarily ing for a close knit rural community differs from the values guarantee sustainability.
In the DEV literature, some also that emerge in societies that have many weak and dynamic stress the importance of institutional sustainability, in order social ties. The social cost of an uninformed, controver- for a given network to continue providing services initially sial or opaque decision about the system is extremely high. Thus, at least a project further .
Indeed there is consensus on the need for rural Africa, we propose that sustained success in WiFi for a smooth transfer of leadership to such a local institu- deployments involves conceptualizing project time scales in tion. In our case, such a transition is not even necessary, local terms.
In that project, the researcher lived locally, co-author resident in the community, although his remuner- and took a participative, ethnographic approach.
Residents ation will eventually depend on the revenue generated by gained considerable experience in addressing technical and the system.
This enabled residents to approach the current the community, to manage the financial aspects of the net- project in a more informed way. That station had been sabotaged by family members in the home- 4. It should be and how we are addressing such concerns with this particu- noted, too, that the prior project also followed on precedents lar project, we now turn to discuss the local cultural factors established by earlier projects, demonstrating the benefit of that we are discovering as more time is spent in the com- having successive projects within a single longitudinal arc.
Thus we sought in negotiating and resolving issues, and this is particularly to train both men and women for this project, and the TA true in our community. Three women appeared in the very first sessions of previous project, buried in bushes out of view, by agreeing the training. This suggests cross-cultural complexities that emerge in implementing, with that greater flexibility in training, such as shorter sessions and for a close-knit rural community, an idea conceived by at more convenient locations, and a more extended train- people external to the community.
We sought to produce ing period might have enabled women to participate more local ownership and stimulate enterprise by framing local consistently. This reflects ways that are, at best, unfamiliar and at worse uncomfort- their recognition that younger people are considerably more able for them. However, is one way in which the community avoids internal conflict it also means that those trained are also less likely to be able and maintains internal cohesion.
Thus, we have found it to enforce rules since the community has a very strong elder difficult in both this and previous projects to progress from authority protocol. We hope that as a group, those trained local expectations that we, as experts, will solve all prob- will act together to supervise use and mitigate against use of lems and fix all breakages. Politicians in our country con- the voice services by the TA at the exclusion of other com- tinue to gain power through promises of work, homes and munity members.
However, we are very aware that although pensions for those who were previously marginalized. The younger people in the community tend to be critical of the dominant narrative in our current society continues to blame TA, they are also reserved in voicing critique and may be all social inequality on the former regime.
Conformist values in 4. We cannot assume that residents will neces- gest that the TA pursues consensus in decision making and sarily perceive volunteers who are trained or homesteads in the community has recognized that the TA attempted to which stations are placed act in cooperative community in- ensure that the infrastructure was available to all.
However, terests. Indeed, community members must manage the jeal- as in all communities, perspectives about who is privileged ousy of others with whom they live when budget-constrained by decisions differ.
So, it is common that people assume the projects are introduced to the community. Although we Headman is amenable to a small token to, say, put forward navigated through this with complete transparency in ev- a person for a job, or assign one of the mesh nodes to a par- ery step we have taken so far, discussing every aspect with ticular homestead.
We are cautious to generalize cases in the TA, for them to communicate or deal with the commu- the literature where leaders influence projects in ways that nity, the aforementioned reasons may create bigger problems do not align with community needs. Certainly, we proceed than the solutions are expected to provide due to this intra- carefully in assuming the TA can enable broad community community jealousy. The other relations within and across the villages, and since they spend village that does not have a public phone did not receive much of life outdoors, they are visible to and familiar with one either, not only for the budget constraints, but also as each other.
Homes are often left unlocked, though small a punishment by the TA for another intra-community is- shops and established informal bars have grilled doors and sue.
Thus, the introduction of the mesh nodes has already barbed wire fences. Some people have reputations for pil- created tensions within the community politics, or boosted fering, including from family members although, generally, those already existing, while at the same time can provide theft locally is spoken about as committed by, or in collabo- negotiating tools to relax them.
Inhabitants 4. Thus, we have acted with sincere respect to local traditions. These scenarios will influence the pricing model s that the In addition, for achieving real emancipation and a sense of TA comes up with, and can strongly influence the usage of ownership, additional steps need to be taken.
For example, the system. Based on that emergent model, we must then considering the community the true owner of the network, design a billing system that allows for the different possibil- with us having to ask for permission for modifying some- ities and is adaptable to the local culture in order to pro- thing, obtaining data or even showing it to our peers.
In vide trustworthy transparency to the operation and usage of other words, we do not consider the network as ours 2. This the network. Furthermore, other issues like privacy, opening respect is based on considering the locals as important as hours of the public phones, and socio-economic impact of the ourselves in this mutually beneficial arrangement; acknowl- network will be analyzed as we collect data from the usage edging and making clear that the community is providing of the network.
Alongside such data, we are also measur- as many benefits to us, and not only in research terms, ing performance terms of QoS, availability and usage with as we are providing to them.
Sometimes in research, just software tools like CDRStats and Nagios with MRTG that by giving something, researchers expect to be able to get have been installed and configured as part of the initial roll- any data they want from an isolated and impoverished com- out.
We have initiated a baseline study with questionnaires munity, without even explaining why the data is important administered by local research assistants, among house- and without considering what people would do just to re- holds. We recently received some questionnaires from the ceive something shiny, new and exciting, like a public Mesh field, and are anxious to being examining the baseline data, Potato. Alongside this, we have also encountered situations that will later be compared against follow-up versions of the in this initial rollout where people expected equipment just questionnaires.
Such methods will be combined with more because they were providing data to us. By acknowledging a narrative ones in order to triangulate quantitative and qual- mutual equality, and engaging in discussions where everyone itative data to better understand the impact of the project. Breaking these barriers model scaling up network, the provision of additional ser- takes time on both sides, especially given the existing power vices like breakout calls, access to the Internet and adding structures and racial clashes that still predominate in this tablets and smartphones seamlessly with a WiFi interface to country.
We fully acknowledge that it is going to be diffi- make calls in the network might also be considered.
How- cult to assess whether this approach is more successful than ever, all future efforts will be driven by, with and for the others, and in our opinion, is still worth trying. This work has been funded by Telkom a rural impoverished community.
The independent BSS as an ad hoc network Firstly, let we say few words about ad hoc network including the definition and them we will describe the independent BSS as an ad hoc network.
In Latin, ad hoc exactly means "for this," further meaning "for this purpose only," and as a result usually temporary. When IEEE A minimum IEEE In figure 1 shows two IBSS. This type of operation is often 18 P a g e referred to as an ad hoc network, for the reason that this type of standard is often formed with no pre-planning, for only as long as the LAN is needed.
Distribution system concepts For some networks, the physical limitations agree on the direct station-to-station distance that may be supported, this distance is sufficient.
For some others networks this distance is not constant, it is dynamic increased reporting is required. Instead of existing competition, a BSS may also form a component of an extended form of network that is built with multiple BSS. The distribution system enables mobile device support by providing the logical services necessary to handle address to destination mapping and seamless integration of multiple BSS.
Figure 8. The IEE Those subsets or substandard are used because Wireless LAN works with different frequency range, signals and some others characteristics that we will describe bellow for each subset.
The 5-GHz frequency band isn't as crowded as the 2. It has a shorter range than This is a very commonly used frequency. Microwave ovens, cordless phones, medical and scientific equipment, as well as Bluetooth devices, all work within the 2. It will be particularly important for companies interested in using Wireless fidelity Wi-Fi phones.
It also operates in the heavily used 2. It may, for example, better distribute traffic loads across access points or allow dynamic adjustments of transmission power to minimize interference. Final ratification is expected in late This is especially important in applications that need low latency and high quality-of-service standards such as voice-over-WLAN.
This standard will deal with mesh networking. It is predicted to be ratified in mid The name of this standard is IEEE standard The first version of this standard, Parameters for wireless communications among portable digital devices including notebook computers, peripherals, cellular telephones, beepers, and consumer electronic devices are familiar and usually used by Bluetooth.
The specification also allows for connection to the Internet. The TG4 version provides data speeds of 20 Kbps or Kbps.
The TG3 version supports data speeds ranging from 11 Mbps to 55 Mbps. Added skin contain the use of up to network devices, dynamic device addressing, support for devices in which latency is critical, full handshaking, security supplies, and power management. There will be 16 channels in the 2. Plans of IEEE are to refine the It addresses the "first-mile and last-mile" connection in wireless metropolitan area networks. Inland this standard is created a platform that enables to build a broadband wireless industry using high-rate systems that install quickly without extensive metropolitan cable infrastructures.
The IEEE It also, includes a medium access control layer MAC that supports multiple physical layer specifications.
The physical layer is optimized for bands from 10 to 66 GHz.