Patras wireless metropolitan network

Patras Wireless Metropolitan Network (PWMN) is a free (as air), open wifi network community of individuals who all share the same hobby; building and managing wireless networks. Currently PWMN is the dominant wireless network community in Patras, Greece. It has about 80 active members (March 2008) who are the individual node owners of this metropolitan area network and spans over 5 Greek provinces (Achaia, Ileia, Etoloakarnania, Fokida, Corinthia) with links up to 65km. It came into existence after the merging of the two previous dominant wireless networks in Patras, namely Patras Wireless Network and SPN in early 2007. It is a non-profit organization which aims to explore network technologies (basically wireless 802.11) and new computer associated technologies in general.

The Vision

A shared vision of most PWMN members is what we call the open source internet which is a global computer network where its users are at the same time the ISPs, contribute to its development (hardware/software) and is free for everyone to access. The concept is similar to the one followed in the open source software context. The first steps towards this vision is to connect all the already well-established wireless community networks of all the major Greek cities together, thus forming probably the largest (at least area-wise)wifi network ever!.


Project history

PWMN is relatively new (early 2007) but its roots trace back to 2001 when the first wireless network community in Greece was formed: Patras Wireless Network(PWN). The second part of PWMN comes from a totally independent wireless community network, SPN which was being deployed since 2004 in parallel with PWN. In 2006 SPN boasted a faster backbone than PWN, more enthusiastic active members, and a more open/distributed management than the older, more conservative and centrally-managed PWN. In early 2007, most PWN and SPN members decided to overcome their differences and form a totally new network community with members from both networks, following the distributed management system used by SPN, which proved to work better in the community context. Since then PWMN has grown and is now better than ever.


Location

PWMN is, in the most part, based in the city of Patras and its suburbs. Patras' shape and geophysical characteristics (mainly hills) has made it quite difficult to establish wireless links around the whole city. This is because the links require Line of sight. Despite the difficulties, PMWN boasts double or triple-way backbones which together with the dynamic routing protocol used (OSPF), makes the whole network very robust and very fast. Recently, following the shared vision, the network has started to cover a much wider area, aiming at linking all of mainland Greece. This is not a trivial task since most cities are separated by sea, big mountains and large distances. So far, PWMN has managed to establish long distance links up to:
Kyllini in Ileia (straight 65km link from Aroe in Patras) which will shortly be linked with Wireless Amateur Network of Amaliada (WANA)
Nafpaktos in Etoloakarnania (straight 20km from Patras)
Skaloma in Fokida (20km link through Kamares which is linked to Nafpaktos through a 20km link)
Ligia in Derveni, Corinthia (62km link to Nafpaktos)
40km Link to Arakynthos a mountain in Etoloakarnania (the actual name of the place is ellinika) tested, which will later link to WiRAN the Wireless network of Agrinio


Design

The hardware used in PWMN is of-the-shelf 802.11a, 802.11b Wireless devices which operate in 5.4 GHz and 2.4 GHz license-free ISM bands. The actual Computer Hardware used for the Wireless routers can vary from simple Wireless access point to small Single-board computer(SBCs) up to conventional PCs.

The Routing protocol currently used (March 2008) is OSPF, a dynamic routing protocol using a distance vector algorithm. Since the actual network deployment gets more and more meshed with multiple paths from one node to another, the network could benefit by a smarter dynamic routing protocol such as OLSR which is already in use in parts of Athens Wireless Metropolitan Network.

PWMN relies mainly on open source software, and Linux is used to support many PMWN services.

The services used throughout PWMN cover a wide range. One of the main services is the PWMN forum which is the main place for open discussions concerning the network. The PWMN wiki projectaims at creating a big knowledge base for all the challenging aspects of wireless networking. As such it contains various Guides, Tutorials, Member's own designs and even networking equipment reviews. PWMN relies heavily on the WiND project to create a map of the wireless nodes and links using actual terrain info. PWMN users prefer to use IRC for their instant messaging needs; the IRC servers throughout the network are connected to a broader network of IRC servers (HWN:Hellenic Wireless Network) which serve all of the Greek Wireless Communities. There are plenty more services like Game Server, File sharing, VOIP, VPN, DNS, Network monitoring and plenty others.

Athens Wireless Metropolitan Network

Founded on 2002 in Athens Greece, Athens Wireless Metropolitan Network (AWMN) is a grassroot wireless community, taking advantage of new, state of the art wireless technologies, to connect people and services. Its members are node owners, comprising the Athens metropolitan area network, which is open to everyone who wants to participate. More than 2380 members are already connected and more than 8,000 people have stated their intention to connect in the near future (as of September, 2008).

A.W.M.N. aims to promote wireless communications as well as bidirectional broadband digital telecommunication services to the general public as a non-profit activity, in cooperation with educational institutions, state authorities and other grassroot wireless communities in Greece.

Its aims include:
To establish, develop and maintain a community wireless network connecting people and services.
To develop technologies based on wireless and digital telecommunications
To train people in the usage of wireless and digital telecommunications.
To promote and encourage volunteerism and active participation

Cultural and Geographical Context

The network began in Athens, the capital of Greece but its activities are not limited to there. It covers a geographical area (110 km from North to South and 85km from West to East) whose southern most point is Palaia Epidavros (Epidaurus) and whose northern most point is the town of Nea Artaki on the island of Euboea.The extension of the network allows isolated areas with poor technological infrastructure to connect with the Athens network, thus allowing access to the services provided by the main network. Already the islands of Euboea, Aegina, Salamina and the regions surrounding Athens have connected to the network. In anticipation of connecting to AWMN, small wireless ‘islets’ have been created in other cities and on other islands where AWMN has contributed to the technical know-how and equipment. Recently the island of Euboea connected with AWMN and the next stage will be the connection of the wireless ‘islets’ located in Corinth, Lamia (city) and Volos. For wireless ‘islets’ and communities for which direct connection to the wireless system is impossible, specially chosen points have been chosen which, through the use of conventional technology (fast ADSL or SDSL lines), connect to high speed lines with limited services (VoIP, http browsing). There are also plans to reach even more remote cities of Greece such as Patras.


Project History

AWMN’s foundation as a community dates back to 2002. Due to the tremendous problems with broadband services in Greece in 2002 the number of broadband services available to home users was extremely limited. It was mainly due to this problem that AWMN was founded as an alternative broadband network, which allowed its users to experience real broadband services. However after a short period from its “birth” AWMN started to change. An increasing number of people started to have an interest in the network, expressing their interest in joining this project. Very soon the number of network nodes started to grow exponentially, and the network’s character changed from an alternative telecom network to a social network of people based on their interest in the IT/Telecom sector.


Community

Due to the nature of the AWMN it can be considered a network of people for the people. Within the AWMN community personal relationships play a very active role in the network development encouraging the members of the network to have a more active role in the community’s social life. From the start of the project, care was taken to found the non-profit AWMN association and to build on a sound basis. The association with over 200 active members comprises the official face of the network and coordinates the working groups. Membership to the network is open to all. Not all members of the network are obliged to become members of the association. However, they are obliged to accept responsibility for the smooth running of their node and follow the basic rules of the community (this forms an in informal criterion of their selection for connection to other nodes).

The network members form a mosaic of people of varying ages and high educational background which, includes IT and telecommunications professionals, radio amateurs, IT students and technology enthusiasts. All members are driven by a strong community spirit and contribute on a voluntary basis.

Technological Basis

Technology-wise, AWMN makes extensive use of the IEEE 802.11x set of standards and operates on the 2.4GHz and 5.4GHz license-free ISM frequency bands. Over the last few years A.W.M.N. has tested (and later used in production environments) equipment from a huge variety of vendors.

The routing protocol used by the network is BGP. Strives have been made towards new, more adaptive and experimental protocols such as OLSR and many members of the AWMN community have contributed feedback and code to many Linux routing projects.

Homemaking of equipment is encouraged; a great number of workshops have been held in order for members to become familiar with constructing their own aerials and cables. In addition, the community regularly organizes seminars in order to educate aspiring network administrators on wireless technology, protocols, routing and Linux, in real conditions of a large-scale network.

AWMN relies heavily on Free Libre/Open-Source Software. GNU/Linux (or other free Unix variants) is the operating system of choice for most servers actively serving the network, and other FL/OSS has made the ever-increasing number of services available, possible.


Solutions and Services

The problem that AWMN came to solve in the greater area of Athens was that of broadband telecommunication among the participants of the network. To start of with the AWMN forum came to life where all the community members would exchange ideas, arrange meetings, arrange wireless links and discuss various points of interest. Nowhere days the services provided by the network have evolved to full a featured internal VoIP network, game servers, file sharing services, hundreds of users/nodes webpages, network statistics services, routing, network monitoring, weather stations, VPN servers and just about anything and any service that someone would come across on the Internet.

As a highlight we should mention the WiND project. As a large-scale network and community, AWMN has the need for a central management tool for displaying important nodes details. WiND (Wireless Nodes Database) is a Web Application targeted at Wireless Community Networks, such AWMN. It has been created by members of AWMN. WiND provides a front-end interface to a database where various information on wireless network nodes can be stored, such as position details, DNS information, IP addressing and a list of provided network services.

Melbourne Wireless

Melbourne Wireless is a non-profit project to develop a community wireless network in Melbourne and end recurrent telco fees. The project uses widely-available, license-free technology to create a free, locally-owned wireless backbone.

This metropolitan area network is detailed well on the organisation's website, which features dynamic mapping systems to show the current development of the network, and a wiki is used for collaboration on technical documents.

Melbourne Wireless made significant contributions on the regulation and future of wireless broadband technologies, as well as the legality of community wireless networks within Australia during 2002

Wireless Community Network

Wireless community networks or wireless community projects are the organizations that attempt to take a grassroots approach to providing a viable alternative to municipal wireless networks for consumers.

Because of evolving technology and locales, there are at least four different types of solutions:
Cluster: Advocacy groups which simply encourage sharing of unmetered internet bandwidth via Wi-Fi, may also index nodes, suggest uniform SSID (for low-quality roaming), supply equipment, dns services, etc.
Mesh: Technology groups which coordinate building a mesh network to provide Wi-Fi access to the internet
WISP: A mesh that forwards all traffic back to consolidated link aggregation point(s) that have centralized access to the internet
WUG: A wireless user group run by wireless enthusiasts. An open network not used for the reselling of internet. Running a combination of various off the shelf WIFI hardware running in the license free ISM bands 2.4 GHz/5.8 GHz

Certain countries regulate the selling of internet access, requiring a license to sell internet access over a wireless network. In South Africa it is regulated by ICASA They require that WISP's apply for a VANS or ECNS/ECS license before being allowed to resell internet access over a wireless link. The cluster and mesh approaches are more common but rely primarily on the sharing of unmetered residential and business DSL and cable Internet. This sort of usage might be non-compliant with the Terms of Service (ToS) of the typical local providers that deliver their service via the consumer phone and cable duopoly. Wireless community network sometimes advocate complete freedom from censorship, and this position may be at odds with the Acceptable Use Policies of some commercial services used. Some ISPs do allow sharing or reselling of bandwidth.

History

These projects are in many senses an evolution of amateur radio, and more specifically packet radio, as well as an outgrowth of the free software community (which in itself substantially overlaps with amateur radio). The key to using standard wireless networking devices designed for short-range use for multi-kilometre Long Range Wi-Fi linkups is the use of high-gain directional antennas. Rather than purchasing commercially available units, such groups sometimes advocate homebuilt antenna construction. Examples include the cantenna, which is typically constructed from a Pringles potato chip can, and RONJA, an optical link that can be made from a smoke flue and LEDs, with circuitry and instructions released under the GFDL. As with other wireless mesh networks, three distinct generations of mesh networks are used in wireless community networks. In particular, in the 2004 timeframe, some mesh projects suffered poor performance when scaled up.

Organization

Organizationally, a wireless community network requires either a set of affordable commercial technical solutions or a critical mass of hobbyists willing to tinker to maintain operations. Mesh networks require that a high level of community participation and commitment be maintained for the network to be viable. The mesh approach currently requires uniform equipment. One market-driven aspect of the mesh approach is that users who receive a weak mesh signal can often convert it to a strong signal by obtaining and operating a repeater node, thus extending the mesh network.

Such volunteer organizations focusing in technology that is rapidly advancing sometimes have schisms and mergers. The Wi-Fi service provided by such groups is usually free and without the stigma of piggybacking (internet access). An alternative to the voluntary model is to use a co-operative structure

Wireless Networking

FIGURE SHOWS::RouterBoard 112 with U.FL-RSMA pigtail and R52 miniPCI Wi-Fi card

Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes is implemented without the use of wires. Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves, for the carrier and this implementation usually takes place at the physical level or "layer" of the network.

Types::

Wireless PAN

Wireless Personal Area Network (WPAN) is a type of wireless network that interconnects devices within a relatively small area, generally within reach of a person. For example, Bluetooth provides a WPAN for interconnecting a headset to a laptop. ZigBee also supports WPAN applications.


Wireless LAN

Wireless Local Area Network (WLAN) is similar to other wireless devices and uses radio instead of wires to transmit data back and forth between computers on the same network. Wireless LANs are standardized under the IEEE 802.11 series.
 
Screenshots of Wi-Fi Network connections in Microsoft Windows. Figure 1, left, shows that not all networks are encrypted (locked unless you have the code, or key), which means anyone in range can access them. Figures 2 and figur 3, middle and right, however, show that many networks are encrypted.
Wi-Fi: Wi-Fi is a commonly used wireless network in computer systems to enable connection to the internet or other machines that have Wi-Fi functionalities. Wi-Fi networks broadcast radio waves that can be picked up by Wi-Fi receivers attached to different computers or mobile phones.
Fixed Wireless Data: Fixed wireless data is a type of wireless data network that can be used to connect two or more buildings together to extend or share the network bandwidth without physically wiring the buildings together.

Wireless MAN

Wireless Metropolitan area networks are a type of wireless network that connects several Wireless LANs.
WiMAX is the term used to refer to wireless MANs and is covered in IEEE 802.16d/802.16e.


Mobile devices networks
Global System for Mobile Communications (GSM): The GSM network is divided into three major systems: the switching system, the base station system, and the operation and support system. The cell phone connects to the base system station which then connects to the operation and support station; it then connects to the switching station where the call is transferred to where it needs to go. GSM is the most common standard and is used for a majority of cell phones.
Personal Communications Service (PCS): PCS is a radio band that can be used by mobile phones in North America. Sprint happened to be the first service to set up a PCS.
D-AMPS: D-AMPS, which stands for Digital Advanced Mobile Phone Service, is an upgraded version of AMPS but it is being phased out due to advancement in technology. The newer GSM networks are replacing the older system.


Uses
 
An embedded RouterBoard 112 with U.FL-RSMA pigtail and R52 mini PCI Wi-Fi card widely used by wireless Internet service providers (WISPs) in the Czech Republic.

Wireless networks have had a significant impact on the world as far back as World War II. Through the use of wireless networks, information could be sent overseas or behind enemy lines easily, efficiently and more reliably. Since then, wireless networks have continued to develop and their uses have grown significantly. Cellular phones are part of huge wireless network systems. People use these phones daily to communicate with one another. Sending information overseas is possible through wireless network systems using satellites and other signals to communicate across the world. Emergency services such as the police department utilize wireless networks to communicate important information quickly. People and businesses use wireless networks to send and share data quickly whether it be in a small office building or across the world.

Another important use for wireless networks is as an inexpensive and rapid way to be connected to the Internet in countries and regions where the telecom infrastructure is poor or there is a lack of resources, as in most developing countries.

Compatibility issues also arise when dealing with wireless networks. Different components not made by the same company may not work together, or might require extra work to fix these issues. Wireless networks are typically slower than those that are directly connected through an Ethernet cable.

A wireless network is more vulnerable, because anyone can try to break into a network broadcasting a signal. Many networks offer WEP - Wired Equivalent Privacy - security systems which have been found to be vulnerable to intrusion. Though WEP does block some intruders, the security problems have caused some businesses to stick with wired networks until security can be improved. Another type of security for wireless networks is WPA - Wi-Fi Protected Access. WPA provides more security to wireless networks than a WEP security set up. The use of firewalls will help with security breaches which can help to fix security problems in some wireless networks that are more vulnerable.


Environmental concerns and health hazard

In recent times, there have been increased concerns and research linking usage of wireless communications with poor concentration, memory loss, nausea, premature senility and even cancer. Questions of safety have been raised, citing that long term exposure to electromagnetic radiation of the sort emitted by wireless networks may someday prove to be dangerous