Patras Wireless Network

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PWN logo

Patras Wireless Network (PWN) is, historically, the first city-wide, wireless community network in Greece. It is run and maintained by the users of the network. It serves 150 people, covering a mountainous area of 60 $k m 2$ .

1 Introduction
2 Mission
3 History
4 Architecture and topology
- 4.1 Connection to the Outer World
5 Projects
6 Future plans
7 See also
8 External links

[edit] Introduction

Patras Wireless Network was established in 2001 after a company of 4 friends put together the money to purchase an Orinoco Wireless Access Point. The AP was installed on a TV tower in Aroe which has a vantage point of the whole city of Patras. The first private, city-wide wireless connection in Greece was established then.

Claim to fame for PWN was that members on the network solved the hidden node problem, by designing and implementing the Wireless Central Coordinated Protocol (WiCCP), a protocol booster for 802.11b DCF based wireless networks, that provides cyclic token-passing medium access, and scheduled allocation of the available network resources, eliminating the hidden node problem.

[edit] Mission

The original mission of PWN was mostly experimental, focused on using off-the-shelf wireless devices or PCs operating under Linux, to establish 802.11b links over the city of Patras. The main effort of the founders was to evaluate the performance of the TCP/IP protocol suite, over error-prone wireless links, while applying several protocol boosters at the link layer.

[edit] History

Overview of the city of Patras at night

[edit] Reasons for deployment

The initial reason for the network deployment was to test the 802.11b protocol in the rural environment of Patras. Later on, as the network became more stable, the founders decided they could extend the functionality to network themselves and some friends together, overcomming the innability of the state-run telecommunications company of Greece,OTE, to deliver high-speed internet access in the city of Patras.

[edit] The people behind the network

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[edit] Form of management

There is no "management" per se, of the network. The state of the network is supposed to be a free-flow, anarchical state, where ordinary citizens are not binded by the short-commings of the Greek telecom company and are able to organise something on their own, without asking or wanting private or state assistance and sponsoring.

[edit] Funding and Equipment

Funding is mostly provided by the users of the network, by either rallying up money for purchasing of equipment or by equipment donation.

[edit] Rules of Operation

In the early days of operation of the network, traffic between the two large segments that comprised the network, went though a single, central wireless access point, located on the TV tower of the Greek television Network, in Aroe. That created a huge problem during night-time. Night time is mainly the heavy-usage hours of the network. So, the following rules where put in place, in order to accommodate smooth usage by all users:

Every day, 10 p.m. to 2 a.m., was designated as "gaming hours". All file transfers must stop between those hours.
File transfers must be limited to 50 kB/s
Violators of the above policies, will be given a 24 hour ban from the network
Repeat violators will be permanetely banned.

[edit] Architecture and topology

The city of Patras is built around a hill, Alsos Hill (100 m alt.), the highest point in the city. It is also the location of the central Access Point and the reason for the uniqueness in the network design. The network started with a "star" topology. All clients or access point were connected through the main Access Point in Aroe hill. This topology is severely flawed, mainly due to the hidden node problem, so the network moved to a bus-ring topology, providing more reliability to the users.

2D topographical structure of the network (from nodedb)

[edit] Connection to the Outer World

The network does not have an official connection to the global internet. Some members of the network share their aDSL lines by setting up HTTP proxies and using some form of bandwidth throttle in order to distribute their bandwidth on the network.

[edit] Projects

PatrasWireless is a very active network. The community has developed various hardware or software projects. One of the first and most promising projects is the design and implementation of the Wireless Central Coordinated Protocol (WiCCP), a protocol booster for 802.11b DCF based wireless networks, that provides cyclic token-passing medium access, and scheduled allocation of the available network resources, eliminating the hidden node problem.

Furthermore, other community members started project WiFiAdmin. Wifiadmin is a PHP web environment for the administration of the open source (*nix) wifi node. It provides an interface for wireless tools and other common wifi linux/BSD drivers, while keeping statistical data on the node.

Hardware projects include the guide on the rooftop Access Point. It's an attempt to write a guide on how to safely power a rooftop Wireless Access Point-node from a long distance (over 500 m) and turn it into a robust all-weather installation, that can stay unattended for days on end.

[edit] Future plans

Some users were rather inventive

Future plans include increasing the availability of the network, by interconnecting the access points in a mesh manner, in order to allow for truly dynamic routing between each access point.

Currently, the network members are also trying to put together a representative team that will get in contact with the city councel of Patras or the University of Patras in order to obtain some form of connectivity with the rest of the world.