Freifunkblog

The Ninux.org team announced the first “Ninux Day”, a weekend with about and for wireless communities. You will meet software and hardware hackers, geeks, nerds, engineers, artists, the curious and academics. Experts from all over Europe offer technical and social presentations in the area of wireless community networks.

Join the Ninux Days in Rome, Italy, from November 27-29, 2009.

More Info here:

* http://wiki.ninux.org/NinuxDay2009
* http://wiki.ninux.org/NinuxDay2009en (English)
* http://wiki.ninux.org/NinuxDay2009it (Italian)
* Announcement: http://blog.ninux.org/2009/09/03/ninux-day-2009
* Ninux Blog http://blog.ninux.org

[via ZioPRoTo]

This version of the OBAMP protocol, implemented as an OLSR plugin, is a simplified one for Wireless Community Networks, where we assume the nodes to be in fixed positions on the roof of the houses. Protocol features regarding mobility have not been implemented (yet).

To explain how the plugin works consider the scenario in the following figure:

There are 7 routers, where only 5 have the OBAMP plugin working. Router 1 2 and 6 also have an attached HNA network with some hosts.

OBAMP nodes generate OLSR OBAMP_ALIVE messages, these OLSR messages are forwarded in the whole network (also by the nodes that do not understand OBAMP thanks to the OLSR design). Because of the flooding mechanism every OBAMP node has a complete list of all the other OBAMP nodes in the mesh network. Every OBAMP node listens on the UDP port 6226 for OBAMP signalling.

When a OBAMP nodes starts it has 5 timers to periodically start operations:

OBAMP_alive_timer: every obamp node sends alive messages to advertise its presence to the other obamp nodes in the network. In the alive message every nodes states its IP address, and if it has already a tree link or not (we will see later this information is important for the outer tree create procedure).
The OBAMP network must have a member called “Core”, that starts the TREE_CREATE procedure. The core is the node with the smallest IP address. When the list of known OBAMP nodes changes, the Core Election procedure is eventually called.

mesh_create_timer: every obamp node every OBAMP_MESH_CREATE_IVAL evaluates how far the other obamp nodes are and selects a subset of nodes to keep mesh links with. Note that to reduce signalling and to increase scalability, the overylay mesh links are setup only with a subset of the nearest OBAMP nodes. To select the overlay neighbor the OBAMP nodes first calculates the ETX distance of the nearest OBAMP nodes, and the creates overlay mesh links to every node that are far in the range (minETX,minETX+1)

tree_create_timer: the core of the network every OBAMP_TREE_CREATE_IVAL sends a message called TREE_CREATE on its mesh links. The creation of the spanning tree is very similar to the spanning tree protocol. When a TREE_CREATE message is received a OBAMP node enables a tree link with its parent and forwards the TREE_CREATE on the other mesh links. TREE_CREATE messages are generated only by the core and are numbered, so TREE_CREATE received over loops can be discarded.

outer_tree_create_timer: The mesh_create algorithm may create cluster of OBAMP nodes within the network that are disconnected between each other. This happens if there are groups OBAMP nodes that are far from each other. If this happens only the cluster where the Core is present will receive the TREE_CREATE and will receive traffic from the distribution tree. To overcome this problem if in a cluster there are not TREE_CREATE every OBAMP_TREE_CREATE_IVAL the node with the smallest IP in the cluster will make a long mesh link with the nearest node that has at least a tree link. All the necessary information to perform this procedure is diffused in the OBAMP_ALIVE messages.

purge_nodes_timer: checks expire time of various variables, and deletes nodes or tree links in a soft state fashion

The OBAMP nodes will capture the multicast udp traffic from the non-OLSR interfaces, and will forward this traffic encapsulated in the UDP tunnels of the distribution tree. The other OBAMP nodes will forward the traffic in the tree and will decapsulate it on their non-OLSR interfaces. To avoid duplicated packets the data is carried into OBAMP_DATA messages, that are identified by a sequence number, and the OBAMP source node where the traffic has been encapsulated.

In the figure black links represent real radio links, and red links represent overlay mesh links (udp tunnels). Router 1 2 3 and will create a OBAMP cluster, with two mesh links. Router 6 and 7 will create a mesh link between them. Because the mesh_create algorithm does not create a mesh link between the two clusters, the router 6 (supposing it has the smallest IP address in the mesh) will create an outer tree link with Router 3.

So please download the code and use it . If you find bugs please report them to Saverio and in the Sourceforge tracker here: 

http://sourceforge.net/tracker/?atid=681702&group_id=117612&func=browse

Thanks for this great result of the summer. Special thanks also to Nino from ninux.org who was the mentor for this projet.

Links

* http://zioproto.ninux.org/wordpress/2009/08/31/olsrd-obamp-plugin/
* http://gredler.at/hg/olsrd/rev/8e7887c1247f
* http://olsr.org
* http://blog.freifunk.net
* http://ninux.org

Another great series of interviews I filmed with Saverio from Ninux.org during the Wireless Community Weekend. Interviews with core contributors to the global Freifunk community:

* Kloschi from Leipzig about the future of Freifunk

* Bruno about the Horst tool developer

* Elektra from Berlin about the B.A.T.M.A.N. routing protocol and the goals of the developers.

Wireless Community Weekend 2008 Highlights from Saverio Proto on Vimeo.

Links:

* http://ninux.org
* http://leipzig.freifunk.net
* http://subsignal.org
* http://open-mesh.org
* http://perspektiv89.com
* http://wiki.freifunk.net/Wireless_Community_Weekend_2008

I just found an interview that I filmed during the Wireless Community Weekend 2008 online. The interview was done by Saverio from Ninux.org with Kloschi and Tetzlav from Leipzig and gives us a few insights where Freifunk is heading. Enjoy!

Wireless Community Weekend 2008: Interview with kloschi at C-Base Berlin from Saverio Proto on Vimeo.

An update on one of our Google summer of code projects: Service Discovery for Freimap. Stefano Pilla from Ninux.org is working on the project. We have widened the project a bit. He is now also working on porting freimap to IDE like Netbeans. This will make it easier in the future to implement new graphic map views.

Service Discovery works fine and at the moment Stefano is testing a prototype and working already on documentation. During the project he got in touch with the creator of JmDNS, Rick Blair. JmDNS is an implementation of mdns for Java. He also started an exchange with the creator of JXMapKit (SwingLabs - Josh) that is the new kind of map for freimap that we want to use with Openstreetmap.

screenshot of the "new freimap"

An important mentor for this project is Alx Morlang from Freifunk in Berlin. Thank you! And our friends from Ninux namely - Saverio, Claudio and all of the team. Service Discovery will be tested first in the freifunk ninux network in Rome during the upcoming weeks with mdns.

screenshot of the "new freimap"

Saverio from the Italian Ninux community has now published a video interview Daniel Paufler and I conducted with them at the Wireless Community Weekend in Berlin. Thank you very much for the great montaggio! It is real fun to watch!

Direct Link: http://www.vimeo.com/1052320

In Berlin, at C-Base, people from wireless communities all around Europe meet to share ideas and experiences. See this interview by Mario Behling with free networks activists from Ninux.org and Freifunk.net

The Freifunk Wireless Community Weekend 2008 is over. I had a fantastic time meeting so many people pushing the idea of free networks to new hights. The interest in free wireless was overwhelming and we probably had more than double the number of the 51 visitors who put their names on the participants list. Many developers were taking part. We saw presentations about OpenWRT, B.A.T.M.A.N., the HorstTool, mikroFM, OpenHardware and the Luci-Interface for Freifunk networks. Receiving questions about "free networks and the implications of the law" regularly, we were extremely pleased that Reto Mantz recently published a doctoral thesis about this subject and held a presentation at the WCW (slides now available).

Besides German communities we were very happy to meet many friends from other countries like www.guifi.net from Catalunia, Spain, Sergey Yugov from Russia, Jesper Svarre with 28 people from Denmark and our friends from the Rome community ninux.org.

Together with the help of Italian and German Freifunkers Saverio and me made tons of interviews. Be sure it will not take two years this time to see them online ;-) Get a little taste of the WCW2008 with the first of a series of videos already published by our Italian friends.

Per ora vi lascio con questo breve video, che mostra qualche immagine della domenicale del Wireless Community Weekend. Molto presto verranno pubblicate le interviste. (http://blog.ninux.org/2008/05/05/lultima-sera-al-wcw2008/)

Direct Link: http://www.youtube.com/watch?v=gGZcH49j4hw

The countdown for the Freifunk Wireless Community Weekend 2008 conference is running and cven is haevily working on the final preparation.

As of now we have 48 people who have put their name on the participants list on the wiki at http://wiki.freifunk.net/WCW08:participants and many more who have confirmed their participation to us directly. People are joining us in the upcoming days from Freifunk communities from all over Germany and from communities in other countries. Our friends from Italy will be represented by the two well known free wireless evangelists Nino and Saverio from ninux.org and we expect Jesper Svarre from Denmark with a group of 25 people from the Association of Computer Professionals.

The WCW is a self organized conference and community gathering. We will have a community track with communities presenting themselves, e.g. from Bastian from the Weimar Freifunkers and from Keks from the community in Berlin North-East.

On the other side there will be technical talks from developers of OpenWRT, the B.A.T.M.A.N. routing protocol developers Marek Lindner and Simon Wunderlich; Thomas Hirsch - the developer of the freimap and a presentation of sven-ola - the main developer of the Freifunk Firmware,

Further panels cover subjects like Web 2.0 in the Freifunk Universe (by me, Mario Behling) or Open Networks and the current law by Dr. Reto Mantz, who has recently published a book on "Offene Netze und Recht",

Many opportunities to meet with some of the most exciting people in the international freifunk sphere! Open Mesh advocat Electra will take part in the WCW and after returning from the Open Tech Summit in Taiwan Juergen Neumann will present the latest advancements on Open Wireless Hardware. 

Last but not least we are happy to welcome participants from the academic scene coming from the TU Berlin and the Fraunhofer FOKUS Institute.

Join us at the Freifunki Wireless Community Weekend in Berlin from May 2-4! Check out the latest updates on http://wiki.freifunk.net/Wireless_Community_Weekend_2008

Some fantastic work was done during the last days working with some great folks to get an application for freifunk networks for the Google Summer of Code out. Our goal is to get new students excited about the idea of free networks and to join us in the development process and contribute code. We have formed an international group to get this application done. Besides talking to our developers in Germany I have been busily speaking to ninux.org from Italy, guifi.net from Spain and France Wireless in order to recruit our most talented and active developers as mentors for the programme. Not everyone was able to give me a "yes" yet, but we have formed a great team to start off and we are happy to welcome even more prospective mentors from other free wireless networks from around the world.

Our starting team of mentors is:

• Sven-Ola Tücke (http://ff-firmware.sf.net, Freifunk Firmware)
• Alexander Morlang (Alx, p2p in freifunk networks, Fraunhofer, Germany)
• Thomas Hirsch (freimap, Fraunhofer, Germany)
• Felix Fietkau (OpenWRT, Europe)
• Frithjof Hammer (Freifunk BNO, Germany)
• Harald Schioeberg (t-labs, Germany)
• Ramon Navarro Bosch (Guifi.net, Spain, former GSoC Plone student)
• Xavi Martinez (Guifi.net, Spain)
• Aaron Kaplan (OLSR.org, Austria)
• Francesco Saverio Proto (ninux.org, Italy)
• Mikolas Bingemer (Freifunk-Hannover.de, Germany, head of Software development of medium sized enterprise)
• Jo-Philipp Wich (leipzig.freifunk.net, Freifunk Leipzig Firmware, Germany)
• Andrea Detti is full researcher and adjoined Professor at the School of Telecommunications Engineering of the University of Rome "Tor Vergata" (Italy)

The backup organization administrator is Mario Behling (me), (Freifunkblog, perspektive89.com, Germany)

My idea is that we would have mentors for students who would maybe even be able to meet them locally. As we find already more than 170 free wireless communities worldwide on the global freifunk newswire, there is a chance we could do this in a lot of cases.

Freifunk serves as an umbrella for all the local projects here. We use the Freifunk-Wiki for our coordination. We started to collect ideas for possible student projects here already as well. Currently there are:

• Multimedia Streaming in Mesh Networks / Porting Obamp to C++
• Passive + Active Measurement in Mesh Networks / Porting OpenIMP probes to OpenWRT
• Traffic Flow Visualization / IPFIX DataSource for freimap
• Mesh Node Status Monitoring / SNMP DataSource for freimap
• Service Discovery in Mesh Networks / Avahi DataSource for freimap
• Service Control Module for freimap
• Topology visualization / B.A.T.M.A.N and olsrd routing decision recovery for freimap
• Database output for freimap
• Antenna placement information elements in freifunk map data
• Search in Wireless Mesh Networks - Yacy
• Search in Wireless Mesh Networks - Nutch/Lucene
• Peer-to-peer file sharing applications in Wireless Mesh Networks
• Developing a Freifunk Theme for CMS
• VoIP phoning in Freifunk Mesh Networks
• Porting Freifunk to EeePC
• Freifunk Webinterface for OpenWrt Kamikaze
• more ideas are welcome...