blog/archive/2013/10/10.rss

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   4                 <title>Petter Reinholdtsen - Entries from October 2013</title>
   5                 <description>Entries from October 2013</description>
   6                 <link>http://people.skolelinux.org/pere/blog/</link>
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   9         <item>
  10                 <title>Oslo community mesh network - with NUUG and Hackeriet at Hausmania</title>
  11                 <link>http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</link>
  12                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</guid>
  13                 <pubDate>Fri, 11 Oct 2013 14:10:00 +0200</pubDate>
  14                 <description>&lt;p&gt;Wireless mesh networks are self organising and self healing
  15 networks that can be used to connect computers across small and large
  16 areas, depending on the radio technology used.  Normal wifi equipment
  17 can be used to create home made radio networks, and there are several
  18 successful examples like
  19 &lt;a href=&quot;http://www.freifunk.net/&quot;&gt;Freifunk&lt;/a&gt; and
  20 &lt;a href=&quot;http://www.awmn.net/&quot;&gt;Athens Wireless Metropolitan Network&lt;/a&gt;
  21 (see
  22 &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_wireless_community_networks_by_region#Greece&quot;&gt;wikipedia
  23 for a large list&lt;/a&gt;) around the globe.  To give you an idea how it
  24 work, check out the nice overview of the Kiel Freifunk community which
  25 can be seen from their
  26 &lt;a href=&quot;http://freifunk.in-kiel.de/ffmap/nodes.html&quot;&gt;dynamically
  27 updated node graph and map&lt;/a&gt;, where one can see how the mesh nodes
  28 automatically handle routing and recover from nodes disappearing.
  29 There is also a small community mesh network group in Oslo, Norway,
  30 and that is the main topic of this blog post.&lt;/p&gt;
  31
  32 &lt;p&gt;I&#39;ve wanted to check out mesh networks for a while now, and hoped
  33 to do it as part of my involvement with the &lt;a
  34 href=&quot;http://www.nuug.no/&quot;&gt;NUUG member organisation&lt;/a&gt; community, and
  35 my recent involvement in
  36 &lt;a href=&quot;https://wiki.debian.org/FreedomBox&quot;&gt;the Freedombox project&lt;/a&gt;
  37 finally lead me to give mesh networks some priority, as I suspect a
  38 Freedombox should use mesh networks to connect neighbours and family
  39 when possible, given that most communication between people are
  40 between those nearby (as shown for example by research on Facebook
  41 communication patterns).  It also allow people to communicate without
  42 any central hub to tap into for those that want to listen in on the
  43 private communication of citizens, which have become more and more
  44 important over the years.&lt;/p&gt;
  45
  46 &lt;p&gt;So far I have only been able to find one group of people in Oslo
  47 working on community mesh networks, over at the hack space
  48 &lt;a href=&quot;http://hackeriet.no/&quot;&gt;Hackeriet&lt;/a&gt; at Husmania.  They seem to
  49 have started with some Freifunk based effort using OLSR, called
  50 &lt;a href=&quot;http://oslo.freifunk.net/index.php?title=Main_Page&quot;&gt;the Oslo
  51 Freifunk project&lt;/a&gt;, but that effort is now dead and the people
  52 behind it have moved on to a batman-adv based system called
  53 &lt;a href=&quot;http://meshfx.org/trac&quot;&gt;meshfx&lt;/a&gt;.  Unfortunately the wiki
  54 site for the Oslo Freifunk project is no longer possible to update to
  55 reflect this fact, so the old project page can&#39;t be updated to point to
  56 the new project.  A while back, the people at Hackeriet invited people
  57 from the Freifunk community to Oslo to talk about mesh networks.  I
  58 came across this video where Hans Jørgen Lysglimt interview the
  59 speakers about this talk (from
  60 &lt;a href=&quot;https://www.youtube.com/watch?v=N2Kd7CLkhSY&quot;&gt;youtube&lt;/a&gt;:&lt;/p&gt;
  61
  62
  63 &lt;p&gt;&lt;iframe width=&quot;420&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/N2Kd7CLkhSY&quot; frameborder=&quot;0&quot; allowfullscreen&gt;&lt;/iframe&gt;&lt;/p&gt;
  64
  65 &lt;p&gt;I mentioned OLSR and batman-adv, which are mesh routing protocols.
  66 There are heaps of different protocols, and I am still struggling to
  67 figure out which one would be &quot;best&quot; for some definitions of best, but
  68 given that the community mesh group in Oslo is so small, I believe it
  69 is best to hook up with the existing one instead of trying to create a
  70 completely different setup, and thus this have decided to focus on
  71 batman-adv for now.  It sure help me to  know that the very cool
  72 &lt;a href=&quot;http://www.servalproject.org/&quot;&gt;Serval project in Australia&lt;/a&gt;
  73 is using batman-adv as their meshing technology when it create a self
  74 organizing and self healing telephony system for disaster areas and
  75 less industrialized communities.  Check out this cool video presenting
  76 that project (from
  77 &lt;a href=&quot;https://www.youtube.com/watch?v=30qNfzJCQOA&quot;&gt;youtube&lt;/a&gt;:&lt;/p&gt;
  78
  79 &lt;p&gt;&lt;iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/30qNfzJCQOA&quot; frameborder=&quot;0&quot; allowfullscreen&gt;&lt;/iframe&gt;&lt;/p&gt;
  80
  81 &lt;p&gt;According to the wikipedia page on
  82 &lt;a href=&quot;http://en.wikipedia.org/wiki/Wireless_mesh_network&quot;&gt;Wireless
  83 mesh network&lt;/a&gt; there are around 70 competing schemes for routing
  84 packets across mesh networks, and OLSR, B.A.T.M.A.N. and
  85 B.A.T.M.A.N. advanced are protocols used by several free software
  86 based community mesh networks.&lt;/p&gt;
  87
  88 &lt;/p&gt;The batman-adv protocol is a bit special, as it provide layer 2
  89 (as in ethernet ) routing, allowing ipv4 and ipv6 to work on the same
  90 network.  One way to think about it is that it provide a mesh based
  91 vlan you can bridge to or handle like any other vlan connected to your
  92 computer.  The required drivers are already in the Linux kernel at
  93 least since Debian Wheezy, and it is fairly easy to set up.  A
  94 &lt;a href=&quot;http://www.open-mesh.org/projects/batman-adv/wiki/Quick-start-guide&quot;&gt;good
  95 introduction&lt;/a&gt; is available from the Open Mesh project.  These are
  96 the key settings needed to join the Oslo meshfx network:&lt;/p&gt;
  97
  98 &lt;table&gt;
  99 &lt;tr&gt;&lt;th&gt;Setting&lt;/th&gt;&lt;th&gt;Value&lt;/th&gt;&lt;/tr&gt;
 100 &lt;tr&gt;&lt;td&gt;Protocol / kernel module&lt;/td&gt;&lt;td&gt;batman-adv&lt;/td&gt;&lt;/tr&gt;
 101 &lt;tr&gt;&lt;td&gt;ESSID&lt;/td&gt;&lt;td&gt;meshfx@hackeriet&lt;/td&gt;&lt;/tr&gt;
 102 &lt;td&gt;Channel / Frequency&lt;/td&gt;&lt;td&gt;11 / 2462&lt;/td&gt;&lt;/tr&gt;
 103 &lt;td&gt;Cell ID&lt;/td&gt;&lt;td&gt;02:BA:00:00:00:01&lt;/td&gt;
 104 &lt;/table&gt;
 105
 106 &lt;p&gt;The reason for setting ad-hoc wifi Cell ID is to work around bugs
 107 in firmware used in wifi card and wifi drivers.  (See a nice post from
 108 VillageTelco about
 109 &quot;&lt;a href=&quot;http://tiebing.blogspot.no/2009/12/ad-hoc-cell-splitting-re-post-original.html&quot;&gt;Information
 110 about cell-id splitting, stuck beacons, and failed IBSS merges!&lt;/a&gt;
 111 for details.)  When these settings are activated and you have some
 112 other mesh node nearby, your computer will be connected to the mesh
 113 network and can communicate with any mesh node that is connected to
 114 any of the nodes in your network of nodes. :)&lt;/p&gt;
 115
 116 &lt;p&gt;My initial plan was to reuse my old Linksys WRT54GL as a mesh node,
 117 but that seem to be very hard, as I have not been able to locate a
 118 firmware supporting batman-adv.  If anyone know how to use that old
 119 wifi access point with batman-adv these days, please let me know.&lt;/p&gt;
 120
 121 &lt;p&gt;If you find this project interesting and want to join, please join
 122 us on IRC, either channel
 123 &lt;a href=&quot;irc://irc.freenode.net/#oslohackerspace&quot;&gt;#oslohackerspace&lt;/a&gt;
 124 or &lt;a href=&quot;irc://irc.freenode.net/#nuug&quot;&gt;#nuug&lt;/a&gt; on
 125 irc.freenode.net.&lt;/p&gt;
 126
 127 &lt;p&gt;While investigating mesh networks in Oslo, I came across an old
 128 research paper from the university of Stavanger and Telenor Research
 129 and Innovation called
 130 &lt;a href=&quot;http://folk.uio.no/paalee/publications/netrel-egeland-iswcs-2008.pdf&quot;&gt;The
 131 reliability of wireless backhaul mesh networks&lt;/a&gt; and elsewhere
 132 learned that Telenor have been experimenting with mesh networks at
 133 Grünerløkka in Oslo.  So mesh networks are also interesting for
 134 commercial companies, even though Telenor discovered that it was hard
 135 to figure out a good business plan for mesh networking and as far as I
 136 know have closed down the experiment.  Perhaps Telenor or others would
 137 be interested in a cooperation?&lt;/p&gt;
 138 </description>
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 142                 <title>Skolelinux / Debian Edu 7.1 install and overview video from Marcelo Salvador</title>
 143                 <link>http://people.skolelinux.org/pere/blog/Skolelinux___Debian_Edu_7_1_install_and_overview_video_from_Marcelo_Salvador.html</link>
 144                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Skolelinux___Debian_Edu_7_1_install_and_overview_video_from_Marcelo_Salvador.html</guid>
 145                 <pubDate>Tue, 8 Oct 2013 17:10:00 +0200</pubDate>
 146                 <description>&lt;p&gt;The other day I was pleased and surprised to discover that Marcelo
 147 Salvador had published a
 148 &lt;a href=&quot;https://www.youtube.com/watch?v=w-GgpdqgLFc&quot;&gt;video on
 149 Youtube&lt;/a&gt; showing how to install the standalone Debian Edu /
 150 Skolelinux profile.  This is the profile intended for use at home or
 151 on laptops that should not be integrated into the provided network
 152 services (no central home directory, no Kerberos / LDAP directory etc,
 153 in other word a single user machine).  The result is 11 minutes long,
 154 and show some user applications (seem to be rather randomly picked).
 155 Missed a few of my favorites like celestia, planets and chromium
 156 showing the &lt;a href=&quot;http://www.zygotebody.com/&quot;&gt;Zygote Body 3D model
 157 of the human body&lt;/a&gt;, but I guess he did not know about those or find
 158 other programs more interesting. :) And the video do not show the
 159 advantages I believe is one of the most valuable featuers in Debian
 160 Edu, its central school server making it possible to run hundreds of
 161 computers without hard drives by installing one central
 162 &lt;a href=&quot;http://www.ltsp.org/&quot;&gt;LTSP server&lt;/a&gt;.&lt;/p&gt;
 163
 164 &lt;p&gt;Anyway, check out the video, embedded below and linked to above:&lt;/p&gt;
 165
 166 &lt;iframe width=&quot;420&quot; height=&quot;315&quot; src=&quot;http://www.youtube.com/embed/w-GgpdqgLFc&quot; frameborder=&quot;0&quot; allowfullscreen&gt;&lt;/iframe&gt;
 167
 168 &lt;p&gt;Are there other nice videos demonstrating Skolelinux?  Please let
 169 me know. :)&lt;/p&gt;
 170 </description>
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