blog/tags/mesh network/mesh network.rss

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   4                 <title>Petter Reinholdtsen - Entries tagged mesh network</title>
   5                 <description>Entries tagged mesh network</description>
   6                 <link>http://people.skolelinux.org/pere/blog/</link>
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   9         <item>
  10                 <title>A Raspberry Pi based batman-adv Mesh network node</title>
  11                 <link>http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html</link>
  12                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html</guid>
  13                 <pubDate>Mon, 21 Oct 2013 11:40:00 +0200</pubDate>
  14                 <description>&lt;p&gt;The last few days I have been experimenting with
  15 &lt;a href=&quot;http://www.open-mesh.org/projects/batman-adv/wiki&quot;&gt;the
  16 batman-adv mesh technology&lt;/a&gt;.  I want to gain some experience to see
  17 if it will fit &lt;a href=&quot;https://wiki.debian.org/FreedomBox&quot;&gt;the
  18 Freedombox project&lt;/a&gt;, and together with my neighbors try to build a
  19 mesh network around the park where I live.  Batman-adv is a layer 2
  20 mesh system (&quot;ethernet&quot; in other words), where the mesh network appear
  21 as if all the mesh clients are connected to the same switch.&lt;/p&gt;
  22
  23 &lt;p&gt;My hardware of choice was the Linksys WRT54GL routers I had lying
  24 around, but I&#39;ve been unable to get them working with batman-adv.  So
  25 instead, I started playing with a
  26 &lt;a href=&quot;http://www.raspberrypi.org/&quot;&gt;Raspberry Pi&lt;/a&gt;, and tried to
  27 get it working as a mesh node.  My idea is to use it to create a mesh
  28 node which function as a switch port, where everything connected to
  29 the Raspberry Pi ethernet plug is connected (bridged) to the mesh
  30 network.  This allow me to hook a wifi base station like the Linksys
  31 WRT54GL to the mesh by plugging it into a Raspberry Pi, and allow
  32 non-mesh clients to hook up to the mesh.  This in turn is useful for
  33 Android phones using &lt;a href=&quot;http://servalproject.org/&quot;&gt;the Serval
  34 Project&lt;/a&gt; voip client, allowing every one around the playground to
  35 phone and message each other for free.  The reason is that Android
  36 phones do not see ad-hoc wifi networks (they are filtered away from
  37 the GUI view), and can not join the mesh without being rooted.  But if
  38 they are connected using a normal wifi base station, they can talk to
  39 every client on the local network.&lt;/p&gt;
  40
  41 &lt;p&gt;To get this working, I&#39;ve created a debian package
  42 &lt;a href=&quot;https://github.com/petterreinholdtsen/meshfx-node&quot;&gt;meshfx-node&lt;/a&gt;
  43 and a script
  44 &lt;a href=&quot;https://github.com/petterreinholdtsen/meshfx-node/blob/master/build-rpi-mesh-node&quot;&gt;build-rpi-mesh-node&lt;/a&gt;
  45 to create the Raspberry Pi boot image.  I&#39;m using Debian Jessie (and
  46 not Raspbian), to get more control over the packages available.
  47 Unfortunately a huge binary blob need to be inserted into the boot
  48 image to get it booting, but I&#39;ll ignore that for now.  Also, as
  49 Debian lack support for the CPU features available in the Raspberry
  50 Pi, the system do not use the hardware floating point unit.  I hope
  51 the routing performance isn&#39;t affected by the lack of hardware FPU
  52 support.&lt;/p&gt;
  53
  54 &lt;p&gt;To create an image, run the following with a sudo enabled user
  55 after inserting the target SD card into the build machine:&lt;/p&gt;
  56
  57 &lt;p&gt;&lt;pre&gt;
  58 % wget -O build-rpi-mesh-node \
  59     https://raw.github.com/petterreinholdtsen/meshfx-node/master/build-rpi-mesh-node
  60 % sudo bash -x ./build-rpi-mesh-node &gt; build.log 2&gt;&amp;1
  61 % dd if=/root/rpi/rpi_basic_jessie_$(date +%Y%m%d).img of=/dev/mmcblk0 bs=1M
  62 %
  63 &lt;/pre&gt;&lt;/p&gt;
  64
  65 &lt;p&gt;Booting with the resulting SD card on a Raspberry PI with a USB
  66 wifi card inserted should give you a mesh node.  At least it does for
  67 me with a the wifi card I am using. The default mesh settings are the
  68 ones used by the Oslo mesh project at Hackeriet, as I mentioned in
  69 &lt;a href=&quot;http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html&quot;&gt;an
  70 earlier blog post about this mesh testing&lt;/a&gt;.&lt;/p&gt;
  71
  72 &lt;p&gt;The mesh node was not horribly expensive either.  I bought
  73 everything over the counter in shops nearby.  If I had ordered online
  74 from the lowest bidder, the price should be significantly lower:&lt;/p&gt;
  75
  76 &lt;p&gt;&lt;table&gt;
  77
  78 &lt;tr&gt;&lt;th&gt;Supplier&lt;/th&gt;&lt;th&gt;Model&lt;/th&gt;&lt;th&gt;NOK&lt;/th&gt;&lt;/tr&gt;
  79 &lt;tr&gt;&lt;td&gt;Teknikkmagasinet&lt;/td&gt;&lt;td&gt;Raspberry Pi model B&lt;/td&gt;&lt;td&gt;349.90&lt;/td&gt;&lt;/tr&gt;
  80 &lt;tr&gt;&lt;td&gt;Teknikkmagasinet&lt;/td&gt;&lt;td&gt;Raspberry Pi type B case&lt;/td&gt;&lt;td&gt;99.90&lt;/td&gt;&lt;/tr&gt;
  81 &lt;tr&gt;&lt;td&gt;Lefdal&lt;/td&gt;&lt;td&gt;Jensen Air:Link 25150&lt;/td&gt;&lt;td&gt;295.-&lt;/td&gt;&lt;/tr&gt;
  82 &lt;tr&gt;&lt;td&gt;Clas Ohlson&lt;/td&gt;&lt;td&gt;Kingston 16 GB SD card&lt;/td&gt;&lt;td&gt;199.-&lt;/td&gt;&lt;/tr&gt;
  83 &lt;tr&gt;&lt;td&gt;Total cost&lt;/td&gt;&lt;td&gt;&lt;/td&gt;&lt;td&gt;943.80&lt;/td&gt;&lt;/tr&gt;
  84
  85 &lt;/table&gt;&lt;/p&gt;
  86
  87 &lt;p&gt;Now my mesh network at home consist of one laptop in the basement
  88 connected to my production network, one Raspberry Pi node on the 1th
  89 floor that can be seen by my neighbor across the park, and one
  90 play-node I use to develop the image building script.  And some times
  91 I hook up my work horse laptop to the mesh to test it.  I look forward
  92 to figuring out what kind of latency the batman-adv setup will give,
  93 and how much packet loss we will experience around the park. :)&lt;/p&gt;
  94 </description>
  95         </item>
  96
  97         <item>
  98                 <title>Oslo community mesh network - with NUUG and Hackeriet at Hausmania</title>
  99                 <link>http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</link>
 100                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</guid>
 101                 <pubDate>Fri, 11 Oct 2013 14:10:00 +0200</pubDate>
 102                 <description>&lt;p&gt;Wireless mesh networks are self organising and self healing
 103 networks that can be used to connect computers across small and large
 104 areas, depending on the radio technology used.  Normal wifi equipment
 105 can be used to create home made radio networks, and there are several
 106 successful examples like
 107 &lt;a href=&quot;http://www.freifunk.net/&quot;&gt;Freifunk&lt;/a&gt; and
 108 &lt;a href=&quot;http://www.awmn.net/&quot;&gt;Athens Wireless Metropolitan Network&lt;/a&gt;
 109 (see
 110 &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_wireless_community_networks_by_region#Greece&quot;&gt;wikipedia
 111 for a large list&lt;/a&gt;) around the globe.  To give you an idea how it
 112 work, check out the nice overview of the Kiel Freifunk community which
 113 can be seen from their
 114 &lt;a href=&quot;http://freifunk.in-kiel.de/ffmap/nodes.html&quot;&gt;dynamically
 115 updated node graph and map&lt;/a&gt;, where one can see how the mesh nodes
 116 automatically handle routing and recover from nodes disappearing.
 117 There is also a small community mesh network group in Oslo, Norway,
 118 and that is the main topic of this blog post.&lt;/p&gt;
 119
 120 &lt;p&gt;I&#39;ve wanted to check out mesh networks for a while now, and hoped
 121 to do it as part of my involvement with the &lt;a
 122 href=&quot;http://www.nuug.no/&quot;&gt;NUUG member organisation&lt;/a&gt; community, and
 123 my recent involvement in
 124 &lt;a href=&quot;https://wiki.debian.org/FreedomBox&quot;&gt;the Freedombox project&lt;/a&gt;
 125 finally lead me to give mesh networks some priority, as I suspect a
 126 Freedombox should use mesh networks to connect neighbours and family
 127 when possible, given that most communication between people are
 128 between those nearby (as shown for example by research on Facebook
 129 communication patterns).  It also allow people to communicate without
 130 any central hub to tap into for those that want to listen in on the
 131 private communication of citizens, which have become more and more
 132 important over the years.&lt;/p&gt;
 133
 134 &lt;p&gt;So far I have only been able to find one group of people in Oslo
 135 working on community mesh networks, over at the hack space
 136 &lt;a href=&quot;http://hackeriet.no/&quot;&gt;Hackeriet&lt;/a&gt; at Husmania.  They seem to
 137 have started with some Freifunk based effort using OLSR, called
 138 &lt;a href=&quot;http://oslo.freifunk.net/index.php?title=Main_Page&quot;&gt;the Oslo
 139 Freifunk project&lt;/a&gt;, but that effort is now dead and the people
 140 behind it have moved on to a batman-adv based system called
 141 &lt;a href=&quot;http://meshfx.org/trac&quot;&gt;meshfx&lt;/a&gt;.  Unfortunately the wiki
 142 site for the Oslo Freifunk project is no longer possible to update to
 143 reflect this fact, so the old project page can&#39;t be updated to point to
 144 the new project.  A while back, the people at Hackeriet invited people
 145 from the Freifunk community to Oslo to talk about mesh networks.  I
 146 came across this video where Hans Jørgen Lysglimt interview the
 147 speakers about this talk (from
 148 &lt;a href=&quot;https://www.youtube.com/watch?v=N2Kd7CLkhSY&quot;&gt;youtube&lt;/a&gt;):&lt;/p&gt;
 149
 150 &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;
 151
 152 &lt;p&gt;I mentioned OLSR and batman-adv, which are mesh routing protocols.
 153 There are heaps of different protocols, and I am still struggling to
 154 figure out which one would be &quot;best&quot; for some definitions of best, but
 155 given that the community mesh group in Oslo is so small, I believe it
 156 is best to hook up with the existing one instead of trying to create a
 157 completely different setup, and thus I have decided to focus on
 158 batman-adv for now.  It sure help me to  know that the very cool
 159 &lt;a href=&quot;http://www.servalproject.org/&quot;&gt;Serval project in Australia&lt;/a&gt;
 160 is using batman-adv as their meshing technology when it create a self
 161 organizing and self healing telephony system for disaster areas and
 162 less industrialized communities.  Check out this cool video presenting
 163 that project (from
 164 &lt;a href=&quot;https://www.youtube.com/watch?v=30qNfzJCQOA&quot;&gt;youtube&lt;/a&gt;):&lt;/p&gt;
 165
 166 &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;
 167
 168 &lt;p&gt;According to the wikipedia page on
 169 &lt;a href=&quot;http://en.wikipedia.org/wiki/Wireless_mesh_network&quot;&gt;Wireless
 170 mesh network&lt;/a&gt; there are around 70 competing schemes for routing
 171 packets across mesh networks, and OLSR, B.A.T.M.A.N. and
 172 B.A.T.M.A.N. advanced are protocols used by several free software
 173 based community mesh networks.&lt;/p&gt;
 174
 175 &lt;p&gt;The batman-adv protocol is a bit special, as it provide layer 2
 176 (as in ethernet ) routing, allowing ipv4 and ipv6 to work on the same
 177 network.  One way to think about it is that it provide a mesh based
 178 vlan you can bridge to or handle like any other vlan connected to your
 179 computer.  The required drivers are already in the Linux kernel at
 180 least since Debian Wheezy, and it is fairly easy to set up.  A
 181 &lt;a href=&quot;http://www.open-mesh.org/projects/batman-adv/wiki/Quick-start-guide&quot;&gt;good
 182 introduction&lt;/a&gt; is available from the Open Mesh project.  These are
 183 the key settings needed to join the Oslo meshfx network:&lt;/p&gt;
 184
 185 &lt;p&gt;&lt;table&gt;
 186 &lt;tr&gt;&lt;th&gt;Setting&lt;/th&gt;&lt;th&gt;Value&lt;/th&gt;&lt;/tr&gt;
 187 &lt;tr&gt;&lt;td&gt;Protocol / kernel module&lt;/td&gt;&lt;td&gt;batman-adv&lt;/td&gt;&lt;/tr&gt;
 188 &lt;tr&gt;&lt;td&gt;ESSID&lt;/td&gt;&lt;td&gt;meshfx@hackeriet&lt;/td&gt;&lt;/tr&gt;
 189 &lt;td&gt;Channel / Frequency&lt;/td&gt;&lt;td&gt;11 / 2462&lt;/td&gt;&lt;/tr&gt;
 190 &lt;td&gt;Cell ID&lt;/td&gt;&lt;td&gt;02:BA:00:00:00:01&lt;/td&gt;
 191 &lt;/table&gt;&lt;/p&gt;
 192
 193 &lt;p&gt;The reason for setting ad-hoc wifi Cell ID is to work around bugs
 194 in firmware used in wifi card and wifi drivers.  (See a nice post from
 195 VillageTelco about
 196 &quot;&lt;a href=&quot;http://tiebing.blogspot.no/2009/12/ad-hoc-cell-splitting-re-post-original.html&quot;&gt;Information
 197 about cell-id splitting, stuck beacons, and failed IBSS merges!&lt;/a&gt;
 198 for details.)  When these settings are activated and you have some
 199 other mesh node nearby, your computer will be connected to the mesh
 200 network and can communicate with any mesh node that is connected to
 201 any of the nodes in your network of nodes. :)&lt;/p&gt;
 202
 203 &lt;p&gt;My initial plan was to reuse my old Linksys WRT54GL as a mesh node,
 204 but that seem to be very hard, as I have not been able to locate a
 205 firmware supporting batman-adv.  If anyone know how to use that old
 206 wifi access point with batman-adv these days, please let me know.&lt;/p&gt;
 207
 208 &lt;p&gt;If you find this project interesting and want to join, please join
 209 us on IRC, either channel
 210 &lt;a href=&quot;irc://irc.freenode.net/#oslohackerspace&quot;&gt;#oslohackerspace&lt;/a&gt;
 211 or &lt;a href=&quot;irc://irc.freenode.net/#nuug&quot;&gt;#nuug&lt;/a&gt; on
 212 irc.freenode.net.&lt;/p&gt;
 213
 214 &lt;p&gt;While investigating mesh networks in Oslo, I came across an old
 215 research paper from the university of Stavanger and Telenor Research
 216 and Innovation called
 217 &lt;a href=&quot;http://folk.uio.no/paalee/publications/netrel-egeland-iswcs-2008.pdf&quot;&gt;The
 218 reliability of wireless backhaul mesh networks&lt;/a&gt; and elsewhere
 219 learned that Telenor have been experimenting with mesh networks at
 220 Grünerløkka in Oslo.  So mesh networks are also interesting for
 221 commercial companies, even though Telenor discovered that it was hard
 222 to figure out a good business plan for mesh networking and as far as I
 223 know have closed down the experiment.  Perhaps Telenor or others would
 224 be interested in a cooperation?&lt;/p&gt;
 225
 226 &lt;p&gt;&lt;strong&gt;Update 2013-10-12&lt;/strong&gt;: I was just
 227 &lt;a href=&quot;http://lists.alioth.debian.org/pipermail/freedombox-discuss/2013-October/005900.html&quot;&gt;told
 228 by the Serval project developers&lt;/a&gt; that they no longer use
 229 batman-adv (but are compatible with it), but their own crypto based
 230 mesh system.&lt;/p&gt;
 231 </description>
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