1 <?xml version=
"1.0" encoding=
"utf-8"?>
2 <rss version='
2.0' xmlns:lj='http://www.livejournal.org/rss/lj/
1.0/'
>
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>
10 <title>Running TP-Link MR3040 as a batman-adv mesh node using openwrt
</title>
11 <link>http://people.skolelinux.org/pere/blog/Running_TP_Link_MR3040_as_a_batman_adv_mesh_node_using_openwrt.html
</link>
12 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Running_TP_Link_MR3040_as_a_batman_adv_mesh_node_using_openwrt.html
</guid>
13 <pubDate>Sun,
10 Nov
2013 23:
00:
00 +
0100</pubDate>
14 <description><p
>Continuing my research into mesh networking, I was recommended to
15 use TP-Link
3040 and
3600 access points as mesh nodes, and the pair I
16 bought arrived on Friday. Here are my notes on how to set up the
17 MR3040 as a mesh node using
18 <a href=
"http://www.openwrt.org/
">OpenWrt
</a
>.
</p
>
20 <p
>I started by following the instructions on the OpenWRT wiki for
21 <a href=
"http://wiki.openwrt.org/toh/tp-link/tl-mr3040
">TL-MR3040
</a
>,
23 <a href=
"http://downloads.openwrt.org/snapshots/trunk/ar71xx/openwrt-ar71xx-generic-tl-mr3040-v2-squashfs-factory.bin
">the
24 recommended firmware image
</a
>
25 (openwrt-ar71xx-generic-tl-mr3040-v2-squashfs-factory.bin) and
26 uploaded it into the original web interface. The flashing went fine,
27 and the machine was available via telnet on the ethernet port. After
28 logging in and setting the root password, ssh was available and I
29 could start to set it up as a batman-adv mesh node.
</p
>
31 <p
>I started off by reading the instructions from
32 <a href=
"http://wirelessafrica.meraka.org.za/wiki/index.php?title=Antoine
's_Research
">Wireless
33 Africa
</a
>, which had quite a lot of useful information, but
34 eventually I followed the recipe from the Open Mesh wiki for
35 <a href=
"http://www.open-mesh.org/projects/batman-adv/wiki/Batman-adv-openwrt-config
">using
36 batman-adv on OpenWrt
</a
>. A small snag was the fact that the
37 <tt
>opkg install kmod-batman-adv
</tt
> command did not work as it
38 should. The batman-adv kernel module would fail to load because its
39 dependency crc16 was not already loaded. I
40 <a href=
"https://dev.openwrt.org/ticket/
14452">reported the bug
</a
> to
41 the openwrt project and hope it will be fixed soon. But the problem
42 only seem to affect initial testing of batman-adv, as configuration
43 seem to work when booting from scratch.
</p
>
45 <p
>The setup is done using files in /etc/config/. I did not bridge
46 the Ethernet and mesh interfaces this time, to be able to hook up the
47 box on my local network and log into it for configuration updates.
48 The following files were changed and look like this after modifying
51 <p
><tt
>/etc/config/network
</tt
></p
>
55 config interface
'loopback
'
56 option ifname
'lo
'
57 option proto
'static
'
58 option ipaddr
'127.0.0.1'
59 option netmask
'255.0.0.0'
61 config globals
'globals
'
62 option ula_prefix
'fdbf:
4c12:
3fed::/
48'
64 config interface
'lan
'
65 option ifname
'eth0
'
66 option type
'bridge
'
67 option proto
'dhcp
'
68 option ipaddr
'192.168.1.1'
69 option netmask
'255.255.255.0'
70 option hostname
'tl-mr3040
'
71 option ip6assign
'60'
73 config interface
'mesh
'
74 option ifname
'adhoc0
'
75 option mtu
'1528'
76 option proto
'batadv
'
77 option mesh
'bat0
'
80 <p
><tt
>/etc/config/wireless
</tt
></p
>
83 config wifi-device
'radio0
'
84 option type
'mac80211
'
85 option channel
'11'
86 option hwmode
'11ng
'
87 option path
'platform/ar933x_wmac
'
88 option htmode
'HT20
'
89 list ht_capab
'SHORT-GI-
20'
90 list ht_capab
'SHORT-GI-
40'
91 list ht_capab
'RX-STBC1
'
92 list ht_capab
'DSSS_CCK-
40'
93 option disabled
'0'
95 config wifi-iface
'wmesh
'
96 option device
'radio0
'
97 option ifname
'adhoc0
'
98 option network
'mesh
'
99 option encryption
'none
'
100 option mode
'adhoc
'
101 option bssid
'02:BA:
00:
00:
00:
01'
102 option ssid
'meshfx@hackeriet
'
104 <p
><tt
>/etc/config/batman-adv
</tt
></p
>
107 config
'mesh
' 'bat0
'
108 option interfaces
'adhoc0
'
109 option
'aggregated_ogms
'
110 option
'ap_isolation
'
111 option
'bonding
'
112 option
'fragmentation
'
113 option
'gw_bandwidth
'
114 option
'gw_mode
'
115 option
'gw_sel_class
'
116 option
'log_level
'
117 option
'orig_interval
'
118 option
'vis_mode
'
119 option
'bridge_loop_avoidance
'
120 option
'distributed_arp_table
'
121 option
'network_coding
'
122 option
'hop_penalty
'
124 # yet another batX instance
125 # config
'mesh
' 'bat5
'
126 # option
'interfaces
' 'second_mesh
'
129 <p
>The mesh node is now operational. I have yet to test its range,
130 but I hope it is good. I have not yet tested the TP-Link
3600 box
131 still wrapped up in plastic.
</p
>
136 <title>Teaching vmdebootstrap to create Raspberry Pi SD card images
</title>
137 <link>http://people.skolelinux.org/pere/blog/Teaching_vmdebootstrap_to_create_Raspberry_Pi_SD_card_images.html
</link>
138 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Teaching_vmdebootstrap_to_create_Raspberry_Pi_SD_card_images.html
</guid>
139 <pubDate>Sun,
27 Oct
2013 17:
00:
00 +
0100</pubDate>
140 <description><p
>The
141 <a href=
"http://packages.qa.debian.org/v/vmdebootstrap.html
">vmdebootstrap
</a
>
142 program is a a very nice system to create virtual machine images. It
143 create a image file, add a partition table, mount it and run
144 debootstrap in the mounted directory to create a Debian system on a
145 stick. Yesterday, I decided to try to teach it how to make images for
146 <a href=
"https://wiki.debian.org/RaspberryPi
">Raspberry Pi
</a
>, as part
147 of a plan to simplify the build system for
148 <a href=
"https://wiki.debian.org/FreedomBox
">the FreedomBox
149 project
</a
>. The FreedomBox project already uses vmdebootstrap for
150 the virtualbox images, but its current build system made multistrap
151 based system for Dreamplug images, and it is lacking support for
152 Raspberry Pi.
</p
>
154 <p
>Armed with the knowledge on how to build
"foreign
" (aka non-native
155 architecture) chroots for Raspberry Pi, I dived into the vmdebootstrap
156 code and adjusted it to be able to build armel images on my amd64
157 Debian laptop. I ended up giving vmdebootstrap five new options,
158 allowing me to replicate the image creation process I use to make
159 <a href=
"http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html
">Debian
160 Jessie based mesh node images for the Raspberry Pi
</a
>. First, the
161 <tt
>--foreign /path/to/binfm_handler
</tt
> option tell vmdebootstrap to
162 call debootstrap with --foreign and to copy the handler into the
163 generated chroot before running the second stage. This allow
164 vmdebootstrap to create armel images on an amd64 host. Next I added
165 two new options
<tt
>--bootsize size
</tt
> and
<tt
>--boottype
166 fstype
</tt
> to teach it to create a separate /boot/ partition with the
167 given file system type, allowing me to create an image with a vfat
168 partition for the /boot/ stuff. I also added a
<tt
>--variant
169 variant
</tt
> option to allow me to create smaller images without the
170 Debian base system packages installed. Finally, I added an option
171 <tt
>--no-extlinux
</tt
> to tell vmdebootstrap to not install extlinux
172 as a boot loader. It is not needed on the Raspberry Pi and probably
173 most other non-x86 architectures. The changes were accepted by the
174 upstream author of vmdebootstrap yesterday and today, and is now
176 <a href=
"http://git.liw.fi/cgi-bin/cgit/cgit.cgi/vmdebootstrap/
">the
177 upstream project page
</a
>.
</p
>
179 <p
>To use it to build a Raspberry Pi image using Debian Jessie, first
180 create a small script (the customize script) to add the non-free
181 binary blob needed to boot the Raspberry Pi and the APT source
186 set -e # Exit on first error
187 rootdir=
"$
1"
188 cd
"$rootdir
"
189 cat
&lt;
&lt;EOF
> etc/apt/sources.list
190 deb http://http.debian.net/debian/ jessie main contrib non-free
192 # Install non-free binary blob needed to boot Raspberry Pi. This
193 # install a kernel somewhere too.
194 wget https://raw.github.com/Hexxeh/rpi-update/master/rpi-update \
195 -O $rootdir/usr/bin/rpi-update
196 chmod a+x $rootdir/usr/bin/rpi-update
197 mkdir -p $rootdir/lib/modules
198 touch $rootdir/boot/start.elf
199 chroot $rootdir rpi-update
200 </pre
></p
>
202 <p
>Next, fetch the latest vmdebootstrap script and call it like this
203 to build the image:
</p
>
206 sudo ./vmdebootstrap \
209 --distribution jessie \
210 --mirror http://http.debian.net/debian \
219 --root-password raspberry \
220 --hostname raspberrypi \
221 --foreign /usr/bin/qemu-arm-static \
222 --customize `pwd`/customize \
226 --package ca-certificates \
229 </pre
></p
>
231 <p
>The list of packages being installed are the ones needed by
232 rpi-update to make the image bootable on the Raspberry Pi, with the
233 exception of netbase, which is needed by debootstrap to find
234 /etc/hosts with the minbase variant. I really wish there was a way to
235 set up an Raspberry Pi using only packages in the Debian archive, but
236 that is not possible as far as I know, because it boots from the GPU
237 using a non-free binary blob.
</p
>
239 <p
>The build host need debootstrap, kpartx and qemu-user-static and
240 probably a few others installed. I have not checked the complete
241 build dependency list.
</p
>
243 <p
>The resulting image will not use the hardware floating point unit
244 on the Raspberry PI, because the armel architecture in Debian is not
245 optimized for that use. So the images created will be a bit slower
246 than
<a href=
"http://www.raspbian.org/
">Raspbian
</a
> based images.
</p
>
251 <title>A Raspberry Pi based batman-adv Mesh network node
</title>
252 <link>http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html
</link>
253 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html
</guid>
254 <pubDate>Mon,
21 Oct
2013 11:
40:
00 +
0200</pubDate>
255 <description><p
>The last few days I have been experimenting with
256 <a href=
"http://www.open-mesh.org/projects/batman-adv/wiki
">the
257 batman-adv mesh technology
</a
>. I want to gain some experience to see
258 if it will fit
<a href=
"https://wiki.debian.org/FreedomBox
">the
259 Freedombox project
</a
>, and together with my neighbors try to build a
260 mesh network around the park where I live. Batman-adv is a layer
2
261 mesh system (
"ethernet
" in other words), where the mesh network appear
262 as if all the mesh clients are connected to the same switch.
</p
>
264 <p
>My hardware of choice was the Linksys WRT54GL routers I had lying
265 around, but I
've been unable to get them working with batman-adv. So
266 instead, I started playing with a
267 <a href=
"http://www.raspberrypi.org/
">Raspberry Pi
</a
>, and tried to
268 get it working as a mesh node. My idea is to use it to create a mesh
269 node which function as a switch port, where everything connected to
270 the Raspberry Pi ethernet plug is connected (bridged) to the mesh
271 network. This allow me to hook a wifi base station like the Linksys
272 WRT54GL to the mesh by plugging it into a Raspberry Pi, and allow
273 non-mesh clients to hook up to the mesh. This in turn is useful for
274 Android phones using
<a href=
"http://servalproject.org/
">the Serval
275 Project
</a
> voip client, allowing every one around the playground to
276 phone and message each other for free. The reason is that Android
277 phones do not see ad-hoc wifi networks (they are filtered away from
278 the GUI view), and can not join the mesh without being rooted. But if
279 they are connected using a normal wifi base station, they can talk to
280 every client on the local network.
</p
>
282 <p
>To get this working, I
've created a debian package
283 <a href=
"https://github.com/petterreinholdtsen/meshfx-node
">meshfx-node
</a
>
285 <a href=
"https://github.com/petterreinholdtsen/meshfx-node/blob/master/build-rpi-mesh-node
">build-rpi-mesh-node
</a
>
286 to create the Raspberry Pi boot image. I
'm using Debian Jessie (and
287 not Raspbian), to get more control over the packages available.
288 Unfortunately a huge binary blob need to be inserted into the boot
289 image to get it booting, but I
'll ignore that for now. Also, as
290 Debian lack support for the CPU features available in the Raspberry
291 Pi, the system do not use the hardware floating point unit. I hope
292 the routing performance isn
't affected by the lack of hardware FPU
295 <p
>To create an image, run the following with a sudo enabled user
296 after inserting the target SD card into the build machine:
</p
>
299 % wget -O build-rpi-mesh-node \
300 https://raw.github.com/petterreinholdtsen/meshfx-node/master/build-rpi-mesh-node
301 % sudo bash -x ./build-rpi-mesh-node
> build.log
2>&1
302 % dd if=/root/rpi/rpi_basic_jessie_$(date +%Y%m%d).img of=/dev/mmcblk0 bs=
1M
304 </pre
></p
>
306 <p
>Booting with the resulting SD card on a Raspberry PI with a USB
307 wifi card inserted should give you a mesh node. At least it does for
308 me with a the wifi card I am using. The default mesh settings are the
309 ones used by the Oslo mesh project at Hackeriet, as I mentioned in
310 <a href=
"http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html
">an
311 earlier blog post about this mesh testing
</a
>.
</p
>
313 <p
>The mesh node was not horribly expensive either. I bought
314 everything over the counter in shops nearby. If I had ordered online
315 from the lowest bidder, the price should be significantly lower:
</p
>
317 <p
><table
>
319 <tr
><th
>Supplier
</th
><th
>Model
</th
><th
>NOK
</th
></tr
>
320 <tr
><td
>Teknikkmagasinet
</td
><td
>Raspberry Pi model B
</td
><td
>349.90</td
></tr
>
321 <tr
><td
>Teknikkmagasinet
</td
><td
>Raspberry Pi type B case
</td
><td
>99.90</td
></tr
>
322 <tr
><td
>Lefdal
</td
><td
>Jensen Air:Link
25150</td
><td
>295.-
</td
></tr
>
323 <tr
><td
>Clas Ohlson
</td
><td
>Kingston
16 GB SD card
</td
><td
>199.-
</td
></tr
>
324 <tr
><td
>Total cost
</td
><td
></td
><td
>943.80</td
></tr
>
326 </table
></p
>
328 <p
>Now my mesh network at home consist of one laptop in the basement
329 connected to my production network, one Raspberry Pi node on the
1th
330 floor that can be seen by my neighbor across the park, and one
331 play-node I use to develop the image building script. And some times
332 I hook up my work horse laptop to the mesh to test it. I look forward
333 to figuring out what kind of latency the batman-adv setup will give,
334 and how much packet loss we will experience around the park. :)
</p
>
339 <title>Oslo community mesh network - with NUUG and Hackeriet at Hausmania
</title>
340 <link>http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html
</link>
341 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html
</guid>
342 <pubDate>Fri,
11 Oct
2013 14:
10:
00 +
0200</pubDate>
343 <description><p
>Wireless mesh networks are self organising and self healing
344 networks that can be used to connect computers across small and large
345 areas, depending on the radio technology used. Normal wifi equipment
346 can be used to create home made radio networks, and there are several
347 successful examples like
348 <a href=
"http://www.freifunk.net/
">Freifunk
</a
> and
349 <a href=
"http://www.awmn.net/
">Athens Wireless Metropolitan Network
</a
>
351 <a href=
"http://en.wikipedia.org/wiki/List_of_wireless_community_networks_by_region#Greece
">wikipedia
352 for a large list
</a
>) around the globe. To give you an idea how it
353 work, check out the nice overview of the Kiel Freifunk community which
354 can be seen from their
355 <a href=
"http://freifunk.in-kiel.de/ffmap/nodes.html
">dynamically
356 updated node graph and map
</a
>, where one can see how the mesh nodes
357 automatically handle routing and recover from nodes disappearing.
358 There is also a small community mesh network group in Oslo, Norway,
359 and that is the main topic of this blog post.
</p
>
361 <p
>I
've wanted to check out mesh networks for a while now, and hoped
362 to do it as part of my involvement with the
<a
363 href=
"http://www.nuug.no/
">NUUG member organisation
</a
> community, and
364 my recent involvement in
365 <a href=
"https://wiki.debian.org/FreedomBox
">the Freedombox project
</a
>
366 finally lead me to give mesh networks some priority, as I suspect a
367 Freedombox should use mesh networks to connect neighbours and family
368 when possible, given that most communication between people are
369 between those nearby (as shown for example by research on Facebook
370 communication patterns). It also allow people to communicate without
371 any central hub to tap into for those that want to listen in on the
372 private communication of citizens, which have become more and more
373 important over the years.
</p
>
375 <p
>So far I have only been able to find one group of people in Oslo
376 working on community mesh networks, over at the hack space
377 <a href=
"http://hackeriet.no/
">Hackeriet
</a
> at Husmania. They seem to
378 have started with some Freifunk based effort using OLSR, called
379 <a href=
"http://oslo.freifunk.net/index.php?title=Main_Page
">the Oslo
380 Freifunk project
</a
>, but that effort is now dead and the people
381 behind it have moved on to a batman-adv based system called
382 <a href=
"http://meshfx.org/trac
">meshfx
</a
>. Unfortunately the wiki
383 site for the Oslo Freifunk project is no longer possible to update to
384 reflect this fact, so the old project page can
't be updated to point to
385 the new project. A while back, the people at Hackeriet invited people
386 from the Freifunk community to Oslo to talk about mesh networks. I
387 came across this video where Hans Jørgen Lysglimt interview the
388 speakers about this talk (from
389 <a href=
"https://www.youtube.com/watch?v=N2Kd7CLkhSY
">youtube
</a
>):
</p
>
391 <p
><iframe width=
"420" height=
"315" src=
"https://www.youtube.com/embed/N2Kd7CLkhSY
" frameborder=
"0" allowfullscreen
></iframe
></p
>
393 <p
>I mentioned OLSR and batman-adv, which are mesh routing protocols.
394 There are heaps of different protocols, and I am still struggling to
395 figure out which one would be
"best
" for some definitions of best, but
396 given that the community mesh group in Oslo is so small, I believe it
397 is best to hook up with the existing one instead of trying to create a
398 completely different setup, and thus I have decided to focus on
399 batman-adv for now. It sure help me to know that the very cool
400 <a href=
"http://www.servalproject.org/
">Serval project in Australia
</a
>
401 is using batman-adv as their meshing technology when it create a self
402 organizing and self healing telephony system for disaster areas and
403 less industrialized communities. Check out this cool video presenting
405 <a href=
"https://www.youtube.com/watch?v=
30qNfzJCQOA
">youtube
</a
>):
</p
>
407 <p
><iframe width=
"560" height=
"315" src=
"https://www.youtube.com/embed/
30qNfzJCQOA
" frameborder=
"0" allowfullscreen
></iframe
></p
>
409 <p
>According to the wikipedia page on
410 <a href=
"http://en.wikipedia.org/wiki/Wireless_mesh_network
">Wireless
411 mesh network
</a
> there are around
70 competing schemes for routing
412 packets across mesh networks, and OLSR, B.A.T.M.A.N. and
413 B.A.T.M.A.N. advanced are protocols used by several free software
414 based community mesh networks.
</p
>
416 <p
>The batman-adv protocol is a bit special, as it provide layer
2
417 (as in ethernet ) routing, allowing ipv4 and ipv6 to work on the same
418 network. One way to think about it is that it provide a mesh based
419 vlan you can bridge to or handle like any other vlan connected to your
420 computer. The required drivers are already in the Linux kernel at
421 least since Debian Wheezy, and it is fairly easy to set up. A
422 <a href=
"http://www.open-mesh.org/projects/batman-adv/wiki/Quick-start-guide
">good
423 introduction
</a
> is available from the Open Mesh project. These are
424 the key settings needed to join the Oslo meshfx network:
</p
>
426 <p
><table
>
427 <tr
><th
>Setting
</th
><th
>Value
</th
></tr
>
428 <tr
><td
>Protocol / kernel module
</td
><td
>batman-adv
</td
></tr
>
429 <tr
><td
>ESSID
</td
><td
>meshfx@hackeriet
</td
></tr
>
430 <td
>Channel / Frequency
</td
><td
>11 /
2462</td
></tr
>
431 <td
>Cell ID
</td
><td
>02:BA:
00:
00:
00:
01</td
>
432 </table
></p
>
434 <p
>The reason for setting ad-hoc wifi Cell ID is to work around bugs
435 in firmware used in wifi card and wifi drivers. (See a nice post from
437 "<a href=
"http://tiebing.blogspot.no/
2009/
12/ad-hoc-cell-splitting-re-post-original.html
">Information
438 about cell-id splitting, stuck beacons, and failed IBSS merges!
</a
>
439 for details.) When these settings are activated and you have some
440 other mesh node nearby, your computer will be connected to the mesh
441 network and can communicate with any mesh node that is connected to
442 any of the nodes in your network of nodes. :)
</p
>
444 <p
>My initial plan was to reuse my old Linksys WRT54GL as a mesh node,
445 but that seem to be very hard, as I have not been able to locate a
446 firmware supporting batman-adv. If anyone know how to use that old
447 wifi access point with batman-adv these days, please let me know.
</p
>
449 <p
>If you find this project interesting and want to join, please join
450 us on IRC, either channel
451 <a href=
"irc://irc.freenode.net/#oslohackerspace
">#oslohackerspace
</a
>
452 or
<a href=
"irc://irc.freenode.net/#nuug
">#nuug
</a
> on
453 irc.freenode.net.
</p
>
455 <p
>While investigating mesh networks in Oslo, I came across an old
456 research paper from the university of Stavanger and Telenor Research
457 and Innovation called
458 <a href=
"http://folk.uio.no/paalee/publications/netrel-egeland-iswcs-
2008.pdf
">The
459 reliability of wireless backhaul mesh networks
</a
> and elsewhere
460 learned that Telenor have been experimenting with mesh networks at
461 Grünerløkka in Oslo. So mesh networks are also interesting for
462 commercial companies, even though Telenor discovered that it was hard
463 to figure out a good business plan for mesh networking and as far as I
464 know have closed down the experiment. Perhaps Telenor or others would
465 be interested in a cooperation?
</p
>
467 <p
><strong
>Update
2013-
10-
12</strong
>: I was just
468 <a href=
"http://lists.alioth.debian.org/pipermail/freedombox-discuss/
2013-October/
005900.html
">told
469 by the Serval project developers
</a
> that they no longer use
470 batman-adv (but are compatible with it), but their own crypto based
471 mesh system.
</p
>