Dili Village Telco Part 6

Saturday, and we are doing a little more training with 6 people. Some simple exercises to teach these guys how to determine if a mesh link is OK. We are starting with people who worked through the introductory course last Monday.

The entire course can be abbreviated to:

Applications -> Accesories -> terminal
# sudo su -
# /etc/init.d/network-manager stop
# ifconfig eth0
# ifconfig eth0
# ssh
# ping
# ping -s 1400
# ping
# ping -s 1400

The node had a good link, the node was marginal. The long pings (-s 1400) showed up the bad link. The node is the Supernode. They logged into that first and ran the ping tests from there.

The Ubuntu network-manager can be a trap, it messes up your eth0 interface when it attempts to get an IP via dhcp. So I showed them how to switch network-manager off, however I imagine that line is just Linux-magic to them.

Coming from a developing world Windows background, it is hard to understand that a little white box 30m in the air can have a command line interface you can ssh into. For that matter it’s hard to understand ssh, or ifconfig, or a command line interface.

One pair of students stood out – a Cambodian sys-admin who is here helping out with the Univeristy Windows network, and his friend who (I think) was a Timorese Univeristy student with excellent English. They meticulously wrote every step down, then they took turns repeating the exercises multiple times.

Great to see such enthusiasm from people who have never used a Linux command line before. Such hunger to learn. If any of you want an adventure, these people will happily attend any IT course you can teach over here. Basic networking, database, web, anything would really help these guys get off the ground floor.

Ahh yes, nearly forgot to mention the network. We didn’t get close to my 24 hour uptime target. As I emerged from my hotel I saw the Blind Society node has spun around 180 degrees in the night! The boys fixed that fairly quickly. At about noon I noticed the batman scores wildly fluctuating and the ping performance had dropped. So I strolled around to the Blind Society to find the Nanostation again pointing a bit off path but also swaying nicely in the wind. The pole is fixed to the tree half way up and so moves with the wind! DOH! Probably OK for an omni but no good for a directional Nanostation.

After 7 days here strapping poles to trees is starting to seem normal to me.

The University node is only about 50m away and has a proper mast (with guy wires even) so we moved the Nanostation to there, leaving just the Mesh Potato on the Blind Society pole. Now we have received signal strengths of -45dBm between the Nanostations! At night they are glowing a dull red colour.

However still not a perfect link to the Blind Society MP, so I suspect lots of other Wifi in that area. I can see quite a few 8dB type omnis sticking up within a few 100m of that site.


Dili Village Telco Project Wiki
Dili Village Telco Part 1
Dili Village Telco Part 2
Dili Village Telco Part 3
Dili Village Telco Part 4
Dili Village Telco Part 5

3 thoughts on “Dili Village Telco Part 6”

  1. Keep up the good work, glad to hear that you are making progress. It’s interesting to read about the huge problem that the dense wireless activity is causing.

  2. I don’t get it. Why do you need to stop network-manager?

    If you’re stopping network-manager to stop it from configuring your network interface, then that’s completely the wrong way to go about it.

    N-M will automatically not configure an interface if you specified it in /etc/network/interfaces.

    So in /etc/network/interfaces put:

    auto eth0
    iface eth0 inet static

    Or, if you want to configure it via another method, but still have N-M ignore the interface, just use this instead:

    iface eth0 inet manual

    After you edit that file, N-M will stop configuring that interface once you run /etc/init.d/networking restart.

    VoilĂ .

  3. NM needs to be stopped to disable dhcp which is running by default. If we don’t disable it we find our static IPs get removed after a few minutes. After the PC is rebooted we want the interface to revert to dhcp, so we don’t want any permanent changes

    Jeremy, the people doing these exercises have never seen a command line before. To edit the N-M conf files as you describe would be way beyond them, I guarantee there would be errors. They would not know how to fix them. They would not know anyone who could fix them. They would not have the bandwidth or possibly English skills to seek a fix on the Web. They would not be able to use any Unix text editor. They would have no comprehension of what the N-M conf files were doing.

    They also need to be able to repeat these exercises on any vanilla Ubuntu install when I have stepped back onto the plane.

    So the key here in the developing world is to keep the sophistication to an absolute minimum. We all have to start somewhere…..

    – David

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