Multi-hop mesh network in MIT campus

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How To

Ethernet configuration

  1. Plug your USB ethernet adapter into another PC (which does not have an active internet connection)
  2. Register to the MIT network (using your web browser)
  3. Plug the ethernet adapter back to your XO (and wait a few mins for your registration to take effect)

To verify that your XO is connected to the MIT network, run "ifconfig" in a terminal. One of the network addresses listed (usually the one for eth0) should start with 18.

To get a new IP address without rebooting:

ifdown eth0
ifup eth0

This should help if for some reason you want to update your IP address or one is not being assigned. You must of course already be registered with the MIT network.


If you update the XO operating system (using olpc-update), you need to reinstall Cerebro from scratch. You must have a working Ethernet connection to do this.

In a terminal:

su -
yum -y remove cerebro
yum -y install git python-setuptools python-devel
git clone git://
cd cerebro

Reboot to start Cerebro and the tracking client.

Starting cerebroui

Start the Terminal activity and type:


To stop cerebroui go back to the Terminal activity (repeated Alt+Tab) and press Ctrl+C

With Cerebro version 2.9.7 and later (July 23), you should use "cerebroui" instead of "./cerebroui".

Updating your laptop

  • press ctrl+alt+F1 (F1 is the Neighborhood key, with eight dots) to go into a console.
  • Make sure you are root and you are in the /root directory (your console prompt should be a # and "pwd" should return "/root").
  • Given that you have a valid IP address, please type the following:
cd cerebro
git pull

If you get the following errors:
fatal: Entry '' not uptodate. Cannot merge.
./install: No such file or directory
You need to delete so a new copy can be downloaded. In the same directory as before (/root/cerebro) type:

git pull

and everything should work.

People's hacks

To change your laptop's name (which others see in mesh view), or change the colors of your XO icon, go to Sugar Control Panel and go to the nickname and color sections. If you want to post your laptop's name so that other people in the study know that you are also in the study (and maybe a good person to try to chat/collaborate on a program with), list it here (completely optional). --Noah

  • You can change your Cerebro profile (the information displayed in the Cerebro UI) by editing /root/cerebro/gui/profile.
  • File storage (profile picture, shared files) is now /media/mmc2/tmp/cerebro/, not /tmp/cerebro/ as before.


We are establishing a network of XO laptops to run experiments on campus and we would like to have as many laptops in East Campus and Senior House as possible. Other people from around the campus will eventually participate also, so this may be a good chance to chat with other users directly and possibly make new friends!

Participation terms

Would you like to participate? You will be able to use the laptop as much as you want, in (almost) any way you want, as long as you feed it (with power that is) and don't break its connection to the rest of the network. This means that the laptop must be constantly connected over ethernet cable for remote access (mainly for software updates), while the wireless network is used for communication with other laptops.


The laptop will be the property of OLPC and you may be asked to return at any time.

Network layout

The network in the end will look something like this: Network layout

Currently the network is centered around buildings 62 and 64 (the two parallel buildings of East Campus), building E2 (Senior House) and E15 (Media Lab). There is a slight chance to achieve connectivity with building NE18 (OLPC at 1CC) and building E55 (Eastgate).

More laptops may be added, depending on availability and position in campus.