Hardware platforms of a Freifunk network

This post is part of the series Building your own Software Defined Network with Linux and Open Source Tools and covers the hardware platforms used within the backbone network infrastructure.

In the early days into the project we didn’t have much funds but thankfully received quite some donations in terms of old hardware as well as money. As we were young and didn’t know what we know today, we went down quite some different roads, made lots of experiences along the way, eventually reaching the setup we have today. This posts lists most the platforms we used within the last years, basically only leaving out early wireless platforms and sponsored server machines.

As most Freifunk communities rely heavily on products from the portfolio of Ubiquiti Networks, quite some devices will be covered. In the following I will just call them ubnt.

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Custom Links in Netbox – Shortcut to device WebUI/IPMI

Netbox allows to create Custom Links to a number of models for a while now. I’ve been reminded of that feature quite recently and follow the idea to have a direct link on the device page which leads to the management interface of that device.

In the Freifunk Hochstift environment we have a number of wireless backbone links which happen to have issues now and then and require some love in that case. As we use lots of Ubnt gear that love has to be applied via the Web interface of the device which is reachable via the management IP, which is configured as the primary IP of the device in Netbox.

Up to now this meant searching for the device in Netbox and copy the IP address of the device in the browsers URL bar and hit return. This can be achieved much nicer with a custom link which directly points to https://primary_ip and is accessible via a button on the device page.

This can be achieved by creating a Custom Link in Netbox (Customization -> Custom Link) for the appropriate Content Type, Link text + URL. As the intention is to add a Custom Link to wireless backbone devices, the appropriate Content Type is DCIM > device. Button class allows to configure the color of the button.

Using a little Jinja2 in the Link text it’s possible to only show this link on WBBL devices and certain switches: If the expression(s) given there renders as empty text the link will not be shown. My first instinct was to check for the device role and manufacturer:

{% if obj.device_role.slug == 'wbbl' or
      obj.device_type.manufacturer.slug == 'netonix'
%}
WebUI
{% endif %}

But checking for the platforms makes more sense as that’s the primary indicator for the devices which are managed via a web interface and they may be used in different roles (we have wireless local links too for example):

{% if obj.platform.name in [ 'AirOS', 'Netonix' ] %}
WebUI
{% endif %}

As shown above the device or “thing” referenced by the Content Type is represented via the obj object and it’s attributes are directly accessible. A look into the API representation or the Django model(s) of the device (or “thing” for that matter) may help to figure out the correct name.

What I did not find in the docs nor API nor model is that how you can access the IP part of an IP address, which in Netbox always carries the netmask. While searching I stumbled across an issue and learned that the following is possible:

https://{{ obj.primary_ip4.address.ip }}

Netbox also allows to group custom links within a drop down. All links sharing the same Group name will show up in a drop down named like the group.

With those pieces it’s easily possible to create custom links for special devices which point to the primary IP and provide the OPS team with a few clicks solution in case of trouble. Thanks to Tim for the hint 🙂

Deploying a Freifunk Hochstift backbone POP with Netbox Scripts

Some weeks ago Network to Code held the first (virtual) Netbox Day (YouTube playlist, Slides repo on github). John Anderson gave a great NetBox Extensibility Overview and introduced me to Netbox Scripts (Video, Slide deck, Slide 28) which allow to add custom Python code to add own procedures to netbox. I was hooked. About three to four hours of fiddling, digging through the docs, and some hundred lines of Python later I had put together a procedure to provision a complete Freifunk Hochstift Backbone POP within Netbox according to our design. I’m going to share my proof of concept code here and  walk you through the key parts of the script.

Netbox scripts provide a great and really simple interface to codify procedures and design principles which apply to your infrastructure and fire up complex network setups within netbox by just entering a set of config parameters in a form like the following and a click of one button.

Provision Backbone POP form
Provision Backbone POP form

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Topology of a Freifunk network

This post is part of the series Building your own Software Defined Network with Linux and Open Source Tools and covers the re-designed topology of the distributed infrastructure.

From a birds eye perspective, the Freifunk Hochstift infrastructure mainly consists of three building blocks:

  1. Distributed servers hosted across Germany providing infrastructure services
  2. Wireless backbones within the city of Paderborn, Warburg, etc.
  3. Freifunk nodes at homes, shops, enterprises, or elsewhere

This post will focus on the distributed servers as well as the wireless backbones and will only cover the around 1.000 client nodes from the perspective of connecting them to the backbone (“gateways“).

With all the things mentions in Specifics and history of a Freifunk network in mind I got back to the drawing board and thought about a new design.

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Specifics and history of a Freifunk network

This post is part of the series Building your own Software Defined Network with Linux and Open Source Tools and covers the specifics of a Freifunk network as well as the history for the Freifunk Hochstift network which led to the latest re-design.

From a birds eye perspective, the Freifunk Hochstift infrastructure mainly consists of three building blocks:

  1. Distributed servers hosted across Germany providing infrastructure services
  2. Wireless backbones within the city of Paderborn, Warburg, etc.
  3. Freifunk nodes at homes, shops, enterprises, or elsewhere

This post will focus on the distributed servers as well as the wireless backbones and will only cover the around 1.000 client nodes from the perspective of connecting them to the backbone (“gateways“).

Continue reading Specifics and history of a Freifunk network

Building your own Software Defined Network with Linux and Open Source Tools

Nearly two years ago, I started thinking about a next generation design for the Freifunk Hochstift backbone infrastructure, motivated by the limits and design choices made before (we were young and didn’t know better.. or didn’t listen..).

This post is the starting point of a series of posts about building a software defined wireless ISP network with Linux, a fistful of Open Source tools and low cost hardware.

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