Configuring User-Space Access Points with Remote Controller in Mininet-WiFi

[Jonas Tn]

Thank you for the opportunity to be part of this group!

I am working on creating a wireless topology using user-space APs. To do so, I installed BOFUSS using the following command: install -3f.

As a simple test, I ran the following command:

sudo mn --wifi --ap user --innamespace --controller=remote,ip=127.0.0.1,port=6653

In the screenshot, you can see that when running the command above, an interface ap1-eth0 is created to connect to the SDN controller (Floodlight) through c0-eth0. Both iperf and ping work well in this setup.  

However, when I try to create a custom topology using a Python script, I use the following Mininet setup:  

net = Mininet_wifi(controller=RemoteController, accessPoint=UserAP, link=wmediumd, wmediumd_mode=interference)

In the creation of the access point, I pass the argument inNamespace=True.

Below is a screenshot that describes what I have created with my custom script:

The issue is that in this setup, the ap1-eth0 interface, which I expected to be connected to the controller like in the previous screenshot, is no longer visible. While ping works fine, iperf does not.

I believe there are some settings I might be missing, but I'm not sure what they are.

I want to create a Mininet script that replicates the command: sudo mn --wifi --ap user --innamespace --controller=remote,ip=127.0.0.1,port=6653

Thank you very much.

[Ramon Fontes]

Hello,

Did you notice any useful information when running the code at debug level?

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[Jonas Tn]

I recently ran the following command at the debug level:

sudo mn --wifi --ap user --innamespace --controller=remote,ip=127.0.0.1,port=6653 -v debug

The debug output provided some valuable insights. Specifically, I observed that a link was created between the access point and the controller by creating two interfaces: ap1-eth0 and c0-eth0, each with their IP addresses. The relevant lines from the output were:

c0 <-> ap1*** ap1 : ('ip link add name ap1-eth0 type veth peer name c0-eth0 netns 8269',)

added intf ap1-eth0 (0) to node ap1

moving ap1-eth0 into namespace for ap1

*** ap1 : ('ifconfig', 'ap1-eth0', 'up')

added intf c0-eth0 (0) to node c0

*** c0 : ('ifconfig', 'c0-eth0', 'up')

*** c0 : ('ifconfig', 'c0-eth0', '192.168.123.1/16')

*** ap1 : ('ifconfig', 'ap1-eth0', '192.168.123.2/16')

*** c0 : ('route add -host', '192.168.123.2', 'dev', <Intf c0-eth0>)

*** ap1 : ('route add -host', '192.168.123.1', 'dev', <Intf ap1-eth0>)

However, when I run my custom Python Mininet script using cls=UserAP and inNamespace=True with net.addAccessPoint, the automatic creation of this link does not occur.

From what I understand, I may need to manually create the link between the AP and the controller (c0) within my script, and also manually assign the IP addresses. I am reaching out to confirm if this is indeed the correct approach, as I have not found detailed guidance on this matter. Additionally, is there any comprehensive documentation available for BOFUSS that could assist with these tasks? 

Thank you

[Ramon Fontes]

You have to add a host and the controller must be running on it. You can find some directions on this mailing list as well as the mininet mailing list.

[Jonas Tn]

Does working with BOFUSS involve running the controller on a host?

[Ramon Fontes]

> Does working with BOFUSS involve running the controller on a host?

It's mandatory with in-band scenarios.

[Ramon Fontes]

Host in this setup means mininet host--the virtual one!

[Jonas Tn]

Thank you very much, Mr. Ramon. My goal is to implement and work with WPA2 and 802.11r handover. I understand that WPA2 has been designed primarily to work with user-space Access Points rather than kernel-based ones. For this reason, I am aiming to set up the configuration as described below

[Ramon Fontes]

It works well with OVS if you set datapath='user', as you can see at https://github.com/intrig-unicamp/mininet-wifi/blob/master/examples/authentication.py

[Jonas Tn]

Thank you Mr. Ramon. While I have been able to perform pings using OVS with datapath=user, I am encountering issues with iperf not functioning between stations. This has led me to consider working with user-space Access Points as a potential solution