wifi networks with multiple aps

[guzh...@gmail.com]

Hello all,

I would like to simulate a wifi network with multiple APs operating at the same band. 

Is there any example that I can start with. Also, how to setup which AP will a STA connect to in the multi-ap case, especially when the STA is moving around.

It would be appreciated if anyone can give some hits on this. Thanks a lot!

Regards,

Zhouyou

 

[Tom Henderson]

On 5/8/22 20:57, guzh...@gmail.com wrote:

Hello all,

I would like to simulate a wifi network with multiple APs operating at the same band. 

Is there any example that I can start with.

I don't think there is one in the examples directory, but you can try to take an existing example and add an AP.

However, there is no roaming support in the AP, so if you want to connect the multi-AP network to an outside IP network, you will have to figure out an IP routing technique to ensure that packets from outside of the Wi-Fi network are sent to the correct AP (the one that associates with the STA of interest).

Also, how to setup which AP will a STA connect to in the multi-ap case, especially when the STA is moving around.

See https://www.nsnam.org/docs/release/3.36/models/html/wifi-design.html#infrastructure-association

If the STA hears beacons from multiple AP on the same SSID, it will wait for a period of time (StaWifiMac::WaitBeaconTimeout, default 120 ms) and then select the AP with the strongest beacon SNR.

If the STA moves and loses association, it will repeat the process.

It would be appreciated if anyone can give some hits on this. Thanks a lot!

Regards,

Zhouyou

 

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[guzh...@gmail.com]

Thank you Tom for ur fast reply and ur point to point explanation.

One more thing to ask here.

If I only need uplinks where all STAs are sending packets to a single sink via multiple APs. Do you think the routing is still needed or not?

In such a case, an AP just need to capture the packets sent by the STAs that it is associated with, and then forward packets to the sink.

[Ahmed Hasan Ansari]

Hi Tom,

I had a related question to your above explanation. I have a network with 2 APs and 1 wireless station connected to each AP. But it seems that the stations only receive beacons from the AP with which they share same SSID/BSS. Shouldn't they receive beacons from the other AP as well right at the start when they start to scan fro APs? 

I am using the StaWifiMac::StartScanning and StaWifiMac::ScanningTimeout to check this.

Thanks,

Ahmed Hasan Ansari