Configure a Cisco Mobility Express AP for an APoS Site Survey

This article explains how to configure a Cisco Mobility Express AP for an AP-on-a-Stick site survey using the CLI (Command Line Interface). It is also possible to do it using the provisioning SSID.

Right before configuring the AP for the survey, I had to convert it from the CAPWAP mode to the Mobility Express mode.

Step 1 - Connect to the AP

Connect to the AP via the console port. (I use AirConsole on macOS)

Step 2 - Setup Wizard

​When the AP boots for the first time in the Mobility Express mode, you are presented with a setup wizard. We will use the wizard to configure the following parameters:

• IP address of the Mobility Express management interface: 192.168.88.11/24 (Note: The IP address of the Mobility Express controller has to be different from the AP IP address!!)
• IP address of the gateway: 192.168.88.1
• DHCP server for the Wi-Fi clients: 192.168.88.100-200
• Time
• Host name of the controller: surveyWLC
• Admin credentials: Admin / Cisco123

You will notice that I am not configuring any WLAN profile yet. This will come later.

​Here is how I configured mine (these parameters can be changed to match your environment):

Wait for the AP to reboot. You will be able to login into the controller using the admin username and the Cisco123 password.

Once everything is configured, here are a couple of useful show commands that you could use to validate your configurations:

• show interface summary
• show time
• show dhcp summary

Step 3 - Configure the survey SSIDs

When I do AP-on-a-stick site surveys I like to configure the following SSIDs:

• Open SSID called survey24 on the 2.4GHz band only
• Open SSID called survey5 on the 5GHz band only

Here is how you can configure them on the Mobility Express controller via CLI:

Once everything is configured, here are a couple of useful show commands that you could use to validate your configurations:

• show wlan summary
• show wlan wlan_id​

Step 4 - Radio Settings

I also like to keep control on the channel and transmit power used for the survey on both frequency bands. In this example, we are configuring the 2.4GHz radio on channel 1 with a transmit power level of 4 and the 5GHz radio on channel 36 with a transmit power level of 2.
Use the show config ap 802.11b ap_name and show config ap 802.11a ap_name commands to find out which power level corresponds to which dBm value for your AP.

First, you need to make sure that the AP joined the controller using the show ap summary command. In our case the name of the AP was surveyAP. If the AP didn't join, make sure that you are using different IP addresses for the AP and the Mobility Express controller. Also, check out this article from Packet 6: Troubleshoot AP Joining Issues - Cisco Mobility Express.

Here is how you can configure these radio settings on the Mobility Express controller via CLI:

Now, if you are using a Cisco Aironet 2800 or 3800 series AP, you will not have the 802.11b radio available. Instead, you will configure the 802.11-abgn radio.
If you try to configure the 802.11-abgn radio the same way we configured the 802.11b radio above, you will get the following error:

This is because, by default, the 802.11-abgn radio is set to the auto role.
We need to change the role to manual client-serving in order to be able to configure the custom transmit power. 

Here is how to configure the 802.11-abgn radio:

Once everything is configured, here are a couple of useful show commands that you could use to validate your configurations:

• show ap summary
• show advanced 802.11b summary
• show advanced 802.11-abgn summary
• show advancde 802.11a summary
• show ap config 802.11b ap_name
• show ap config 802.11-abgn ap_name
• show ap config 802.11a ap_name

Step 5 - Validations

You should now see both SSIDs being broadcasted by the AP.
As a validation, I try to associate to both SSIDs and wait to receive an IP address.

Here are a few commands that you could use on the Mobility Express controller to validate the client connections:

• show client summary
• show dhcp leases

Don't forget to save your configurations using the save config command.
You are all set!

Ressources

Here are a few useful and related links:

• Complete guide from Cisco: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_Cisco_Mobility_Express_Deployment_Guide/b_Cisco_Mobility_Express_Deployment_Guide_chapter_01101.pdf
• Mobility Express Command Line Interface document: ​https://www.cisco.com/c/en/us/td/docs/wireless/access_point/mob_exp/83/cmd-ref/me_cr_book.html
• Troubleshoot AP Joining Issues – Cisco Mobility Express: https://www.packet6.com/troubleshoot-ap-joining-issues-cisco-mobility-express/

Thank you for reading. Let me know how you do it!

Cheers'


written by François Vergès