Python – How to Connect to a Cisco WLC (Aireos)

November 12, 2020

This is a very simple article just explaining how you can connect to a Cisco WLC (aireos) using a python script.

You could use this as a first step in developing more advanced Python scripts to monitor or configure your Cisco Wireless Lan Controllers.

I am still learning Python so this might not be the only and easiest way to do it!
Note: starting with version 8.8, you could interact with your Cisco WLC in a easier way using YANG models. See this presentation from Cisco Live: https://www.ciscolive.com/c/dam/r/ciscolive/us/docs/2018/pdf/BRKEWN-2050.pdf

Prerequisites

We will assume that you have already Python installed on your computer. I would also advise you to use virtual environment when developing Python scripts on your computer.

Here is the tutorial I have followed in order to setup my laptop (macOS) for Python programming: https://developer.cisco.com/learning/lab/dev-mac/step/1

Here are the program and libraries we will be using here:

Python 3.7
netmiko

Here is how I setup a virtual environment for Python 3.7 on my laptop:

Here is how I installed the netmiko library within this new virtual environment:

Code – How To

Here is the Python code you will need to in order to connect via SSH to a Cisco WLC. Obviously you need to gather this information first:

IP address of the WLC
Username allowed to SSH into the WLC
Password associated with that user

#!/usr/bin/env python

from netmiko import ConnectHandler

with ConnectHandler(ip = '192.168.20.2',
                        port = 22,
                        username = 'admin',
                        password = 'Cisco123!',
                        device_type = 'cisco_wlc_ssh') as ch:
    print(ch.send_command("show ap summary"))

In this example, we are using the object called ConnectHandler from the netmiko library to establish an SSH connection to the WLC (192.168.20.2).

Once connected, we are sending the command “show ap summary” and we are displaying the output of this command.

Go a Step Further

Connecting to the Cisco WLC could be the first step in a more complex script. Therefore, I have done the following in order to ease the process:

Created a configuration file where I keep my WLC details (IP address, username and passwords)
Created a script that I called ssh_wlc.py that defines function that will establish the connection based on the WLC configuration file

I then re-use my script as a “library” whenever I work on a script and I need to connect to a Cisco WLC.

Note: Python 3.5+ is required here since we are using PEP 484 type hints.

Here is what my configuration file looks like (I used xml so it is easier to parse):

<?xml version ="1.0" encoding="UTF-8"?>
  <wlc>
    <name>SemFio-WLC</name>
    <company>SemFio Networks</company>
    <ipAddress>192.168.20.2</ipAddress>
    <username>admin</username>
    <password>Cisco123!</password>
    <ssh_port>22</ssh_port>
  </wlc>

Here is what my ssh_wlc.py script looks like:

#!/usr/bin/env python
#
# This script SSH into a network device defined in a configuration filename
# Configuration file: wlc.configuration
#
# This script can also be used as a library
#
# Written by @VergesFrancois

import xmltodict
from netmiko import ConnectHandler


''' Retreive the network device details from an XML config filename
    - Config file:  'wlc.config'
    - Returns:      A dict containing the device details
'''
def retrv_device_info(config_file: str) -> dict:
    with open(config_file, 'r') as file_object:
        xmlString = file_object.read()
        dom = xmltodict.parse(xmlString)

        device = {'name':dom['wlc']['name'],
            'address':dom['wlc']['ipAddress'],
            'username':dom['wlc']['username'],
            'password':dom['wlc']['password'],
            'ssh_port':dom['wlc']['ssh_port'],
            'device_type':'cisco_wlc_ssh'}

    return device


''' SSH into a WLC and send the 'show ap summary' command
    * Paramters
        - Device: Dict containing the device details
    * Returns
        - A str containing the output of the command
'''
def retrv_ap_summary(device: dict):
    print('** Connecting to {} ({})...'.format(device['name'],device['address']))

    with ConnectHandler(ip = device['address'],
                        port = device['ssh_port'],
                        username = device['username'],
                        password = device['password'],
                        device_type = device['device_type']) as ch:
        print('** The connection is open')
        command = "show ap summary"
        output =  ch.send_command(command)

    return output


def main():
    device = retrv_device_info('wlc.config')

if __name__ == "__main__":
    main()