Third radio Connectivity tests with Arista APs.

For a WiFi Network administrator, it is a necessary task to keep checking the network health of the APs. Most of the management planes show the health of the AP which includes information like AP’s uptime, AP RF status, 802.11 authentications or association status, etc. Arista does the same by the tool called Cloud Vision WiFi. However, debugging WiFi Connectivity and performance issues becomes challenging when trying to do the same remotely. 

With the help of Arista AP’s third radio, a network administrator can achieve good enough information for troubleshooting any WiFi related connectivity or performance issues. Although the main functionality of this radio is to scan the environment for RF issues, a network administrator can leverage this radio for testing the connectivity and performance behavior on behalf of the WiFi client. 

The third radio of an Arista AP (eg. C-130, C-250, C-260) can connect to another AP in its vicinity and check the performance. Most of the issues could be debugged remotely using this radio in the client (WiFi) mode.

Functionality:

  • The third radio of Arista AP (eg. C-130, C-250, C-260) connects to another AP near its vicinity. 
  • The third radio can itself act as a WiFi supplicant and can connect to the APs nearby.
  • The radio can run predefined tests like association, authentication, VOIP, DHCP, DNS, Application Latencies, etc. 
  • We can schedule these tests OR run them on demand.

Functionality Example:

  • Lets say there are three Arista APs C-130 deployed. All these three APs have the support for third Radio. These APs would be named AP1, AP2 and AP3.
  • There have been users complaining regarding the performance and connectivity issues with respect to AP2.
  • Based on the Heatmap, the closest AP to AP2 is AP3. So we convert the third radio of AP3 to connect to AP2 and perform Authentication, Association, DHCP, DNS and other application tests as per symptoms observed. 
  • From the results, we can possibly root cause the issue and apply a suitable fix.

Steps to set up a third Radio Client Connectivity Test in Arista Cloud Vision WiFi (CVW):

Step1: A layout of how the APs are deployed would come handy along with the heatmap. Heatmap would show which APs we can select that would be used to connect to the nearby APs and provide test results. 

Step2: We need to select on which AP we would want to run the tests on. We can identify a few APs using the same heatmap to which we would want this third radio to connect and execute connectivity tests.

Step3: Once we have identified the AP that will act as WiFi Client (supplicant) and the AP to which it will connect, we can go ahead with the configuration of the same on Cloud Vision WiFi. Navigate to the location where you want to perform OR schedule this test. 

Step4: Navigate to Troubleshoot > Client Connectivity Test > Add Test Profile

Step5: Provide Name of the Test Profile, Frequency in which the radio needs to get connected and SSID to which it should connect. After selecting the SSID, if the SSID is PSK based the Passphrase would get updated by itself. If it is an 802.1X SSID, you may need to enter username and password. Check the Applications OR Websites you want to test in the Application Tests section. WiFi and Internet Throughputs can also be tested. Save the profile Profile.

Step6: After saving, the profile would be created in the window and would show an option of “Run a Test”. A window will pop up to enter the name of the AP for which this test needs to be executed. Type the name of the AP and it will be shown in the drop-down list.

Note: The functionality example is just for reference, the AP names mentioned in the above illustration may not be as per the functionality example.

Step7: Once you select the AP to run the tests on, you need to select the AP that would be acting as the client to connect to the other AP. 

Step8: Click on the AP and then click on “Start”. The test will be executed for a certain amount of time depending on the number of tests configured. A small pop window as shown below will show the progress of the test:

Step9: Once the tests are completed, results can be viewed and actions can be taken accordingly based on the results. 

Reviewing Test Results:

Once the tests are completed, as per the above steps, we can check the results to understand where is the miss and how we can fix the same. You can open the test results as soon as the tests are completed, or the same can be browsed from the Troubleshooting > Connectivity Test > Results. Below are the sample results:

  • First half will show the test environment information.
  • Then WLAN results will follow. Authentication and Association.
  • Following WLAN, we would see Network Statistics like DHCP, DNS, Etc.
  • This is followed by WAN Latency and Application (Predefined Applications) Tests.
  • Finally we can check the average throughput.
  • UDP and TCP tests are done with respect to the AP itself. However as seen Internet if shown as failed. So we can from here identify where the problem is and apply a possible fix. Mostly the issue here in this example is with the uplink port OR VLAN from where it is not able to communicate.

Advantages:

  • Information like association, authentication or network failures can be detected remotely by running these tests. Based on the messages, we can very well review the results and accordingly apply a suitable action/fix.
  • We can schedule tests. An administrator can start his day by analyzing the test results and can take pro-active actions if any issues are identified. This can be done with the help of scheduling. Navigate to Troubleshoot > Client Connectivity Test > Schedules > Select the dates when you want to run the tests and Map the test profile:
  • Results are stored. They can be revisited by navigating to Navigate to Troubleshoot > Client Connectivity Test > Results.

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