Running the Network Assessment tool

The Skype for Business Network Assessment tool provides a simple and comprehensive option to check the network performance and understand if your network is prepared for handling Skype for Business and Microsoft Teams calls.

Start with downloading from and run the installer:


Check where the software is installed:

C:\Program Files\Microsoft Skype for Business Network Assessment Tool

Or C:\Program Files (x86)\Microsoft Skype for Business Network Assessment Tool

(Later Edit: With the new Microsoft Teams Network assesment tool, the current path is “C:\Program Files (x86)\Microsoft Teams Network Assessment Tool\”)


Open Cmd and navigate to the appropriate folder:

Cd ”C:\Program Files (x86)\Microsoft Skype for Business Network Assessment Tool”

or for Teams: Cd “C:\Program Files (x86)\Microsoft Teams Network Assessment Tool\”

Run tool with .\NetworkAssessmentTool.exe

If requested, allow the executable in the Windows Firewall

You will be presented with the initial outputs of the test, containing network values.

For example:

Now, you can access

And you can compare the values obtained above with the reference values presented in the above article:

Metric Target
Latency (one way) < 50ms
Latency (RTT or Round-trip Time) < 100ms
Burst packet loss <10% during any 200ms interval
Packet loss <1% during any 15s interval
Packet inter-arrival Jitter <30ms during any 15s interval
Packet reorder <0.05% out-of-order packets


As a best practice advice, the assessment should be run 3 times:

  1. When customer is connected to wi-fi (see this quite a lot) -> lack of QOS might cause Call Quality issues
  2. When customer is connected with ethernet cable.
  3. When customer is connected to outside network where traffic is not passing through firewall performing blocking/inspection/packet analysis.


Tips and Tricks:

Running .\NetworkAssessmentTool.exe /connectivitycheck /verbose will display the ip addresses and ports against which tests are being performed. This is a good starting point to check if some ports are being blocked in your network.


O365 number in “Failed” status / AssignmentFailed

Obtaining numbers in Office365 is pretty straight-forward. Just go to the Skype for Business Admin Portal, navigate to Voice -> Phone Numbers and click on the big plus sign:

Now, aside the licensing pre-requisites I was talking about here, you will also have to have setup Emergency Locations.

I am not going to go through what are Emergency Locations since are very well explain at, however, note that:

  • In the US, an Emergency Location is required when assigning a phone number to a user.
  • In EMEA, an Emergency Location is required when acquiring the phone number from the portal or porting the number to Microsoft.

Also, I would like to emphasize on the Emergency Calling Terms and Conditions and to be more specific, Admins should communicate to all users with Calling Plans in Office 365 that although Calling Plans can be used anywhere in the world where an Internet connection is available, users should not make an Emergency Services call from a location outside their home country/region because the call likely will not be routed to the appropriate call center in that country/region.

Moving forward with acquiring phone numbers, it is very important to understand that in order to successfully activate a phone number in Office365, the address setup in the Emergency Location which you will use to acquire the number, must match the phone number’s area code.

For example, I can successfully create an Emergency Location for Barcelona and then use it to acquire a Madrid phone number, however, after the number being stuck in “Provisioning” state for a while, it will then fail to activate, changing its status to “Failed”:


Doing a quick lookup in powershell for phone numbers which are not in Active state, will lead us straight to our broken phone number:

Now if indeed you have a wrong Emergency Address set on this number and you would like to change it, please note that:

  • You can use the “Change” button for the Emergency address
  • You must also grant this number to a user, otherwise it will not allow you to Save your settings
  • Once you Activate your number with an Emergency Location, you can no longer change it by yourself. If indeed you have activated a number with a specific Emergency Location and you need to change it, then you must get in contact with ptneu[at]

Doing another query in PowerShell, i can now see the number changed its ActivationState from Assignment Failed, to Assignment Pending, and moreover, it is also displaying my tenantID along with the ObjectID of the user to whom i’ve assigned it:

Fast forward through the night and querying the number again, I can see it both in the portal and PowerShell that now is activated: