Check your Internet connection for Business Voice

Business Voice is located in the cloud with Microsoft 365. Every device that uses Microsoft Teams and Business Voice needs a connection to the Internet.

To get the best Business Voice experience, you need a broadband Internet connection that can support the maximum number of phone calls that your organization might make at any one time. You also need to make sure that the computers on your network can reach Microsoft 365 servers.

To follow these steps, you need to have a tenant with one of the following subscriptions:

  • Microsoft 365 Business Basic
  • Microsoft 365 Business Standard
  • Office 365 E1
  • Office 365 E3
  • Office 365 F1
  • Microsoft 365 A1
  • Microsoft 365 A3
  • Microsoft 365 E3
  • Microsoft 365 Business

You don't need a Business Voice license to follow these steps.

Check your Internet connection speed

This article helps determine whether your Internet connection is fast enough for the number of people who need to make phone calls and host video conferences. You'll provide information about your organization and get back a report that shows how much of your Internet connection will be used by Teams and Business Voice.

Gather information about your Internet connection and users

Before you start, you need the following information:

  • The speed of your Internet connection
  • How many people will use Business Voice mainly from your office
  • How many people will use Business Voice mainly from a remote location, such as a home office

Enter your information into the network planner

Follow these steps:

  1. In a browser, go to Sign in by using an account that has Global Administrator permissions. The account that you used to sign up for Microsoft 365 or Office 365 has these permissions.

  2. Open Planning and select Network planner.

  3. Under Network plans, select Add. Enter a name for your plan, and then select Apply. Your network plan should look like this:

    Network planner main screen

  4. Select the name of your network plan. (It's Main office in the preceding picture.)

  5. On the next page, select Add a network site on the Network sites tab.

  6. Fill in only the fields that are indicated in the following screenshot, and then select Save. Leave the other fields on this screen blank, and don't select the ExpressRoute or Connected to WAN options.

    Network planner site information

  7. On the Report tab, select Start a report.

  8. Enter the following information, and then select Generate report to create a report that shows the bandwidth requirements for Teams. We show you how to read the report in the next section.

    Network planner report information

Find your minimum Internet connection speed

When you select Generate report, Microsoft 365 or Office 365 creates a report that looks like this:

Network planner report detail

The highlighted number shows how much of your Internet connection Teams and Business Voice will use. We recommend that this number is no more than 30 percent of your total Internet connection speed. For example, if your Internet connection is 60 Mbps, Teams and Business Voice should use no more than 18 Mbps.

Use this equation to determine your minimum Internet connection speed: <highlighted number> / 0.3. With the number that's highlighted in the preceding image, the calculation is 4.6875 / 0.3 = 15.6. In this case, the Internet connection speed should be at least 15.6 Mbps.

If Teams and Business Voice will use more than 30 percent of your total Internet connection speed, the highlighted number will appear red. In that case, you may need to upgrade your Internet connection.

Connection speed warning

Make sure the computers and devices on your network can reach Microsoft 365

Computers and devices that use Business Voice must use specific network ports to communicate with Microsoft 365 servers. These ports are essentially doors through which devices talk to each other over a network or the Internet. Your firewall needs to allow devices on your network to reach Microsoft 365 through the following outbound network ports:

  • TCP ports 80 and 443
  • UDP ports 3478, 3479, 3480, and 3481

The easiest way to check whether your firewall allows communication on these network ports is to make a test call in Teams:

  1. Go to on a computer on your network and install Teams. Make sure that the computer has speakers and a microphone.

  2. Open Teams and sign in by using a Microsoft 365 account.

  3. In Teams, select your profile picture, and then go to Settings > Devices.

  4. Under Audio devices, select Make a test call.

  5. Follow the steps to leave a message and have it played back to you.

    • If the call connects and you hear your message, your firewall is set up correctly.
    • If the call connects, but you can't hear the instructions or your message, make sure that your speakers and microphone are set up correctly, and then try again.
    • If the call doesn't connect or it connects but you can't hear your message, you might need to update your firewall to allow access to the required network ports. Check your firewall's documentation, or contact an IT specialist for help.

If you're an IT professional and want more information about how to prepare larger or more complex networks to support Business Voice, see Evaluate my environment. This article provides information about bandwidth, proxy and firewall requirements, and how to use the Network Assessment Tool to test your network.