Bandwidth Availability and Requirements

Bandwidth availability plays an important role when using VoIP or WebRTC services. If you do not have enough bandwidth or available bandwidth when making calls, you might experience voice quality problems that could result in choppy voice, unexpected issues, and a poor user experience.

To determine how much of your current bandwidth is required to maintain good quality for voice calls, consider the following questions: 

  • What is the data upload and download speed that your Internet Service Provider (ISP) delivers? Your ISP can confirm what bandwidth you signed up for. ISPs generally refer to bandwidth as an "up to" value, as in "up to 50 Mbps" or "up to 150 Mbps".
  • What other services and applications on your network consume a portion of that available bandwidth? 
  • How many concurrent calls do you expect to receive in your contact center? 
  • What is your throughput? The best way to determine your bandwidth is to run a throughput test as recommended in Testing Network Bandwidth. You can also monitor your bandwidth throughput through your router or access layer 3 switches.
  • Are there Quality of Service (QoS) settings that you can adjust to optimize your network? 

Testing Network Bandwidth

Call centers that use webRTC technology need enough continuous bi-directional bandwidth to ensure call quality. For this reason, we recommend that you test your network connections.

  1. Log in to the platform using Skylight or Skylight Desktop.
  2. Complete the Twilio Network Speed test to determine maximum expected concurrent call volume.
  3. Use the following calculation to determine the minimum required bandwidth:

    Maximum expected concurrent call volume x 0.085 = Estimated bandwidth needed in MBPS.

    Example: _650_ concurrent calls x 0.085 = 55.25 MBPS

  4. Calculate a safety margin by multiplying the number of expected concurrent calls by 100 kbps.

    A safety margin ensures that you can sustain the required bandwidth, even when your Internet service falters.

  5. Complete a WebRTC troubleshooting test to determine if any other settings need to be reviewed.

For example, 10 concurrent users require 1 Mbps (10 x 100 kbps x safety margin), which means that you should allow for 5 to 10 Mbps both up and down. Depending on the other services and applications using your Internet connection and on the capabilities of your router, 3 to 5 Mbps may be sufficient, or you may need to increase your bandwidth.

This chart provides the bandwidth requirements for high quality voice performance.

Number of Concurrent Calls Minimum Required Bandwidth Recommended Speed

1

 100 Kbps Up and Down 3 Mbps Up and Down
3 300 Kbps Up and Down 3 Mbps Up and Down
5 500 Kbps Up and Down 5 Mbps Up and Down
10 1 Mbps Up and Down 5 - 10 Mbps Up and Down