How much bandwidth for VoIP?

21st July 2018

With businesses choosing to replace their traditional phone system with VoIP (voice over internet protocol) services, one of the biggest challenges is making sure that you allocate enough bandwidth to your Internet phone services.

A question prospective customers ask us every day is “how much bandwidth do I need to make high-quality VoIP calls?”

What is bandwidth?How much bandwidth for VoIP?

Bandwidth is the data transfer rate of your Internet service. This is the amount of data that you’re able to transfer over your Internet service provider (ISP) during a certain amount of time. It’s important to know how much bandwidth you get from your ISP to successfully set up a VoIP system.

How does VoIP use bandwidth?

VoIP phone systems run entirely over the Internet. This means that your call quality is dependent on your service provider and Internet speed. If you have low bandwidth you may not be able to make high-quality phone calls or, in the worst case, install a system that cannot even send or receive any calls.

What do I need to consider?

We recommend that customers start by asking themselves a few questions such as the data upload speed and download speed that your Internet provider can deliver to you. Whether you’re using VoIP within a businessor a home you need to assess what are the other applications that consume data on your bandwidth. Are there any Quality of Service (QoS) settings that you can slightly tweak so that your Internet connection is optimised for VoIP?

To see if your Internet connection is optimised for the installation of a VoIP system you can do a speed test to see if it is too low or too inconsistent. Put it this way, nine times out of ten the reason that VoIP systems don’t work is because there is a network connection problem in your home or business.

Calculating the bandwidth required

The amount of bandwidth you need to run a successful service will come down to two main things: the number of concurrent calls you think your company will make and the codec that your VoIP provider uses. A codec refers to a device that encodes a digital data stream for transmission and then decodes it for playback.

For a standard VoIP phone line you’re usually required to have somewhere between 85-100kpbs of bandwidth per concurrent call. Sufficient bandwidth will ensure that you send and receive high-quality calls via your VoIP system, but there are also many routers that will allow you to prioritise voice calls on your data network. This prevents other applications from running on your Internet network to affect the quality.

As an example, ten concurrent users would require 1Mpbs (10 x 100 kpbs x safety margin). To be safe, allow for 5 to 10Mpbs up and down although we understand that every organisation is different and that cases can be reviewed on a one-to-one basis.

How to optimise your Quality of Service

As we’ve mentioned, high-quality voice calls are expected to be the norm for businesses using a VoIP system. However, sometimes the Quality of Service needs to be optimised to make sure that it remains consistent.

Using an online VoIP test will let you simulate a certain number of concurrent phone calls from your business so that you gain a better understanding of your network performance.

If your router has an Application Layer Gateway (ALG) function, you should make sure to disable this, as more often than not your router will be unable to handle the sheer amount of inbound voice packets. Of course, it’s worth checking with an expert before changing any of your configuration settings as to not compromise on security.

We hope that our guidelines have given you a better understanding of not only the purpose of bandwidth for VoIP but how to ensure that you have enough so that you can choose us for your next VoIP system.