What is jitter and how to reduce it on VoIP

Did you ever experience when being on a call that all of a sudden the words start to be mixed around and part of the sentences are lost?

VoIP relies entirely on the internet connection, this is one of the reasons that makes it so affordable. However this can also have a downside, when your internet connection has a high amount of jitter, call quality is heavily affected.

The good news is, that jitter is easy to diagnose and troubleshoot.

How does VoIP work

The way VoIP works is by delivering pieces of conversation through the internet as data, this means that sound has to be converted into “packets”. 

Packets are pieces of data traveling through the network that become voice, these are sent in intervals and because of this, the information is not necessarily sent in the same order as how it is spoken. 

Sometimes certain packets reach the recipient quicker than other packets, due to network interference or congestion.

Since VoIP relies on your internet connection, if the connection does not have good quality, it can lead to what is known as jitter, or even packet loss.

What is jitter

Jitter is a measure for the amount of packets of information that are dropped, or sent out of order, leading to a jumbled conversation. 

This means that the information arrives at the recipient’s line out of order and packages will not be received in the same order in which they are sent.

If the jitter is beyond 40 or 50 milliseconds delay, your call quality will degrade massively.

What causes jitter

Determining the exact cause for the jitter may not be easy, however, it normally comes down to the quality of the internet connection.

Anything that interferes with it will also affect your VoIP quality. To mention a few: 

• Network congestion: the most common cause of jitter is an overcrowded network. If there are many devices connected all being used at the same time the bandwidth is exhausted. Insufficient bandwidth leads to packets being dropped or delivered out of order.
• Wireless network: although the quality of WiFi is enough for our mobile phones, it is not necessarily powerful and stable enough to rely on for phone calls, always connect to the internet via cable.
• Poor hardware: bad quality hardware like an outdated modem, damaged Ethernet cable or a misconfigured router can cause issues.

To know how much jitter you have and the upload and download speed of your internet connection you can carry out this quick test.

How to reduce it

There are a few courses of action you can take to troubleshoot jitter:

• Upgrade your internet connection: this is the main factor, ensure you have a substantial upload and download speed capable of handling VoIP calls, as well as a stable connection without delays. This will generally be dictated by the Internet Service Provider you choose, and the speed of internet you purchase.
• Use a jitter buffer: a jitter buffer will “collect” the packets, and deliver them in order to prevent any from arriving too soon or too late. This “buffer” ensures packets are delivered perfectly every time.
• Upgrade network hardware: for example, purchasing a router with specific VoIP quality of service settings can help ensure that voice data is prioritized over other forms, preventing any jitter issues from occurring.