What is Jitter?

What Does Jitter Mean?

A technical definition of jitter is “any deviation in, or displacement of, the signal pulses in a high-frequency digital signal”. These deviations can occur in the amplitude of a fibre signal, the phase timing or the width of the signal pulse. 

On a more personal level, we’ve all experienced jitter in some form or another. Perhaps you were on a Teams call for work and you were struggling to connect. Or maybe you were on a phone call then the line suddenly drops. Hello South Africa, Sawabona, that’s jitter. 

The information for your internet connection is transported from servers to your computer via data packets (also called datagrams or payloads). Think of it as little parcels being delivered from one place to another. Jitter occurs when there is a delay in sending and receiving those data packets. The longer it takes the data packet to arrive the more it can have a negative impact on your video and audio quality. 

How does jitter impact you?

Jitter is more than just annoying. It can lead to lost clients, frustrated work colleagues, and an overall reduction in productivity. If you’re working from home, a significant amount of jitter can cause severe disruption to your daily work, waste a huge amount of your time, and may leave you wanting to head back to the office.

Common examples of jitter include:

• Delayed calls
• Dropped calls
• Static and echo
• Distorted audio

What is an acceptable jitter rating?

For video streaming to work effectively, jitter should remain below 30 ms. If this is higher than 30 ms I can start to create packet loss problems with audio quality variations. Packet loss should be no more than 1%.

How does jitter work in practice? – The MyBroadband Experiment 

MyBroadBand conducted a fascinating survey looking at the difference between two connections – a 100Mbps consumer fibre service, which costs R947 per month, and a 100Mbps business fibre service, which costs R4,599 per month. The results were astounding – the cheaper consumer fibre service at a 5th of the cost, outperformed the significantly more expensive business fibre service.

Business fibre is typically more expensive because it promises to offer better network quality which is drafted in its service level agreement (SLA). Business networks tend to offer in their SLA’s network redundancies (additional infrastructure in case of network device or path failure) and congestion ratios (The higher the contention ratio, the greater the number of users that may be trying to use the actual bandwidth at any one time).

Consumer fibre (fibre to the home) can do with the occasional hiccups. As much as we would like it, we don’t expect our home internet to be 100% perfect all of the time, so we tend to compromise and pay less for it.  The benefits of business fibre come at a cost. But is it really worth it? 

MyBroadband ran an experiment. They compared two fibre connections installed at offices in adjacent office blocks:

• Connection 1 – A 100Mbps consumer fibre connection using Afrihost’s Openserve service for R947 per month.
• Connection 2 – A 100Mbps business fibre connection using Cool Idea’s DFA package – a service costing R4,599 per month.

Here’s a bit more about their methodology. They ran the test starting Friday morning, while employees were using the line, and they continued through the weekend until Monday morning. They ran speed tests at 15-minute intervals. Three devices were used to mitigate any problems that might creep in from any single device. The results were astounding. 

The consumer had an average download speed of 95 Mbps, while the business line averaged only 60 Mbps. The business line had slightly higher upload speed, which was expected with a symmetrical line (100/100mbps business line vs. the 100/50 Mbps consumer line).