VOIP Latency

VOIP Latency – It’s Impact & Ways to Resolve It


Do you know that latency plays a great role in ensuring that your communication is smooth and uninterrupted? In a layman’s tongue, latency is the delay in sending and receiving the message on your network. To enjoy communication and various apps on your phone, the latency should be low so that you can play online games or do voice/video calls seamlessly!

When we talk about VOIP (Voice Over Internet Protocol) latency, it refers to the time taken by the voice packet to reach its destination. Hence, if the latency is high, your message will be transmitted slowly! While the expected latency is less than 150 ms, the acceptable jitter is below 30 ms.

VOIP latency is a vast topic in technology. Keep reading to know more about VOIP latency and its different aspects.

What is VOIP Latency?

In simpler language, the VOIP latency is a small delay during the transition of the data from one system to another. These are the glitches that happen for a few milliseconds during phone calls. High latency refers to more delays in communication and low latency means fewer delays.

Since VOIP calls are real-time, it is easy to notice any delay. When there is high latency, it is very difficult to communicate as it causes echo and the person on the other side wouldn’t be able to comprehend and may end up cutting the call.

As per a survey by IDC, 9 out of 10 executives think that the success of the business depends on low latency. Also, global business leaders rate latency as a priority over speed. This data makes a lot of sense, because in many businesses like call centers, high latency can directly impact call quality and may result in bad user experience.

To maintain a high-quality VOIP, it is important to –

  • Have a good internet connection.
  • The receiver should have a smooth internet connection.
  • The connection during the transmission should be smooth.

How is Latency Measured?

Latency is measured in two different ways, i.e. One-direction latency and round-way latency. The measuring unit is milliseconds (ms), which is one thousand of a second.

For VOIP calls, 20 ms latency is considered normal while 150 ms latency is hardly noticeable and is easily acceptable. However, if the latency goes beyond this, it drastically affects the call quality. A latency of 300 ms or higher is unacceptable.

One-direction Latency: This latency is the time taken by the packet to reach from the source to the destination.

Round-trip Latency: It is the time taken by the packet to reach the destination and the acknowledgement from the destination back to the source.

You can also calculate latency by subtracting the start time from the last time. You can repeat this calculation several times to get an idea about the average latency. Apart from this, various network diagnostic tools can be used to check the connectivity between servers.

Impact of Latency on Voice Calls

It is well understood that high latency could drastically affect the call quality.

  • Latency can cause slow and interrupted conversations.
  • You may also experience overlapping noises that hinder smooth conversations.
  • Latency may also cause eco.
  • While video conferencing, high latency may result in difficulty synchronizing between voice and other data.
  • Latency can alleviate communication bandwidth.
  • It may also result in more lag, which is very annoying especially if you are playing an online game.

VOIP Latency — Causes and Solutions
We’ve understood how latency can affect communication but not many of us know what the main causes of latency are and how we can manage it.

Insufficient Bandwidth

When there is insufficient bandwidth and low connection, the data packs take longer to flow, which causes low quality. In that scenario, the packet comes in the wrong order which takes a long time for reassembly till the time the order is restored.

Wrong Codecs

Codecs are the programmes which are used to encode voice signals to digital data so that it can be transmitted over the network. Your service provider may use the wrong one, however, in the case of VOIP apps you can tweak the codec and change them.

Firewall Software

Constant checks by the Firewall software may result in lag and hinder communication. In case you are facing a lot of issues related to Firewall, make sure that it allows clearance.

Old Hardware

A cellular network may not work with old hardware and may cause issues and result in latency and delays. This can be resolved by opting for a new telephone adaptor. Things like headsets may also add to high latency.


This may happen when there is a difference in the time of transmission and reception. Buffering is an issue when you are video streaming or listening to a song. For this, it is important to get in touch with your service provider and get a superfast connection with a 5G mobile plan.

Distance between Hardware & Software

It is a fact that the data packets travel long distances from the source to the end users. The farther the distance, the longer the receiving time will be, hence, the latency will also be high.

Network Congestion

In some cases, due to network congestion, there may be an incidence of high latency. Peak timings, large file transfer, and traffic spikes may result in network congestion. Hence, you have to understand the cause and use the internet accordingly so that you face fewer issues.


VOIP latency is very annoying especially while communicating with your friends and colleagues. The main effect of latency is a problematic internet connection with call lags, buffering, network congestion, and interrupted communication. There are many different ways you can measure VOIP latency like one-direction latency and round-trip latency. Once you know how to measure latency, you can understand the different reasons and solutions to counteract the issue of latency. This may include switching to a higher mobile plan and avoiding peak hours when the network congestion is seemingly high.

Once you understand the reasons for latency, you can easily rectify them by opting for solutions that can do wonders and ensure a great user experience.


What is an acceptable latency for VOIP?

In general, VOIP latency is measured in milliseconds (ms). While the normal latency of VOIP calls is 20 ms, the latency higher than 300 ms is completely unacceptable. However, if we talk about the acceptable latency, it is something around 150 ms as it is not really noticeable and can be ignored.

What do you need for VOIP to optimize latency?

There are different things that you can do to optimize latency for VOIP such as finding an appropriate bandwidth, prioritizing VOIP traffic, changing in routing, upgrade of network hardware, etc. By choosing the right service network providers, implementing latency tests, enhancing your routing, and replacing slow networking equipment and devices, you can reduce the high latency.

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