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Understanding Voice Over IP Jitter, Latency, and Packet Loss

The key to good VoIP call quality depends on a few factors such as jitter, latency, and packet loss. We discuss these elements below so you can ensure your business has strong and reliable VoIP quality for customer calls.

Understanding VoIP Call Quality: The Basics

Voice over IP or VoIP calls occur over the internet by transmitting voice or data packets from one user to their destination. On VoIP calls, your voice is transformed from analog to digital signals in data packets and is sent to your destination. Upon arrival, these packets are converted back to analog and the audio is heard. Data packets generally contain about 20 milliseconds of audio and this whole process occurs at lightning speed.

And while this process seems simple and straightforward, there are a few factors that can affect the quality of the call, interrupting it. Voice over IP call quality depends on keeping the following elements to a minimum:

  • Jitter
  • Latency
  • Packet loss

Let’s look at these issues more closely and ways to troubleshoot them.

Voice Over IP Jitter

For a VoIP or SIP call to take place successfully, data packets must be transmitted from one user to their destination. And these data packets travel through different paths before they reach the destination. As such, all data packets may not take the same path or time to arrive.

VoIP jitter refers to the data packets being delivered to the destination at irregular intervals instead of being delivered at the same time. In other words, one packet is delivered after the rest of the packet. This can lead to low VoIP call quality with missing or jumbled audio.

How to fix this issue?

Generally speaking, 30 milliseconds (or less) jitter is acceptable. However, more than that can lead to serious call quality issues, affecting your calls and customer care efforts. And so, to fix jitter issues, you must first check your network and ensure you have a good internet connection.

Another way to fix jitter issues is by using a jitter buffer. This is a space where packets are collected and stored. Then, they are sent out at regular intervals ensuring they move in the right order.

VoIP Latency

Voice over IP latency refers to lag or delay within the call. More specifically, it’s the delayed time between a caller speaking and the receiver hearing the audio. This lag or delay can lead to speakers talking over each other or echoes in the middle of the call.

It is also important to note that international calls may experience more latency than domestic or local calls. And while it is not desirable, users generally tend to accept latency in long-distance calls more than local ones.

How to fix this issue?

Latency does not necessarily affect VoIP call quality. However, it does make the caller experience less desirable, giving way to frustration and miscommunication.

Most of the time, latency is a result of network congestion, which also contributes to jitter. To combat this, you should prioritize voice over IP data ahead of other data transmitted across your network. And a high-quality VoIP router can help with this as well as other issues that may crop up within a VoIP phone system.

Voice Over IP Packet Loss

Understanding packet loss is pretty straightforward. It refers to data packets lost during transmission from one user to their destination. Packet loss occurs when:

  • Data packets are lost and never arrive at the destination
  • Packets arrive late and are discarded as a result
  • Packets contain errors and are discarded
  • High data packet loss which results in low VoIP call quality or missing pieces of audio.

When data packets go missing, communication between two parties is incomplete or unclear. Troubleshooting this issue is similar to fixing jitter and latency: check your network. Congested networks where multiple and large files are downloaded or uploaded or transferred can lead to packet loss. Therefore, to ensure low to no packet loss:

  1. Make sure you have enough bandwidth.
  2. Minimize network congestion (don’t stream videos or download music or send large email attachments).

Get a Reliable VoIP Provider

To ensure you do not suffer through these issues, it is important to find a VoIP number provider that can handle your voice over IP traffic. Learn more about our VoIP service by speaking with one of our experts today. Call us at 1 (877) 898 8646 or chat with us online for more information!

How to Measure and Improve VoIP Call Quality

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A well-functioning business VoIP system ensures that your business stays connected with customers and clients, no matter where you are located. But an important part of using VoIP numbers or a VoIP phone system is to make sure your call quality is efficient and not compromised. In this post, we will look at how to measure and improve VoIP call quality.

What Are the Most Common Issues With VoIP Call Quality?

Before we delve into how to measure your VoIP call quality, it is imperative to first understand what are the causes of poor VoIP quality. There are a few different factors affecting the quality of your voice over IP system. Fortunately, these VoIP issues are easy to fix.

So, what are the major causes of poor VoIP quality?

1. Latency

Latency refers to lag or delay that occurs between a speaker and receiver. In other words, there is a delay between the time the speaker says something and the receiver hears it. This results in echoes or speakers speaking over each other. While latency doesn’t affect the VoIP call quality, it does make it difficult to communicate effectively, leading to frustration and confusion.

2. Jitter

Jitter occurs when a data packet is delivered later than the rest of the packet. VoIP and SIP calls occur through the transmission of data packets from one user to the next. A data packet can take various paths through the interweb to reach its destination. Furthermore, all the packets may not take the same path which can lead to one or two packets arriving later than the rest. High levels of network jitter can result in bad VoIP call quality and missing or jumbled audio.

3. Packet loss

Packet loss refers to the loss of data packets during transmission. There are a few different types of packet loss:

  • Completely lost and never reaches the destination
  • Arrived late, therefore discarded
  • Contain errors, therefore discarded
  • High packet loss leads to bad call quality as pieces or chunks of audio are missed or are hard to decipher.

4. Poor internet connection

Since VoIP calls occur over the internet, having a strong internet connection is essential to the proper functioning of your business phone system. If your ISP is optimized merely for surfing the internet and uploading or downloading files, then you won’t have even bandwidth for speedy VoIP connections and transmission of data packets. You can use online speed testing tools to get a good understanding of your internet capabilities such as:’

  • Upload speeds
  • Download speeds
  • Jitter times, etc.

How is VoIP Quality Measured?

The Mean Opinion Score (MOS) is the leading tool to measure VoIP call quality. MOS measures subjective call quality and its scores range from 1 (bad VoIP quality) to 5 (excellent VoIP quality).

Some standards and metrics to consider when measuring VoIP include:

  • The ITU standards P.861 (PSQM) and P.862 that state how MOS scores should be calculated.
  • The ITU standard P.563 that calculates call quality passively and includes an R factor to estimate a MOS score.
  • PESQ and PAMS methods that need a license from Psytechnics.
  • Cisco IOS that has built-in tools to measure metrics and estimate MOS during test calls.

How Do I Test VoIP Quality?

In order to test VoIP call quality, you will have to monitor network latency, jitter, and packet loss. VoIP quality tests will enable close monitoring of calls. Call details, activity reports, and alerts can help you identify areas that need improvement or solutions.

What is a Good MOS Score?

MOS measures VoIP quality by assessing the user’s opinion of the call’s quality to score it. On a scale of 1 (bad) to 5 (excellent), a good score for VoIP calls falls between 3.5-4.2 range. This is what a MOS chart looks like:

MOS Quality Issue
5 Excellent Perfect quality
4 Good Less perfect; may include some loss of quality
3 Fair Slightly strained quality
2 Poor Strained quality
1 Bad Heavily strained quality

7 Ways to Improve VoIP Call Quality

So, how can you improve VoIP quality, and what are some helpful troubleshooting methods? Here is a list of 7 ways to fix your VoIP call quality:

1. Check your internet speed

The first step to ensuring high VoIP call quality is choosing the right internet service provider. Make sure you have enough bandwidth for VoIP calls and regularly test your internet speed using online testing tools.

2. Check network & equipment configuration

One of the top troubleshooting methods is to check if your network and equipment are properly configured. A network that is not properly configured can negatively affect call quality. This is especially true if you are transmitting voice and data.

3. De-jitter your VoIP

Jitter is often a result of network congestion, packet lags, configuration issues, etc. The best way to combat jitter is to invest in a de-jitter buffer such as a router or Edge device that receives a Real-Time Protocol (RTP).

4. Check your cabling

Most of the current cabling for phone communication and data transmission is a CAT 5 or higher. Ensure your phone system has the right wiring and cabling for its purpose.

5. Choose good handsets

Another quick and easy troubleshooting method is to get new and improved headsets. Low-quality headsets can easily hinder call quality and make simple communication difficult and unclear. Get good headsets for your employees so they have the best tools to work with.

6. Avoid hubs on your local access network (LAN)

A LAN with multiple hubs can result in low call quality. The recommendation is that each phone is individually connecting to the switch.

7. Determine whether “crackling” is because of faulty wiring or hardware problems

Lastly, if you are experiencing “crackling,” it is important to identify where it is coming from so you can fix it appropriately. Are all lines experiencing crackling? Are cords not properly or tightly plugged in? And so on.

Improve VoIP Quality and Enhance Business Communication

One of the top reasons why businesses are switching to Voice Over IP is because issues related to these phone systems are easy to identify and fix. Ready to switch to VoIP for business? Call us today to find out how our VoIP systems can benefit your business!