Let’s Talk about Network Latency and QoS

Posted on May 31, 2020

Why you should prioritize voice traffic on your network

QoS, or quality of service, has always been important for digital communications. If you are using VoIP communications, it becomes critically important that your computers don’t use all your network bandwidth. If your computers start using all your network bandwidth there will be no bandwidth left for your telephone system. What if someone in accounting decides that they’re going to download huge files and they start using all the bandwidth on the network? When you go to make a phone call, you’re not going be able to make the call, or the quality will be very poor because all the bandwidth is being used by accounting to download their giant files.

The larger your company is the chances increase that more people will use up the bandwidth at unpredictable times. QoS allows you to prioritize network traffic so there is always bandwidth for phone calls. QoS can be configured in the switches and routers in your networking equipment. If you set your VoIP traffic to be more important than other computer communications, your switches and your routers will always make sure your VoIP traffic gets through. Other computer communications that are sending emails or downloading files aren’t affected by a slight delay. However, if you’re talking to somebody on the phone and there’s a delay when the call starts, it definitely affects the quality and flow of the phone conversation.

How to avoid delays, overtalking and echoing

Network latency is most important if you use a hosted VoIP server. Back in the old days when a lot of people had a PBX or a VoIP server located in the building where they worked, all the telephones, computers and the VoIP server we’re in the same building. Nowadays, the VoIP server can be in the cloud and all your computers and devices can connect to the VoIP server through the internet. This is when you need to make sure your internet network latency is not too high.

Network latency is the time it takes for a bit to get from one place to the next. So when somebody says “hello”, how long does it take for those bits to go from that VoIP server all the way to your building. You may not have ever thought about latency until you start using a VoIP. That’s because when you’re downloading files you don’t really notice how quickly everything happens. But when on a phone call, everything has to happen basically in real time.

When you start talking on a phone, the person on the other side has to start hearing what you’re saying. When they start talking you have to start hearing what they’re saying. If that doesn’t happen, you will start talking over each other. You can have a miserable experience if the timing is off and you start talking over them and they start talking over you. You don’t really know where you are in the conversation. There are ways to troubleshoot bad call audio that we’ve discussed in a previous blog post.

The network latency is how long it takes for the bits and bytes to get from point A to point B. A telephone call on a legacy phone network has a latency of 45 milliseconds. When you start talking it takes 45 milliseconds for your word to get from here to there, whether you’re talking to someone across town, or across the country, it takes 45 milliseconds for your words to get there.

On a VoIP call there is a little more leniency about this. You can have a 20 to 150 millisecond delay and still have a good communication with the people on either side. So when you start talking it takes anywhere between 20 to 150 milliseconds for your words to get from there to there. If latency is over 150 milliseconds, you’re going to have compromised phone experiences, and at 300 milliseconds it will be a terrible experience.

Learn more about how to optimize call quality.

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