SIPTRUNK BLOG

What is QoS and Why Does It Matter?

QoS is short for Quality of Service. It is a router setting that is critical to good quality audio over SIP trunks. To understand why it will make a big difference to your customers, it helps to think of your internet connection as a freeway. It is traveled by all kinds of cars going in each direction at different speeds. They each have a different urgency around reaching their destination. Maybe one guy has to be to work by 8:00 am, while the mini-van on its way to the zoo will get there when it gets there. Once in a while a cop will speed through with sirens blazing.

Information traveling over your client’s internet connection works the same way. All kinds of traffic, video, file downloads, applications, voice and regular old browsing all share the same bandwidth. Data hog applications like streaming video or big file downloads can cause a traffic jam. When this happens, voice calls over SIP can suffer from common audio quality problems called jitter and lag. Quality of Service on the router solves this problem by giving priority to the audio signal. It’s like instantly opening up a special lane just for your voice calls, only when and for how long it is necessary.

QoS is possible because of the packetized nature of data over the internet. It assigns a priority to each device and service on the network. It then throttles the amount of bandwidth each is allowed to consume depending on what it is trying to do and how fault-tolerant it is. If packet loss occurs during a file transfer, for example, they’ll be resent until all are received. This is no big deal because the file will be received as one whole package. With voice and video, however, the lost bits can’t be sent later because any loss will result in a noticeable lag or glitch that will make for an unpleasant user experience. When QoS is properly configured, it recognizes the different types of traffic, understands the relative importance of uninterrupted packet flow and prioritizes accordingly.

Some routers include the option of automated QoS handling. They automatically choose which traffic gets priority, putting video and voice ahead of file downloads, for instance. The intelligence behind each vendor’s QoS functionality varies according to the quality of the algorithm in use and the processor power available to run it.

High quality audio is crucial for your customers, so you will want to encourage them to invest in a router that supports QoS. Fortunately, most modern, business-quality routers have this capability, so it is likely that your customer just needs to have it configured. The router’s user guide or control panel should have details and instructions. We’re also happy to help.