Do I need to configure my router for QoS?

You will probably eventually need to configure your router for QoS (Quality of Service).

When you really start to get your money's worth out of your Internet connection and utilize all of the bandwidth you are paying for, you need to make sure that the VoIP packets are given priority. Otherwise the voice will start to get very disturbingly choppy, garbled and/or delayed.

Most Internet connections are asymetrical. That's the 'A' in 'ADSL'. And it means that most often before the voice quality of people talking to you starts to degrade as you hear it, that your voice to them will.

Only your really good friends will tell you. They might say "Whoa. There was a lot of packet loss when you were just speaking." What they mean can vary from "You were so garbled I couldn't make out a thing you were saying" to "There were a couple of dropouts and I could tell this was a VoIP packet switched call instead of a dedicated POTS circuit switched call."

In a truly professional system, noticeable problems are a not acceptable. If done properly, neither party should be able to tell the difference between the two types of calls. Well maybe they'll know it's VoIP because it sounds better!

So when you first turn on your system and there is no other traffic on your Internet connection, everything sounds great. But then someone starts using the connection to play games, watch 'YouTube' and everything goes downhill from there.