How Does Audio Work on VoIP?

How Does Audio Work on VoIP?


Audio Issues (Bad Call Quality)

To understand how audio issues can occur, we must first understand how calls through VoIP work.

How does Audio Work?
  • Every VoIP call opens two separate channels; these are the SIP and RTP channels.
  • The SIP, or Session Initiation Protocol, is the ‘managing’ channel. When you place a call, the SIP will try to connect with the other side of the call to make sure that the foreign device is ready and able to take the call. SIP will look for things such as if the other device is already on a call or maybe has been set to Do Not Disturb and it will report back any errors it finds if there are any.
  • If all goes well then the SIP channel will connect both ends of the call and the RTP channel will start up to carry the actual audio that gets transmitted both ways.

The SIP and RTP channels operate independently,

  • The SIP and RTP channels operate independently, and the RTP channel even has different sub-channels for the different directions of the audio traffic.

What Role Does Voys Play?

  • We at Voys don’t carry the RTP channel on our network, instead when you make a call the RTP channel is established directly between you and the person you are calling. This makes for a faster and more direct connection instead of having to take a detour through our network first.
  • So what does it mean when an audio issue occurs?
  • It means that the direct channel between yourself and the person you are calling is being interfered with at some point between the both of you, but we can immediately rule out any issue on the Voys side as we are not involved with the actual audio of a call.
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