Regardless of whether its components come in the form of dedicated hardware (appliances) or software-based systems, configuration is crucial for the error-free functioning of a VoIP system. In addition to the signalling settings specified during the planning phase, the transmission method plays an important role in media streams. Applying a compression method can reduce the size of the data packets that contain voice information.

Errors in the configuration of the transmission method can lead to transmission problems. If an unsuitable method is used and voice information is compressed too much, the voice quality often deteriorates. If, however, a method that does not compress the data enough is selected, the stream of information will not be adequately reduced and the data network can become overloaded.