IP audio transmission is the transport of audio (changing audio levels) that is in the form of data packets to a receiver through an IP data network. IP audio media may be downloaded completely before playing (file downloading), transferring as the audio is played (audio streaming) or played as soon as enough of the media has been transferred (progressive downloading).

IP packet transmission systems may include the use of flow controls that can define when media starts and stops. Bandwidth controls may also be used to adjust the amount of data that can be sent through the network as the transmission capacity of the data network changes (becomes congested). Bandwidth control can be used by the sender to change the amount of compression (lower quality when bandwidth is limited).

This figure shows how an audio server can adjust its data transmission rate to compensate for different audio streaming data rates. This example shows how an audio server is streaming packets to an end user (for an Internet audio player). Some of the packets are lost at the receiving end of the connection because of the access device. The receiving device (a multimedia PC) sends back control packets to the audio server, indicating that the communication session is experiencing a higher than desirable packet or frame loss rate. The audio server can use this information to change the amount of audio compression and data transmission rates to compensate for the slow user access link.