Voice over packets and video conferences

Inexpensive video cameras and audio devices are available to set up telephone calls or video conferences between Pcs. For conversations the one way delay is barely noticeable if it is less than 100 ms. Beyond 350 ms the delay makes the conversation unpleasant. The small delay requirement of voice implies that the voice samples must be placed in small packets. The packetization introduces a 25 ms delay that adds to the maximum delay across the network. Distortions caused by transmission errors are preferable to the excessive delays that would be required to correct the errors by retransmitting the erroneous packets.

Audio or video streams

Streaming audio and video applications enable to listen to or view a program that is being transferred. Many radio stations transmit live on the internet, and some live feeds are also available from TV stations. These streaming applications generate streams of packets that the network delivers from the source to the destination. During their travel across the network the packets suffer variable delays and same packers get dropped. The buffering absorbs the delay fluctuations. The transmission rate depends on the quality of the program. The rate of an audio transmission typically ranges from 8 Kbps to 30 Kbps. A video transmission has a rate between 40 Kbps and 80 Kbps.