What is difference between Timeliness and Jitter

Question

Timeliness: The system must deliver data in a timely manner. Data delivered late are useless. In the case of video and audio, timely delivery means delivering data as they are produced, in the same order that they are produced, and without significant delay. This kind of delivery is called real-time transmission. Jitter: Jitter refers to the variation in the packet arrival time. It is the uneven delay in the delivery of audio or video packets. For example, let us assume that video packets are sent every 3D ms. If some of the packets arrive with 3D-ms delay and others with 4D-ms delay, an uneven quality in the video is the result.

Answer 1

Real-time applications, such as video and VoIP, can withstand a certain amount of latency (for VoIP, this is normally considered to be 250 ms) and lost data.

Late delivery really means out-of-order delivery. Having data considered lost arrive after it is useful (e.g. packet 100 arriving after packet 110) is more disruptive than losing the data, and late-arriving data must be discarded, otherwise it creates chaos.

Unidirectional real-time data can actually stand a lot of latency: think of the seven-second delay added to real-time television and radio broadcasts. If video frames are delivered out-of-order (timeliness), they must be discarded.

Jitter is variance in latency. VoIP can withstand a fair amount of latency, as long as that latency is consistent, but, even with very good latency, a lot of jitter will kill VoIP. For instance, a VoIP latency of 50 ms is good, but having packets delivered with a lot of jitter, even keeping the maximum latency under 50 ms, will destroy VoIP.