/mcpJitter and Playout Mechanism There are always some uncontrolled entities in a network that contribute towards further delays and jitter in the received voice packets. By modifying the jitter buffer on the terminating gateway the uncontrolled jitter is resolved in the voice network. Playout Mechanism The jitter buffer is a time buffer. It is provided by the terminating gateway to make the playout mechanism more effective. This is a functional diagram of the playout mechanism: When the playout control receives a voice packet, it analyzes the RTP timestamp. If the voice packet is delayed beyond the holding capacity of the jitter buffer, then the packet is immediately dropped. If the packet is within the buffering capability, it is placed in the jitter buffer. The location of this packet in the jitter buffer depends on the RTP timestamp calculated for that packet. In the event there is no available voice packet, the playout control tries to conceal it (predicts the missed out packet). If VAD is enabled, comfort noise is played. The responsibility of the playout control is to handle the events of lost packets, duplicated packets, corrupted packets, and out−of−sequence packets. These events are handled by time aligning the jittered voice packets, playing comfort noise (if VAD is configured), or even regenerating dual tone multifrequency (DTMF) tones to be played out to the host. The concealment of a voice packet is done by either prediction concealment or by silence concealment. Prediction concealment is based on the previous packet and the next packet (if available). It works best with low bitrate codecs (5 kbps to 16 kbps). Loss of voice packets for a high bitrate codec (32 kbps to 64 kbps) can potentially result in poor prediction concealment. Prediction concealment starts when there are low and infrequent delays or a lesser number of packet loss. Too much prediction concealment can lead to robotic voice quality. Silence concealment is the worst form of prediction concealment. It comes into play when there is no information available to predict. It is simply a background concealment. It starts when there are high delays and more number of packet loss. Too much silence concealment leads to choppy voice quality. The prediction concealment is good for 30 msecs after which the silence conceal comes into play.