What technique is used in VoIP communications to mask the effect of lost packets?

In VoIP communications, the technique employed to mask the effect of lost packets is known as Packet Loss Concealment. This method is crucial because in real-time communications, such as voice calls, maintaining the quality and clarity of audio is essential. When packets of audio data are lost during transmission, it can create gaps or distortions in the sound, leading to poor user experience.

Packet Loss Concealment works by utilizing algorithms that attempt to reconstruct or intelligently guess the lost portions of audio data based on the information that is still available. This process can involve techniques such as repeating the last good frame of audio, using data from surrounding frames, or utilizing estimates based on the characteristics of previous audio signals. By doing this, the overall user experience is improved, minimizing the noticeable impact of packet loss.

In contrast, other techniques listed serve different purposes. Packet Loss Notification focuses on informing the sender about lost packets rather than concealing their absence. Packet Filtering pertains to controlling data flow based on predefined rules and does not address packet loss directly. Packet Duplication involves sending multiple copies of packets to ensure delivery but does not mitigate the effects of loss in the same way that concealment does. Thus, Packet Loss Concealment is the most relevant and effective technique for