How should you compensate for jitter on an IP network so it carries real-time VolP traffic with acceptable voice transmission quality?

VAD (Voice Activity Detection) detects silence and replaces it with comfort noise to reduce bandwidth consumption; it does not address packet timing variation caused by jitter.

A playout buffer, also called a de-jitter buffer, absorbs variable packet arrival times by holding incoming RTP audio packets for a configurable delay before rendering them to the listener. This smooths out the irregular spacing caused by network jitter, ensuring the voice stream is played back at a constant, uninterrupted rate. It is the standard mechanism for making real-time VoIP traffic tolerable over best-effort IP networks.

RSVP is a resource reservation signaling protocol used to request QoS guarantees in the network, but it does not buffer or reorder already-received packets at the endpoint to compensate for jitter.

Switching from G.729 to G.711 changes the codec bitrate and compression, affecting bandwidth and quality, but does nothing to mitigate the timing irregularities introduced by jitter.