When determining bandwidth capacity for VoIP-related call traffic, how does the voice_activity_detection (VAD) feature impact things?  Is there a specific value included in the standard calculation (formula below) to account for how much savings in b...

Why exactly does Cisco recommend an additional 5% of overhead be added to the final bandwidth per call value that results from using their VoIP bandwidth formula (below)?  It seems arbitrary.  If anyone can explain the reasoning in more detail, I'd a...