QoS Configuration for VoIP Traffic

Quality of Service (QoS) prioritizes VoIP traffic over less time-sensitive data, ensuring calls remain clear even when the internet connection is busy. Without QoS, large file downloads or video streaming can cause VoIP jitter, choppy audio, and dropped calls. On the router, enable QoS and configure it to prioritize traffic by DSCP marking (VoIP traffic is typically marked DSCP EF — Expedited Forwarding, decimal 46) or by IP address/port (SIP uses port 5060, RTP audio uses ports 10000–20000 depending on the provider). Also consider bandwidth reservation: don't allow data traffic to consume more than 80% of the upload bandwidth, keeping headroom for VoIP. Each concurrent HD VoIP call uses approximately 80–90 Kbps (G.711 codec) or 30–40 Kbps (G.729). For a 10Mbps upload, you can safely support 20+ simultaneous G.729 calls without QoS, but QoS provides a safety net during peak usage.