Remote Work & Video Call Health Auditor: ITU-T VoIP MOS Score
Diagnose why Zoom meetings freeze, screen sharing stutters, and audio turns robotic during remote work video conferences.
1. Why Video Calls Freeze Even With 300 Mbps Download Speeds
A standard 1080p Zoom or Microsoft Teams video call consumes only 3.8 Mbps of download bandwidth. The reason remote workers experience freezing video and "Your internet connection is unstable" warnings is upload latency variance (jitter) and packet loss, not download bandwidth.
Video conferencing uses the Real-Time Transport Protocol (RTP) over UDP. When someone on your home network uploads a file, your router's upstream queue overflows (Bufferbloat). Outgoing voice packets are delayed by 400ms+, causing jitter buffers to overflow and speech to garble.
2. Understanding the ITU-T G.107 VoIP MOS Score
The International Telecommunication Union defines the Mean Opinion Score (MOS) on a 1.0 to 5.0 scale:
- MOS 4.3 – 4.5 (Pristine): Broadcast studio audio, seamless 60fps screen sharing, zero jitter.
- MOS 4.0 – 4.2 (Good): Standard enterprise HD video and voice. Normal conversation flow.
- MOS 3.6 – 3.9 (Fair): Noticeable compression artifacts, slight robotic audio, periodic resolution downscaling.
- MOS Below 3.5 (Degraded): Words dropped entirely, video freezes, frequent meeting disconnects.
3. Critical Fixes for WFH Call Reliability
- Connect via Cat6 Ethernet: Removes all wireless radio contention and 2.4 GHz interference.
- Enable QoS for Real-Time RTP UDP Traffic: Prioritize UDP ports 3478-3481 and 8801-8810 on your router.
- Use Split Tunneling on Corporate VPNs: Route heavy video call streams directly to local CDN edge servers rather than backhauling through distant corporate VPN servers.