Note: This article is informational only. For official rules, always check authoritative sources and contracts.
Core metrics
- One-way latency: consistent delays matter more than occasional spikes.
- Jitter: variation in packet arrival; buffers help but add latency.
- Packet loss: even small loss rates can hurt speech quality.
Top 7 things to check
- Enable QoS marking end-to-end and confirm it’s honored.
- Avoid double NAT and ensure SIP ALG is disabled unless required.
- Confirm codec choices (G.711 vs Opus) and bandwidth headroom.
- Measure at busy hour, not just at 10am.
- Use separate VLANs where practical for voice traffic.
- Check Wi‑Fi airtime and roaming if endpoints are wireless.
- Validate provider routes and failover.
Fix path
- Start with a baseline test (RTP streams, synthetic calls).
- Apply one change at a time; keep a change log.
- Escalate with evidence: timestamps, traces, metrics.
Suggested next reading
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