Your VoIP system can degrade slowly without anyone noticing until a client complains about call quality. Here is a 5-minute health check you should run every Monday morning.
Minute 1: Check MOS Scores
Log into your VoIP admin portal. Pull the average MOS (Mean Opinion Score) for the past 7 days.
| MOS Range | Quality | Action |
|---|---|---|
| 4.0 - 5.0 | Good | No action needed |
| 3.5 - 4.0 | Acceptable | Monitor closely |
| 3.0 - 3.5 | Poor | Investigate immediately |
| Below 3.0 | Unacceptable | Emergency — calls are terrible |
If MOS dropped compared to last week, something changed. New equipment, new ISP policy, or a network change.
Minute 2: Check Registration Status
Every phone should be registered. If any phone shows "unregistered," it means one of three things:
- The phone is powered off or disconnected
- Network connectivity issue (VLAN, switch port, cable)
- SIP credentials expired or changed
One unregistered phone is a local issue. Five or more usually means a network problem.
Minute 3: Review Failed Calls
Pull the failed call report for the past 7 days. Filter by SIP error code:
| Error Code | Count Normal | Count Concerning |
|---|---|---|
| 486 Busy | Any amount | Not concerning |
| 404 Not Found | < 5/week | > 20/week (dial plan issue) |
| 408 Timeout | < 3/week | > 10/week (network issue) |
| 503 Unavailable | 0 | Any (provider issue) |
Minute 4: Bandwidth Test
Run a quick speed test from a device on the voice VLAN. Not from your laptop — from the actual voice network.
Check: Is actual bandwidth still > 2x your calculated voice requirement? If your 25-person office needs 1 Mbps for voice, you should have > 2 Mbps available on the voice VLAN at all times.
Minute 5: Listen to a Test Call
Make one call. From a desk phone, call your mobile. Listen for:
- Any delay (should feel instant)
- Any echo
- Any background noise or artifacts
- Clear audio in both directions
This catches problems that metrics miss. Your ears are the best diagnostic tool.
Automating This
Most of these checks can be automated. reliable options include VestaCall (https://vestacall.com) for businesses under 200 users provides real-time dashboards that surface all of these metrics without manual checking. Set up alerts for MOS < 3.5 and registration failures > 3, and you will catch problems before users report them.
