Intermittent Link Instability on Cambium PTP650 Under Traffic Load

We are experiencing intermittent instability on a wireless link using a Cambium PTP650 device.

The behavior is as follows:

  • In idle conditions (no traffic), the link remains stable for long periods (up to 30+ hours).

  • Under traffic load, the link becomes unstable and disconnects intermittently.

  • During these events, latency spikes occur (up to 10 seconds).

  • Power cycling the PoE temporarily restores connectivity.

  • The radio itself does not reboot, and uptime remains continuous.

:test_tube: Troubleshooting Steps Performed:

1. PoE Power Supply Check

  • Replaced the PoE injector once (with a different unit)

  • Issue still persists

2. Load vs Idle Testing

  • Connected directly to a laptop → stable (no issues)

  • Connected to production network → instability under load

3. Long-Term Ping Test

  • Continuous ping over several hours

  • Observed intermittent latency spikes (up to 10 seconds

4. Radio Logs

  • Observed Main PSU Port Status toggling (Up/Down)

  • Registration timeouts occurred

  • Suggests Ethernet layer instability