SD-Switch Loop protection - active or passive?

Dear forum,
i have connected 2 x Peplink sd 24 switches using each switch‘s port 24 with 2 of my Balance router‘s LAN ports. To enhance fail-safe reliability, i also connected both switches using glass fibre channel via port 25 and turned on Loop protection (active mode) for both.
Is that correct? Or do I have to configure one of the switches to be in passive mode?
Did not understood the difference in detail acc. To the manual….
Kind regards

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Does noone has any comment on this topic?
@sitloongs : can you maybe please help me further?

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Hi,

I looked into this in more detail and wanted to share the correct setup and my learning:

Short answer:

  • I should NOT rely on Loop Protection (Active) for switch-to-switch redundancy
  • STP/RSTP must be used as the primary loop prevention mechanism
  • Loop Protection is only a fallback safety feature

My setup:

  • 2x Peplink SD Switches
  • both connected to the Balance router (2 separate LAN ports)
  • additional fiber link between the switches

This creates a Layer2 loop by design, so it must be handled properly.

Correct approach:

  • Enable RSTP on all switches (default is fine)
  • Keep all inter-switch and router uplinks as Trunk ports
  • Do NOT use Loop Protection Active on these links
  • Optionally use Loop Protection Passive as a safeguard

Reason:

  • STP/RSTP is designed exactly for this topology and will block one path cleanly
  • Loop Protection Active sends probe frames and may falsely detect loops or shut down ports
  • In redundant topologies, Active mode can interfere with STP and cause instability

When Active mode makes sense:

  • On “unsafe” access scenarios (e.g. patch panels, unknown cabling)
  • NOT on controlled uplinks between switches or to the router
  • Powerline Distributing Switch

Conclusion:

  • The topology itself is correct
  • Loop handling should be done by RSTP, not Active Loop Protection
  • Best practice:
    • Uplinks: RSTP enabled + Loop Protection Passive (optional)
    • No Active mode on these links

Hope this helps others as well.

Regards

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