Loop Guard
Loop Guard prevents loops if BPDUs stop arriving on a non-designated port.
Updated: 2026-03-06
Definition
Loop Guard protects against unidirectional link failures where BPDUs are unexpectedly lost.
It keeps the port from transitioning to forwarding and potentially creating a loop.
Key points
- Protects against unidirectional failures
- Prevents blocked ports from incorrectly forwarding
- Useful on redundant links
Common mistakes
- Assuming STP alone covers all BPDU-loss scenarios.
- Using the wrong guard feature for the problem.
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