300-320 · Question #168
Which STP enhancement can be configured on Layer 2 ports between distribution layer switches?
The correct answer is A. LoopGuard. LoopGuard protects against unidirectional link failures that could cause a non-designated (blocking) port to erroneously transition to a forwarding state when it stops receiving BPDUs. On inter-distribution Layer 2 links, a blocked port could become forwarding if its upstream…
Question
Which STP enhancement can be configured on Layer 2 ports between distribution layer switches?
Options
- ALoopGuard
- BPortFast
- CUplinkFast
- DRootGuard
How the community answered
(26 responses)- A96% (25)
- C4% (1)
Explanation
LoopGuard protects against unidirectional link failures that could cause a non-designated (blocking) port to erroneously transition to a forwarding state when it stops receiving BPDUs. On inter-distribution Layer 2 links, a blocked port could become forwarding if its upstream BPDU stream is silently lost, creating a bridging loop. LoopGuard keeps that port in a 'loop-inconsistent' blocking state instead. PortFast is intended only for end-host access ports and must never be applied to switch-to-switch links. UplinkFast accelerates failover on access-layer uplink ports, not distribution interconnects. RootGuard prevents a port from accepting a superior BPDU that would make a connected switch the new root-useful on downward-facing ports, not lateral inter-distribution links.
Topics
Community Discussion
No community discussion yet for this question.