Refer to the exhibit. The output that is shown is generated at an industrial switch. Which three statements are true? (Choose three.)

Question

Exhibit

Options

• AAll ports will be in a state of discarding, learning, or forwarding.
• BThirty VLANs have been configured on this switch.
• CThe bridge priority is lower than the default value for spanning tree.
• DAll interfaces that are shown are on shared media.
• EAll designated ports are in a forwarding state.
• FThis switch must be the root bridge for all VLANs on this switch.

• A
  71% (29)
• B
  7% (3)
• D
  20% (8)
• F
  2% (1)

Explanation

A is correct because the output shows Rapid PVST+ (or RSTP), which uses only three port states - discarding, learning, and forwarding - replacing classic STP's five states. C is correct because the bridge priority displayed is below the STP default of 32768 (e.g., 24576), indicating it was manually lowered. E is correct because it's a foundational STP rule: designated ports are always in a forwarding state by definition - no exceptions.

B is wrong because the number visible in the exhibit reflects something other than 30 configured VLANs (a common misread trap). D is wrong because the links shown are full-duplex point-to-point connections, not shared/half-duplex media - shared media is a hub-era concept. F is wrong because a lower-than-default priority makes this switch a candidate for root, but another switch with an even lower priority could still be the actual root for some or all VLANs.

Memory tip: For STP port states, remember "DLF" (Discarding → Learning → Forwarding) for RSTP, and lock in that designated ports always forward - that rule never changes regardless of topology or STP variant.

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