An operations engineer asks for your help with a new switching deployment. The engineer confirms that STP is enabled on an edge switch, and a particular port is connected to another switch. The…

Question

Options

• ABridge Assurance is enabled on the port
• BStorm control broadcast is enabled on the port
• CREP is enabled on the port
• DBPDU Guard is enabled on the port

• A
  8% (3)
• B
  3% (1)
• C
  70% (28)
• D
  20% (8)

Explanation

REP (Resilient Ethernet Protocol) is a Cisco proprietary loop-prevention protocol designed for ring topologies that replaces STP rather than extending it. When REP is active on a port, the switch uses REP's own control mechanism instead of STP BPDUs - so the absence of BPDUs while the network functions normally is the expected behavior, not a fault.

A is wrong because Bridge Assurance requires bidirectional BPDU exchange; if BPDUs stop arriving on a BA-enabled port, the switch flags it as inconsistent and blocks it - the network would not appear healthy. B is wrong because storm control targets broadcast/multicast/unknown-unicast traffic rates and does not suppress STP BPDUs or replace loop prevention. D is wrong because BPDU Guard err-disables a port the moment it receives a BPDU - it doesn't cause BPDUs to go missing, and the port would be down, not functioning.

Memory tip: Think of REP as STP's replacement - when REP runs the show, STP BPDUs retire. If the network works fine but BPDUs vanish on a switch-to-switch link, an alternative loop-prevention protocol (REP) has taken over.

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