Bridged Virtual Systems in a cluster monitor which of the following protocols, to fail over a bridged system?

Question

Options

• APBDU
• BOSPF
• CSTP
• DVTP
• EMPLS

• A
  73% (40)
• B
  2% (1)
• C
  15% (8)
• D
  4% (2)
• E
  7% (4)

Explanation

PBDU (Bridge Protocol Data Units) are the frames that carry Spanning Tree Protocol topology information across a bridged network. In a clustered environment, bridged virtual systems monitor incoming BPDU frames on their network interfaces - if BPDUs stop arriving or indicate a topology change, the cluster software detects this as a bridge failure and triggers failover to a standby node. OSPF (B) is a Layer 3 routing protocol concerned with IP path selection, not bridge-layer monitoring. STP (C) is the broader protocol that generates BPDUs - the cluster monitors the actual BPDU frames, not STP itself as a control mechanism. VTP (D) is Cisco's VLAN Trunking Protocol, used to propagate VLAN database changes across switches, and has no role in failover detection. MPLS (E) is a label-switching forwarding mechanism operating above Layer 2 bridging, unrelated to bridge failover.

Memory tip: "Bridges speak BPDUs" - whatever monitors a bridged interface is listening for Bridge Protocol Data Units. Note that the exam lists this as "PBDU," which is a transposition of the standard acronym BPDU - don't let that letter swap trip you up on test day.

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